{"gene":"KLK3","run_date":"2026-04-28T18:30:27","timeline":{"discoveries":[{"year":1986,"finding":"KLK3/PSA was determined to be a serine protease with chymotrypsin-like activity. The complete amino acid sequence (240 residues) revealed the catalytic triad (His-41, Asp-96, Ser-192) characteristic of serine proteases, and the protein was shown to cleave insulin A and B chains and other substrates preferentially after hydrophobic residues (Tyr, Leu, Val, Phe), with Km ~15.3 mM and kcat ~0.075 s⁻¹ for a chymotryptic substrate. Activity was inhibited by PMSF, DFP, TLCK, aprotinin, and Zn²⁺.","method":"Amino acid sequencing, chromogenic substrate in vitro enzymatic assays, protease inhibitor profiling","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 1 — complete sequence determination plus in vitro enzymatic reconstitution with kinetic parameters; foundational paper replicated broadly","pmids":["2422647"],"is_preprint":false},{"year":1987,"finding":"The cDNA encoding KLK3/PSA was cloned from a human prostate cDNA library. The 1415-nucleotide insert codes for a signal peptide, a short propeptide, and a mature protein of 237 amino acid residues (Mr 26,089 non-glycosylated), with one N-linked glycosylation site. Sequence analysis confirmed extensive homology with kallikrein-family proteases.","method":"cDNA library screening, nucleotide sequencing","journal":"FEBS letters","confidence":"High","confidence_rationale":"Tier 1 — primary molecular cloning establishing gene structure; foundational and widely replicated","pmids":["2436946"],"is_preprint":false},{"year":1990,"finding":"Purified KLK3/PSA displayed chymotrypsin-like enzymatic activity and cleaved semenogelin and semenogelin-related proteins in a rapid and characteristic pattern (establishing semenogelin as its primary seminal substrate). Active PSA formed SDS-stable 1:1 molar complexes with alpha1-antichymotrypsin (ACT) by cleaving ACT at the same position as chymotrypsin cleaves ACT. PSA also formed complexes with alpha2-macroglobulin (which encapsulates PSA epitopes). Approximately one-third of purified PSA was enzymatically inactive due to internal cleavage C-terminal of Lys145.","method":"Aprotinin-Sepharose purification, in vitro enzymatic assay with semenogelin substrates, SDS-PAGE complex analysis, complex formation rate measurement","journal":"European journal of biochemistry","confidence":"High","confidence_rationale":"Tier 1 — direct in vitro reconstitution of enzyme-substrate and enzyme-inhibitor interactions; foundational, widely cited","pmids":["1702714"],"is_preprint":false},{"year":1992,"finding":"KLK3/PSA was identified as an IGFBP-3 protease in seminal plasma. Purified PSA cleaved 125I-labeled IGFBP-3 with a cleavage pattern identical to that of whole seminal plasma, while IGFBP-2 and IGFBP-4 were not degraded. Cleavage of IGFBP-3 by PSA markedly reduced binding affinity of the fragments to IGF-I but not IGF-II.","method":"In vitro protease assay with purified PSA and radiolabeled IGFBP-3, Western ligand blot","journal":"The Journal of clinical endocrinology and metabolism","confidence":"High","confidence_rationale":"Tier 1 — direct in vitro reconstitution with purified proteins; identifies IGFBP-3 as a specific PSA substrate","pmids":["1383255"],"is_preprint":false},{"year":1995,"finding":"Biochemical characterization confirmed that the mature PSA (237 amino acids, single-chain glycoprotein) is a serine protease with restricted chymotrypsin-like activity responsible for gel dissolution in ejaculated semen by proteolysis of the gel-forming proteins semenogelin I, semenogelin II, and fibronectin. In semen ~two-thirds of PSA is enzymatically active; the remaining 30–40% is inactive due to internal cleavage(s). A small fraction in semen is complexed to protein C inhibitor. PSA complexed to alpha1-antichymotrypsin (ACT) is the predominant molecular form in serum, though complex formation between purified proteins in vitro is slow.","method":"Biochemical characterization, in vitro protease assays, immunoassay, complex formation analysis","journal":"Scandinavian journal of clinical and laboratory investigation. Supplementum","confidence":"High","confidence_rationale":"Tier 1 — multiple orthogonal biochemical methods defining substrates and inhibitor complexes in seminal and serum contexts","pmids":["7544481"],"is_preprint":false},{"year":1995,"finding":"Recombinant PSA and hK2 (KLK2) were expressed in eukaryotic cells (Semliki Forest Virus system). Testing of 18 monoclonal anti-PSA IgGs revealed that 5 cross-reacted with recombinant hK2 with identical affinities, while 13 recognized PSA alone. Cross-reactive antibodies bind a region exposed when PSA is complexed to alpha1-antichymotrypsin, identifying the ACT-complex-exposed epitope as the shared PSA/hK2 region.","method":"Recombinant protein expression, monoclonal antibody binding assays, epitope mapping","journal":"Biochemical and biophysical research communications","confidence":"Medium","confidence_rationale":"Tier 2 — recombinant protein production with systematic antibody panel testing; single study","pmids":["7544581"],"is_preprint":false},{"year":1997,"finding":"Recombinant pro-PSA (zymogen, 244 residues with 7-amino-acid N-terminal propiece Ala-Pro-Leu-Ile-Leu-Ser-Arg) was expressed in E. coli and refolded. Pro-PSA was activated by trypsin (at 50:1 weight ratio) via cleavage at the Arg-Ile peptide bond releasing the propeptide to generate active PSA. Pro-PSA was also activated by recombinant human glandular kallikrein (hK2/KLK2) and by partially purified seminal plasma proteases. Active recombinant PSA was inhibited by alpha1-antichymotrypsin (forming ~100 kDa equimolar complex) but, unlike hK2, PSA failed to activate single-chain urokinase-type plasminogen activator.","method":"Recombinant protein expression and refolding, in vitro activation assays, chromogenic substrate enzymatic assays, SDS-PAGE","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 — reconstitution of zymogen activation with purified enzymes; multiple activating proteases tested; foundational","pmids":["9261179"],"is_preprint":false},{"year":1998,"finding":"hK2 (KLK2) rapidly converts the inactive precursor proPSA to active PSA in biochemical studies, suggesting a key in vivo regulatory role for hK2 in controlling PSA protease activity. Both PSA and hK2 are produced as secretory proteins by the same prostate epithelial cells; the potent trypsin-like activity of hK2 contrasts with the weak chymotrypsin-like activity of PSA.","method":"In vitro protease activation assays, immunoassays, comparative biochemical characterization","journal":"Critical reviews in clinical laboratory sciences","confidence":"Medium","confidence_rationale":"Tier 2 — review integrating prior in vitro biochemical findings; activation mechanism corroborated by multiple studies","pmids":["9759557"],"is_preprint":false},{"year":1999,"finding":"Trans-resveratrol (at 4-day treatment) reduced intracellular and secreted PSA protein levels in LNCaP cells by ~80% without changing androgen receptor (AR) expression levels (measured by Western blot and radioligand binding with [³H]R1881), indicating that resveratrol down-regulates PSA by an AR-independent mechanism.","method":"Cell-based treatment assay, Western blot for AR and PSA, radioligand binding assay","journal":"Anticancer research","confidence":"Low","confidence_rationale":"Tier 3 — single cell-line study, mechanistic pathway of AR-independence shown but downstream pathway not identified","pmids":["10769659"],"is_preprint":false},{"year":2000,"finding":"Two cis-elements in the 5.8 kb PSA promoter drive androgen-independent PSA expression: (1) a 440-bp androgen-responsive element enhancer core (AREc) in which AR binds AREs under androgen-deprived conditions (shown by mutation analysis and supershift experiments), and (2) a 150-bp pN/H region containing a 17-bp RI site bound by a 45-kDa cell-specific transcription factor (p45) identified by EMSA and UV cross-linking, driving AR-independent promoter activity. Juxtaposing both elements produced a chimeric supra-PSA promoter with 2–3-fold higher activity than wild-type.","method":"Promoter deletion/mutation analysis, DNase I footprinting, linker scan mutagenesis, EMSA, UV cross-linking, transient transfection","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1–2 — multiple orthogonal methods (footprinting, mutagenesis, EMSA, UV cross-linking) in two cell lines identifying distinct cis-elements","pmids":["11006269"],"is_preprint":false},{"year":2000,"finding":"KLK3/PSA and KLK2/hK2 are regulated by androgens and progestins in breast cancer cell lines. In BT-474 cells, synthetic androgen mibolerone was the most potent stimulator for both kallikreins, followed by the synthetic progestin norgestrel. Estradiol induced small but significant amounts of hK2 and PSA in BT-474 cells, supporting cross-talk between estrogen and androgen receptor signaling pathways. BT-474 cells express ~500–1000-fold more hK2 than T-47D cells, revealing cell-type-specific differential regulation of the two genes.","method":"Time-resolved fluorometric immunoassays (cell culture supernatants), steroid hormone treatment of breast cancer cell lines","journal":"Breast cancer research and treatment","confidence":"Low","confidence_rationale":"Tier 3 — secreted protein measurement without direct mechanistic pathway elucidation","pmids":["10832596"],"is_preprint":false},{"year":2002,"finding":"Unusual alternative splicing of KLK3 involving inclusion of intronic sequences adjacent to exon 1 generates a novel transcript encoding a protein called PSA-linked molecule (PSA-LM). PSA-LM shares only the signal peptide with PSA; the mature protein is entirely different and bears no similarity to the kallikrein family. PSA-LM is expressed in secretory epithelial cells of the prostate and is up-regulated by androgenic stimulation, similarly to PSA.","method":"RT-PCR, sequence analysis, immunohistochemistry, androgen stimulation experiments","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 — novel transcript characterized with androgen regulation confirmed experimentally","pmids":["11834722"],"is_preprint":false},{"year":2002,"finding":"Wild-type p53 strongly repressed PSA promoter-driven transcription and PSA protein secretion in LNCaP prostate cancer cells, while dominant-negative p53 mutants stimulated PSA expression. cDNA microarray showed a ~4-fold increase in PSA mRNA when p53 was suppressed. The inhibitory effect of wild-type p53 was abolished by trichostatin A (HDAC inhibitor), implicating histone deacetylation in the negative regulation of PSA promoter activity by p53.","method":"cDNA microarray, transient transfection with wild-type and dominant-negative p53 constructs, ELISA for secreted PSA, trichostatin A treatment","journal":"Oncogene","confidence":"Medium","confidence_rationale":"Tier 2 — multiple approaches (microarray, OE of p53 variants, pharmacologic HDAC inhibition) in single lab","pmids":["11791186"],"is_preprint":false},{"year":2003,"finding":"PSA protein (enzymatically inactive forms produced by transfection of human and rat prostate cancer cell lines) did not alter growth kinetics in vitro and did not change xenograft doubling times in vivo, demonstrating that the PSA protein itself, independent of enzymatic activity, does not significantly affect prostate cancer cell growth or angiogenesis in these models.","method":"Stable transfection of multiple prostate cancer cell lines with PSA gene, in vitro growth assays, xenograft in vivo models, fluorescent peptide substrate assay for enzymatic activity","journal":"The Prostate","confidence":"Medium","confidence_rationale":"Tier 2 — multiple cell lines and in vivo models tested; single lab","pmids":["12746846"],"is_preprint":false},{"year":2003,"finding":"N-glycan characterization of PSA from normal seminal plasma versus LNCaP tumor cells revealed distinct glycosylation patterns. Normal PSA glycans are sialylated biantennary complex structures (mono- and disialylated). LNCaP (tumor-derived) PSA glycans are neutral (non-sialylated), have higher fucose content (including alpha1-2 fucosylation forming the H2 epitope absent in normal PSA), and increased GalNAc (65% vs. 25%). These carbohydrate differences allow distinction between PSA from normal and tumor origins.","method":"N-glycan sequencing, mass spectrometry, immunoprecipitation","journal":"Glycobiology","confidence":"High","confidence_rationale":"Tier 1 — MS-based structural glycan characterization with orthogonal sequencing; directly defines PTM differences","pmids":["12626390"],"is_preprint":false},{"year":2010,"finding":"KLK2 is the protease responsible for activating PSA in biologically relevant models. PSA was activated by KLK2 when PSA- and KLK2-expressing cells were in physical contact, through co-conditioned media, and in vivo in subcutaneous co-inoculation xenografts (reduced free-to-total PSA ratio indicating more active PSA). Double-transgenic mice expressing both PSA and KLK2 in the prostate produced more active PSA than single-PSA transgenics. Active PSA expression alone over 2 years did not induce PIN or prostate cancer in transgenic mice.","method":"Cell co-culture, co-conditioned media assays, xenograft co-inoculation, double-transgenic mouse models, PSA activity assays","journal":"The Prostate","confidence":"High","confidence_rationale":"Tier 1–2 — multiple orthogonal in vitro and in vivo models confirming KLK2-mediated PSA activation; strong evidence","pmids":["20058238"],"is_preprint":false},{"year":2011,"finding":"PSA localizes to nuclei of androgen-stimulated LNCaP and C4-2B prostate cancer cells (demonstrated by immunofluorescence and subcellular fractionation). Stable shRNA or transient siRNA knockdown of PSA resulted in reduced AR protein and mRNA levels in C4-2B and VCaP cells, revealing a feedback loop where PSA positively controls AR expression. This regulation was independent of Src activation and did not appear to involve integrin-mediated Src signaling.","method":"Immunofluorescence, subcellular fractionation, shRNA/siRNA knockdown, immunoblotting, real-time PCR","journal":"The Prostate","confidence":"Medium","confidence_rationale":"Tier 2 — nuclear localization confirmed by two methods; loss-of-function with defined AR mRNA/protein phenotype in multiple cell lines; single lab","pmids":["21956655"],"is_preprint":false},{"year":2011,"finding":"The miR-99 family (miR-99a, -99b, miR-100) suppresses PSA expression in prostate cancer cells. Transfection of these miRNAs inhibited PSA expression and cell growth. Mechanistically, the miR-99 family targets SMARCA5 (a chromatin-remodeling factor), and PSA is posttranscriptionally regulated at least in part through repression of SMARCA5.","method":"miRNA transfection, microarray, polyribosomal loading analysis, quantitative RT-PCR, computational target prediction with experimental validation","journal":"Cancer research","confidence":"Medium","confidence_rationale":"Tier 2 — miRNA transfection with target validation by multiple transcriptomic methods; indirect regulation through SMARCA5","pmids":["21212412"],"is_preprint":false},{"year":2012,"finding":"Tyrosine-107 phosphorylated galectin-3 is resistant to cleavage by PSA. PSA (a chymotrypsin-like serine protease) cleaves galectin-3 after Tyr-107, disrupting galectin-3 multivalency while preserving carbohydrate binding activity. When galectin-3 Tyr-107 is phosphorylated by c-Abl kinase, PSA-mediated cleavage at that site is blocked, linking c-Abl activity with resistance to PSA proteolysis in prostate cells.","method":"In vitro cleavage assays with purified PSA, site-directed phosphorylation by c-Abl, Western blot, loss-of-PTEN cell models","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 — direct in vitro protease assay identifying substrate and showing PTM-dependent cleavage resistance; single lab","pmids":["22232548"],"is_preprint":false},{"year":2009,"finding":"PSA antiangiogenic activity is dependent on its enzymatic activity. Inactive PSA isoforms lack antiangiogenic activity in a HUVEC tube formation model. Inhibition of PSA enzymatic activity by a monoclonal antibody or small molecule inhibitors abolishes the antiangiogenic effect, while a peptide that stimulates PSA enzymatic activity enhances the antiangiogenic effect. Gene expression changes in HUVECs treated with PSA were opposite to those associated with tube formation.","method":"HUVEC tube formation assay, enzymatic activity modulation (antibody, small molecule inhibitors, stimulatory peptide), gene expression analysis","journal":"Scandinavian journal of clinical and laboratory investigation","confidence":"Medium","confidence_rationale":"Tier 2 — functional antiangiogenic assay with multiple pharmacological tools linking enzymatic activity to the phenotype; single lab","pmids":["19551556"],"is_preprint":false},{"year":2002,"finding":"NF-κB activates PSA gene expression. By expressing dominant-active MEKK1, TNF-alpha treatment, or overexpression of p50/p65, NF-κB was shown to activate a transcriptional regulatory element of the KLK3 gene. DNase I footprinting identified four NF-κB binding sites in the PSA core enhancer. Androgen-independent prostate cancer xenografts had higher constitutive NF-κB binding activity than androgen-dependent counterparts.","method":"Transient transfection with dominant-active MEKK1 or p50/p65, TNF-alpha treatment, DNase I footprinting, NF-κB binding assay in xenografts","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 1–2 — footprinting identifies binding sites; multiple genetic and pharmacological activators tested; in vivo xenograft correlation","pmids":["11909978"],"is_preprint":false},{"year":2017,"finding":"FOXM1 directly binds to Forkhead kinase (FHK) binding motifs in the PSA promoter/enhancer regions (identified by ChIP-PCR) and regulates KLK3 gene transcription. Androgen-independent C4-2 cells have more FOXM1 binding sites engaged than androgen-dependent LNCaP cells. Depletion of FOXM1 by small-molecule inhibitors significantly improved suppression of PSA transcription by the anti-AR agent Cadosax.","method":"ChIP-PCR, FOXM1 inhibitor treatment, combinatorial knockdown with anti-AR agent, gene expression analysis","journal":"Oncotarget","confidence":"Medium","confidence_rationale":"Tier 2 — ChIP identifies direct binding; pharmacological loss-of-function with defined transcriptional phenotype; single lab","pmids":["28199985"],"is_preprint":false},{"year":2018,"finding":"MRGBP promotes androgen receptor (AR)-mediated transactivation of KLK3 (PSA) and TMPRSS2. MRGBP associates with AR binding regions of these genes during androgen treatment. MRGBP interacts with MRG15 and TIP60 in prostate cancer cells. AR stimulation enhanced H3K4me1/me3 at AR binding regions; MRGBP is recruited to active gene regions via MRG15 binding to H3K4me1/3, then promotes recruitment of TIP60 and acetylation of histone variant H2A.Z at AR binding sites, which increases AR occupancy of these regions.","method":"ChIP, Co-immunoprecipitation, siRNA knockdown, gene expression analysis, histone modification mapping","journal":"Biochimica et biophysica acta. Gene regulatory mechanisms","confidence":"Medium","confidence_rationale":"Tier 2 — ChIP and Co-IP with mechanistic histone modification pathway defined; single lab","pmids":["30076933"],"is_preprint":false},{"year":2004,"finding":"HER2/ERBB3 pathway signaling stabilizes AR protein levels and optimizes AR binding to promoter/enhancer regions of androgen-regulated genes including KLK3/PSA. The dual EGFR/HER2 inhibitor PKI-166 reduced AR transcriptional activity and PSA expression. Effects were mediated by HER2/ERBB3, not EGFR, and involved kinases other than Akt.","method":"Small molecule kinase inhibition (PKI-166), genetic perturbation, AR-target gene expression analysis, AR binding to promoter regions","journal":"Cancer cell","confidence":"Medium","confidence_rationale":"Tier 2 — pharmacological and genetic perturbation with AR occupancy at KLK3 promoter; single lab","pmids":["15542435"],"is_preprint":false},{"year":2009,"finding":"RNF6, a ubiquitin E3 ligase, associates with AR and induces AR ubiquitination, promoting AR transcriptional activity and expression of a subset of AR target genes including KLK3/PSA. Knockdown of RNF6 or mutation of RNF6-induced ubiquitination acceptor sites on AR selectively altered expression of this AR target gene subset and diminished recruitment of AR and coactivators to androgen-responsive elements in the KLK3 regulatory region.","method":"Proteomic screen, Co-IP, ChIP, siRNA knockdown, ubiquitination assays, gene expression analysis in prostate cancer cells","journal":"Cancer cell","confidence":"Medium","confidence_rationale":"Tier 2 — proteomic identification plus ChIP confirmation of AR binding at KLK3 AREs; ubiquitination site mutants tested; single lab","pmids":["19345326"],"is_preprint":false},{"year":2012,"finding":"Evolutionary analysis of KLK3 and KLK2 across 22 primate species placed the KLK2-KLK3 duplication in the Catarrhini ancestor. dN/dS analysis provided evidence for adaptive evolution of KLK3 toward an expanded enzymatic spectrum with an effect on hydrolysis of the semen coagulum. Associations between mating system, number of semenogelin (SEMG) repeat units, and the number of functional KLK2 and KLK3 genes suggest that reproductive biology shaped KLK3 evolution.","method":"Comparative genomics, dN/dS calculation, phylogenetic analysis across 22 primate species","journal":"Genome biology and evolution","confidence":"Low","confidence_rationale":"Tier 4 — computational/comparative evolutionary analysis without direct functional reconstitution","pmids":["23204305"],"is_preprint":false},{"year":2000,"finding":"KLK3/PSA is a member of the expanded human kallikrein gene family (15 members on chromosome 19q13). PSA was established as a potent inhibitor of angiogenesis, and NES1/KLK10 was identified as a breast cancer tumor suppressor. Multiple newly identified kallikrein-like genes are regulated by steroid hormones.","method":"Gene family characterization by sequence analysis, hormone regulation studies, angiogenesis assay","journal":"Trends in endocrinology and metabolism: TEM","confidence":"Low","confidence_rationale":"Tier 3–4 — review integrating gene discovery data; antiangiogenic finding mentioned without detailed mechanistic assay description in this paper","pmids":["10675891"],"is_preprint":false},{"year":2017,"finding":"Genetic variations in the KLK3 coding region correlate with male infertility. Five SNPs (rs266881, rs174776, rs266875, rs35192866, rs1810020) were significantly associated with increased infertility risk in 875 infertile versus 290 fertile men. Since PSA/KLK3 is the chief executor of semenogelin fragmentation and semen liquefaction, and PSA levels correlate with sperm motility, these coding variants likely disrupt PSA enzymatic activity required for semen liquefaction.","method":"Complete coding region resequencing, genetic association study in a large ethnically matched cohort","journal":"Scientific reports","confidence":"Low","confidence_rationale":"Tier 4 — genetic association without direct functional validation of variant effects on enzymatic activity","pmids":["28894123"],"is_preprint":false}],"current_model":"KLK3/PSA is a kallikrein-family serine protease with chymotrypsin-like specificity (catalytic triad His-41, Asp-96, Ser-192) secreted as a zymogen (proPSA) that is activated primarily by KLK2 through cleavage of its 7-amino-acid propeptide; active PSA cleaves its principal seminal substrates semenogelin I/II and fibronectin to liquefy semen, also cleaves IGFBP-3 (reducing IGF-I binding) and galectin-3 (at Tyr-107, blocked by c-Abl-mediated phosphorylation), and exerts antiangiogenic activity dependent on its enzymatic activity; in circulation, active PSA is rapidly sequestered by forming SDS-stable 1:1 complexes with alpha1-antichymotrypsin or encapsulating complexes with alpha2-macroglobulin; KLK3 transcription is driven by androgen receptor binding to AREs in its promoter/enhancer, with additional AR-independent inputs from NF-κB (binding four sites in the PSA core enhancer), FOXM1 (binding FHK motifs), and a 45-kDa cell-specific factor (binding the pN/H RI element), while being negatively regulated by p53 (via histone deacetylation) and the miR-99 family (via SMARCA5 repression); MRGBP/MRG15/TIP60 promote H2A.Z acetylation at AR binding regions to enhance AR occupancy and KLK3 expression, RNF6-mediated AR ubiquitination similarly promotes AR recruitment to KLK3 regulatory elements, and HER2/ERBB3 signaling stabilizes AR protein to sustain KLK3 expression; tumor-derived PSA displays a distinct glycosylation pattern (neutral, hyperfucosylated N-glycans with H2 epitope) compared to normal PSA (sialylated biantennary structures); and PSA localizes to the nucleus of androgen-stimulated prostate cancer cells where it positively regulates AR mRNA and protein levels in a feedback loop."},"narrative":{"teleology":[{"year":1986,"claim":"Establishing that PSA is a serine protease with chymotrypsin-like specificity resolved the molecular identity of this abundant prostatic secretory protein, revealing its catalytic triad and substrate preferences.","evidence":"Complete amino acid sequencing plus in vitro kinetic assays with chromogenic substrates and protease inhibitor profiling","pmids":["2422647"],"confidence":"High","gaps":["Three-dimensional structure not yet determined","Physiological substrates not yet identified","Activation mechanism unknown"]},{"year":1987,"claim":"Cloning the KLK3 cDNA established its gene structure — signal peptide, propeptide, and mature chain — and placed it within the kallikrein protease family.","evidence":"cDNA library screening from human prostate with nucleotide sequencing","pmids":["2436946"],"confidence":"High","gaps":["Zymogen activation mechanism not characterized","Genomic organization and regulatory elements undefined"]},{"year":1990,"claim":"Identifying semenogelin as the principal PSA substrate and demonstrating SDS-stable complex formation with alpha1-antichymotrypsin defined the physiological function of PSA in semen liquefaction and established why circulating PSA is predominantly ACT-complexed.","evidence":"In vitro enzymatic assay with purified PSA and seminal substrates; SDS-PAGE analysis of PSA-ACT and PSA-alpha2-macroglobulin complexes","pmids":["1702714"],"confidence":"High","gaps":["Mechanism of zymogen activation in vivo unresolved","Semenogelin cleavage sites not fully mapped"]},{"year":1992,"claim":"Demonstration that PSA specifically cleaves IGFBP-3 (but not IGFBP-2 or -4), reducing IGF-I binding, expanded its substrate repertoire beyond semenogelin to a growth-factor regulatory axis.","evidence":"In vitro protease assay with purified PSA and radiolabeled IGFBP-3; Western ligand blot","pmids":["1383255"],"confidence":"High","gaps":["In vivo relevance of IGFBP-3 cleavage by PSA not established","Whether IGF signaling is altered in prostatic tissue by PSA-mediated IGFBP-3 cleavage unknown"]},{"year":1997,"claim":"Reconstituting zymogen activation in vitro showed that proPSA is activated by cleavage of its 7-residue propeptide by trypsin or KLK2, establishing the proteolytic cascade governing PSA maturation.","evidence":"Recombinant pro-PSA expression in E. coli, refolding, activation by purified trypsin and recombinant KLK2, SDS-PAGE and chromogenic assays","pmids":["9261179"],"confidence":"High","gaps":["Relative contribution of KLK2 versus other proteases in vivo not quantified","Spatial and temporal regulation of activation in prostatic ducts unresolved"]},{"year":2000,"claim":"Mapping of the KLK3 promoter/enhancer revealed that androgen-independent transcription is driven by both an ARE-containing enhancer core (bound by AR even without ligand) and a pN/H element bound by a 45-kDa cell-specific factor, explaining how PSA expression persists in androgen-deprived settings.","evidence":"Promoter deletion and linker scan mutagenesis, DNase I footprinting, EMSA, UV cross-linking in LNCaP and PC-3 cells","pmids":["11006269"],"confidence":"High","gaps":["Identity of p45 transcription factor unknown","Chromatin context of enhancer elements not addressed"]},{"year":2002,"claim":"Identification of four NF-κB binding sites in the PSA core enhancer and demonstration that p53 represses KLK3 through histone deacetylation revealed AR-independent transcriptional regulators that modulate PSA expression, particularly in androgen-independent prostate cancer.","evidence":"DNase I footprinting for NF-κB sites; p50/p65 overexpression and TNF-α treatment; wild-type/dominant-negative p53 transfection with trichostatin A rescue in LNCaP cells","pmids":["11909978","11791186"],"confidence":"High","gaps":["Whether NF-κB and p53 pathways interact at the PSA enhancer unknown","Direct AR-NF-κB cooperativity at the locus not tested"]},{"year":2003,"claim":"Glycan structural analysis revealed that tumor-derived PSA carries neutral, hyperfucosylated N-glycans (including H2 epitope) while normal seminal PSA is sialylated, establishing a molecular basis for distinguishing cancer-derived PSA.","evidence":"Mass spectrometry-based N-glycan sequencing of PSA from seminal plasma and LNCaP cells","pmids":["12626390"],"confidence":"High","gaps":["Whether glycan differences arise from altered glycosyltransferase expression in tumors not determined","Clinical diagnostic utility of glycoform discrimination not validated"]},{"year":2009,"claim":"Demonstrating that PSA antiangiogenic activity requires enzymatic activity (abolished by inhibitory antibodies and small molecules, enhanced by a stimulatory peptide) linked PSA's protease function to an extracellular biological process beyond semen liquefaction.","evidence":"HUVEC tube formation assay with active vs. inactive PSA isoforms, pharmacological modulation of enzymatic activity, gene expression profiling","pmids":["19551556"],"confidence":"Medium","gaps":["Substrate(s) responsible for antiangiogenic effect not identified","In vivo antiangiogenic relevance not confirmed in animal models"]},{"year":2010,"claim":"In vivo confirmation that KLK2 is the physiological activator of proPSA — using co-culture, xenograft co-inoculation, and double-transgenic mice — validated the KLK2→PSA proteolytic cascade and showed that active PSA alone does not initiate prostate neoplasia.","evidence":"Cell co-culture, conditioned media, subcutaneous xenograft co-inoculation, PSA/KLK2 double-transgenic mice monitored for 2 years","pmids":["20058238"],"confidence":"High","gaps":["Other prostatic proteases that may contribute to proPSA activation not excluded","Whether loss of PSA activation affects fertility in mice not tested"]},{"year":2011,"claim":"Discovery that PSA localizes to the nucleus in androgen-stimulated prostate cancer cells and positively regulates AR mRNA/protein levels revealed a feedback loop between PSA and its own transcriptional driver.","evidence":"Immunofluorescence and subcellular fractionation for nuclear localization; shRNA/siRNA knockdown of PSA with AR mRNA/protein quantification in C4-2B and VCaP cells","pmids":["21956655"],"confidence":"Medium","gaps":["Mechanism by which nuclear PSA regulates AR transcription unknown","Whether nuclear PSA retains enzymatic activity not determined","Not independently replicated outside the originating lab"]},{"year":2012,"claim":"Showing that c-Abl-mediated phosphorylation of galectin-3 at Tyr-107 blocks PSA cleavage at that site identified a phospho-switch that regulates PSA substrate accessibility in prostate cells.","evidence":"In vitro cleavage assays with purified PSA and galectin-3, site-directed c-Abl phosphorylation, Western blot","pmids":["22232548"],"confidence":"Medium","gaps":["In vivo relevance of galectin-3 cleavage by PSA in tumor microenvironment not established","Other phosphorylation-regulated PSA substrates not investigated"]},{"year":2018,"claim":"Elucidation of the MRGBP/MRG15/TIP60 chromatin remodeling axis showed that H2A.Z acetylation at AR binding regions of KLK3 enhances AR occupancy, providing a chromatin-level mechanism for AR-dependent KLK3 transcription.","evidence":"ChIP for histone modifications and factor occupancy, co-immunoprecipitation for MRGBP-MRG15-TIP60 complex, siRNA knockdown with gene expression readout in prostate cancer cells","pmids":["30076933"],"confidence":"Medium","gaps":["Whether H2A.Z acetylation is specific to KLK3 or shared across all AR target genes not resolved","Structural basis of MRGBP-MRG15-TIP60 complex assembly unknown"]},{"year":null,"claim":"Major unresolved questions include: the identity and mechanism of the 45-kDa cell-specific factor (p45) binding the pN/H element; the substrate(s) mediating PSA's antiangiogenic activity; the mechanism by which nuclear PSA regulates AR expression; and whether KLK3 coding variants directly impair enzymatic activity to cause male infertility.","evidence":"","pmids":[],"confidence":"Low","gaps":["No structural model of proPSA activation by KLK2 exists","Functional validation of infertility-associated KLK3 coding SNPs not performed","Nuclear import signal and nuclear interactome of PSA uncharacterized"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0140096","term_label":"catalytic activity, acting on a protein","supporting_discovery_ids":[0,2,3,4,6,18]},{"term_id":"GO:0016787","term_label":"hydrolase activity","supporting_discovery_ids":[0,2,3,4]}],"localization":[{"term_id":"GO:0005576","term_label":"extracellular region","supporting_discovery_ids":[2,4,14]},{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[16]}],"pathway":[{"term_id":"R-HSA-1474165","term_label":"Reproduction","supporting_discovery_ids":[2,4,15,27]},{"term_id":"R-HSA-392499","term_label":"Metabolism of proteins","supporting_discovery_ids":[0,3,6,18]}],"complexes":[],"partners":["KLK2","SERPINA3","IGFBP3","LGALS3","SEMG1","SEMG2","AR"],"other_free_text":[]},"mechanistic_narrative":"KLK3 encodes prostate-specific antigen (PSA), a kallikrein-family serine protease with chymotrypsin-like specificity (catalytic triad His-41, Asp-96, Ser-192) that is secreted as an inactive zymogen (proPSA) and activated principally by KLK2-mediated cleavage of its 7-amino-acid propeptide [PMID:9261179, PMID:20058238]. Active PSA liquefies the seminal coagulum by cleaving semenogelin I, semenogelin II, and fibronectin, and also proteolyzes IGFBP-3 (reducing IGF-I binding) and galectin-3 (at Tyr-107, blocked by c-Abl phosphorylation), while exerting enzymatic-activity-dependent antiangiogenic effects [PMID:1702714, PMID:1383255, PMID:22232548, PMID:19551556]. In circulation, active PSA is rapidly sequestered by alpha1-antichymotrypsin (forming SDS-stable 1:1 complexes) or alpha2-macroglobulin; tumor-derived PSA displays distinct neutral, hyperfucosylated N-glycans compared to the sialylated biantennary structures of normal seminal PSA [PMID:1702714, PMID:12626390]. KLK3 transcription is androgen receptor-driven, with AR occupancy enhanced by MRGBP/MRG15/TIP60-mediated H2A.Z acetylation and RNF6-mediated AR ubiquitination, and further modulated by NF-κB, FOXM1, p53-dependent histone deacetylation, and miR-99 family repression of SMARCA5 [PMID:11006269, PMID:11909978, PMID:30076933, PMID:19345326, PMID:11791186, PMID:21212412]."},"prefetch_data":{"uniprot":{"accession":"P07288","full_name":"Prostate-specific antigen","aliases":["Gamma-seminoprotein","Seminin","Kallikrein-3","P-30 antigen","Semenogelase"],"length_aa":261,"mass_kda":28.7,"function":"Hydrolyzes semenogelin-1 thus leading to the liquefaction of the seminal coagulum","subcellular_location":"Secreted","url":"https://www.uniprot.org/uniprotkb/P07288/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/KLK3","classification":"Not Classified","n_dependent_lines":0,"n_total_lines":1208,"dependency_fraction":0.0},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/KLK3","total_profiled":1310},"omim":[{"mim_id":"614510","title":"MICRO RNA 99B; MIR99B","url":"https://www.omim.org/entry/614510"},{"mim_id":"614509","title":"MICRO RNA 99A; MIR99A","url":"https://www.omim.org/entry/614509"},{"mim_id":"613186","title":"MICRO RNA 100; MIR100","url":"https://www.omim.org/entry/613186"},{"mim_id":"613184","title":"TRIPARTITE MOTIF-CONTAINING PROTEIN 68; TRIM68","url":"https://www.omim.org/entry/613184"},{"mim_id":"611959","title":"PROSTATE CANCER, HEREDITARY, 15; HPC15","url":"https://www.omim.org/entry/611959"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"","locations":[],"tissue_specificity":"Tissue enriched","tissue_distribution":"Detected in many","driving_tissues":[{"tissue":"prostate","ntpm":7518.2}],"url":"https://www.proteinatlas.org/search/KLK3"},"hgnc":{"alias_symbol":["PSA"],"prev_symbol":["APS"]},"alphafold":{"accession":"P03952","domains":[{"cath_id":"3.50.4.10","chopping":"26-108","consensus_level":"high","plddt":93.4858,"start":26,"end":108},{"cath_id":"3.50.4.10","chopping":"116-195","consensus_level":"high","plddt":95.449,"start":116,"end":195},{"cath_id":"3.50.4.10","chopping":"206-280","consensus_level":"medium","plddt":95.2908,"start":206,"end":280},{"cath_id":"3.50.4.10","chopping":"294-371","consensus_level":"medium","plddt":96.0522,"start":294,"end":371},{"cath_id":"2.40.10.10","chopping":"396-620","consensus_level":"medium","plddt":88.8388,"start":396,"end":620}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/P03952","model_url":"https://alphafold.ebi.ac.uk/files/AF-P03952-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-P03952-F1-predicted_aligned_error_v6.png","plddt_mean":87.88},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=KLK3","jax_strain_url":"https://www.jax.org/strain/search?query=KLK3"},"sequence":{"accession":"P03952","fasta_url":"https://rest.uniprot.org/uniprotkb/P03952.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/P03952/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/P03952"}},"corpus_meta":[{"pmid":"17029752","id":"PMC_17029752","title":"PSA-NCAM in mammalian structural plasticity and neurogenesis.","date":"2006","source":"Progress in neurobiology","url":"https://pubmed.ncbi.nlm.nih.gov/17029752","citation_count":352,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"18029831","id":"PMC_18029831","title":"Obesity-related plasma hemodilution and PSA concentration among men with prostate cancer.","date":"2007","source":"JAMA","url":"https://pubmed.ncbi.nlm.nih.gov/18029831","citation_count":280,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"9759557","id":"PMC_9759557","title":"Human Kallikrein 2 (hK2) and prostate-specific antigen (PSA): two closely related, but distinct, kallikreins in the prostate.","date":"1998","source":"Critical reviews in clinical laboratory sciences","url":"https://pubmed.ncbi.nlm.nih.gov/9759557","citation_count":267,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"33272960","id":"PMC_33272960","title":"Upadacitinib for psoriatic arthritis refractory to biologics: SELECT-PsA 2.","date":"2020","source":"Annals of the rheumatic diseases","url":"https://pubmed.ncbi.nlm.nih.gov/33272960","citation_count":180,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"9671666","id":"PMC_9671666","title":"Growth and fate of PSA-NCAM+ precursors of the postnatal brain.","date":"1998","source":"The Journal of neuroscience : the official journal of the Society for Neuroscience","url":"https://pubmed.ncbi.nlm.nih.gov/9671666","citation_count":172,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"10232600","id":"PMC_10232600","title":"Prostate-specific antigen (PSA) promoter-driven androgen-inducible expression of sodium iodide symporter in prostate cancer cell lines.","date":"1999","source":"Cancer research","url":"https://pubmed.ncbi.nlm.nih.gov/10232600","citation_count":159,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"12092452","id":"PMC_12092452","title":"APS-I/APECED: the clinical disease and therapy.","date":"2002","source":"Endocrinology and metabolism clinics of North America","url":"https://pubmed.ncbi.nlm.nih.gov/12092452","citation_count":155,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"11298800","id":"PMC_11298800","title":"PSA-NCAM modulates BDNF-dependent survival and differentiation of cortical neurons.","date":"2001","source":"The European journal of neuroscience","url":"https://pubmed.ncbi.nlm.nih.gov/11298800","citation_count":151,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"12817789","id":"PMC_12817789","title":"Update on autoimmune polyendocrine syndromes (APS).","date":"2003","source":"Acta bio-medica : Atenei Parmensis","url":"https://pubmed.ncbi.nlm.nih.gov/12817789","citation_count":148,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"18068100","id":"PMC_18068100","title":"Effects of Astragalus polysaccharides (APS) on the expression of immune response genes in head kidney, gill and spleen of the common carp, Cyprinus carpio L.","date":"2007","source":"International immunopharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/18068100","citation_count":120,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"11831554","id":"PMC_11831554","title":"Revisiting the function of PSA-NCAM in the nervous system.","date":"2001","source":"Molecular neurobiology","url":"https://pubmed.ncbi.nlm.nih.gov/11831554","citation_count":115,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"14690593","id":"PMC_14690593","title":"Structural basis for recruitment of the adaptor protein APS to the activated insulin receptor.","date":"2003","source":"Molecular cell","url":"https://pubmed.ncbi.nlm.nih.gov/14690593","citation_count":96,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"22099865","id":"PMC_22099865","title":"Expression of PSA-NCAM and synaptic proteins in the amygdala of psychiatric disorder patients.","date":"2011","source":"Journal of psychiatric research","url":"https://pubmed.ncbi.nlm.nih.gov/22099865","citation_count":91,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"11207636","id":"PMC_11207636","title":"Autoimmune polyendocrine syndrome type 1 (APS I) in Norway.","date":"2001","source":"Clinical endocrinology","url":"https://pubmed.ncbi.nlm.nih.gov/11207636","citation_count":89,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"9888391","id":"PMC_9888391","title":"Mutation analyses of North American APS-1 patients.","date":"1999","source":"Human mutation","url":"https://pubmed.ncbi.nlm.nih.gov/9888391","citation_count":86,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"10196204","id":"PMC_10196204","title":"Identification of the APS protein as a novel insulin receptor substrate.","date":"1999","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/10196204","citation_count":85,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"21465221","id":"PMC_21465221","title":"Identification of a novel prostate cancer susceptibility variant in the KLK3 gene transcript.","date":"2011","source":"Human genetics","url":"https://pubmed.ncbi.nlm.nih.gov/21465221","citation_count":77,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"14578283","id":"PMC_14578283","title":"Increased insulin sensitivity and hypoinsulinemia in APS knockout mice.","date":"2003","source":"Diabetes","url":"https://pubmed.ncbi.nlm.nih.gov/14578283","citation_count":75,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"11238898","id":"PMC_11238898","title":"SH2-B and APS are multimeric adapters that augment TrkA signaling.","date":"2001","source":"Molecular and cellular biology","url":"https://pubmed.ncbi.nlm.nih.gov/11238898","citation_count":70,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"17662026","id":"PMC_17662026","title":"Mucolipin-2 localizes to the Arf6-associated pathway and regulates recycling of GPI-APs.","date":"2007","source":"Traffic (Copenhagen, Denmark)","url":"https://pubmed.ncbi.nlm.nih.gov/17662026","citation_count":68,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"15585350","id":"PMC_15585350","title":"Pregnenolone sulfate enhances neurogenesis and PSA-NCAM in young and aged hippocampus.","date":"2005","source":"Neurobiology of aging","url":"https://pubmed.ncbi.nlm.nih.gov/15585350","citation_count":68,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"12150768","id":"PMC_12150768","title":"Distribution of PSA-NCAM expression in the amygdala of the adult rat.","date":"2002","source":"Neuroscience","url":"https://pubmed.ncbi.nlm.nih.gov/12150768","citation_count":66,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"11414788","id":"PMC_11414788","title":"Migration and multipotentiality of PSA-NCAM+ neural precursors transplanted in the developing brain.","date":"2001","source":"Molecular and cellular neurosciences","url":"https://pubmed.ncbi.nlm.nih.gov/11414788","citation_count":66,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"10769659","id":"PMC_10769659","title":"Grape-derived chemopreventive agent resveratrol decreases prostate-specific antigen (PSA) expression in LNCaP cells by an androgen receptor (AR)-independent mechanism.","date":"2000","source":"Anticancer research","url":"https://pubmed.ncbi.nlm.nih.gov/10769659","citation_count":65,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"11006269","id":"PMC_11006269","title":"Regions of prostate-specific antigen (PSA) promoter confer androgen-independent expression of PSA in prostate cancer cells.","date":"2000","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/11006269","citation_count":64,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"7544581","id":"PMC_7544581","title":"Production of recombinant PSA and HK2 and analysis of their immunologic cross-reactivity.","date":"1995","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/7544581","citation_count":59,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"11593331","id":"PMC_11593331","title":"Prostate-specific targeting using PSA promoter-based lentiviral vectors.","date":"2001","source":"Cancer gene therapy","url":"https://pubmed.ncbi.nlm.nih.gov/11593331","citation_count":59,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"36127221","id":"PMC_36127221","title":"Application of dendritic cells in tumor immunotherapy and progress in the mechanism of anti-tumor effect of Astragalus polysaccharide (APS) modulating dendritic cells: a review.","date":"2022","source":"Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie","url":"https://pubmed.ncbi.nlm.nih.gov/36127221","citation_count":57,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"22300986","id":"PMC_22300986","title":"PSA-NCAM: synaptic functions mediated by its interactions with proteoglycans and glutamate receptors.","date":"2012","source":"The international journal of biochemistry & cell biology","url":"https://pubmed.ncbi.nlm.nih.gov/22300986","citation_count":52,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"32845378","id":"PMC_32845378","title":"NETs in APS: Current Knowledge and Future Perspectives.","date":"2020","source":"Current rheumatology reports","url":"https://pubmed.ncbi.nlm.nih.gov/32845378","citation_count":51,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"15378031","id":"PMC_15378031","title":"A phenylalanine zipper mediates APS dimerization.","date":"2004","source":"Nature structural & molecular biology","url":"https://pubmed.ncbi.nlm.nih.gov/15378031","citation_count":51,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"10832596","id":"PMC_10832596","title":"Differential steroid hormone regulation of human glandular kallikrein (hK2) and prostate-specific antigen (PSA) in breast cancer cell lines.","date":"2000","source":"Breast cancer research and treatment","url":"https://pubmed.ncbi.nlm.nih.gov/10832596","citation_count":51,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"11834722","id":"PMC_11834722","title":"Unusual alternative splicing within the human kallikrein genes KLK2 and KLK3 gives rise to novel prostate-specific proteins.","date":"2002","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/11834722","citation_count":50,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"23780867","id":"PMC_23780867","title":"The dendritic spines of interneurons are dynamic structures influenced by PSA-NCAM expression.","date":"2013","source":"Cerebral cortex (New York, N.Y. : 1991)","url":"https://pubmed.ncbi.nlm.nih.gov/23780867","citation_count":50,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"25230752","id":"PMC_25230752","title":"Clinical and serologic parallels to APS-I in patients with thymomas and autoantigen transcripts in their tumors.","date":"2014","source":"Journal of immunology (Baltimore, Md. : 1950)","url":"https://pubmed.ncbi.nlm.nih.gov/25230752","citation_count":46,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"11791186","id":"PMC_11791186","title":"Expression of prostate specific antigen (PSA) is negatively regulated by p53.","date":"2002","source":"Oncogene","url":"https://pubmed.ncbi.nlm.nih.gov/11791186","citation_count":45,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"29579692","id":"PMC_29579692","title":"Prostate-specific antigen (PSA) as a possible biomarker in non-prostatic cancer: A review.","date":"2018","source":"Cancer epidemiology","url":"https://pubmed.ncbi.nlm.nih.gov/29579692","citation_count":44,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"12444928","id":"PMC_12444928","title":"The adapter protein APS associates with the multifunctional docking sites Tyr-568 and Tyr-936 in c-Kit.","date":"2003","source":"The Biochemical journal","url":"https://pubmed.ncbi.nlm.nih.gov/12444928","citation_count":44,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"16150464","id":"PMC_16150464","title":"Antioxidant properties and PC12 cell protective effects of APS-1, a polysaccharide from Aloe vera var. chinensis.","date":"2005","source":"Life sciences","url":"https://pubmed.ncbi.nlm.nih.gov/16150464","citation_count":43,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"22635208","id":"PMC_22635208","title":"Obstetric and vascular APS: same autoantibodies but different diseases?","date":"2012","source":"Lupus","url":"https://pubmed.ncbi.nlm.nih.gov/22635208","citation_count":42,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"16455776","id":"PMC_16455776","title":"Differential role of SH2-B and APS in regulating energy and glucose homeostasis.","date":"2006","source":"Endocrinology","url":"https://pubmed.ncbi.nlm.nih.gov/16455776","citation_count":42,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"11814454","id":"PMC_11814454","title":"Flavonoids can block PSA production by breast and prostate cancer cell lines.","date":"2002","source":"Clinica chimica acta; international journal of clinical chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/11814454","citation_count":38,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"7544481","id":"PMC_7544481","title":"Biochemistry of prostate specific antigen, PSA.","date":"1995","source":"Scandinavian journal of clinical and laboratory investigation. Supplementum","url":"https://pubmed.ncbi.nlm.nih.gov/7544481","citation_count":37,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"28199985","id":"PMC_28199985","title":"FOXM1 promotes the progression of prostate cancer by regulating PSA gene transcription.","date":"2017","source":"Oncotarget","url":"https://pubmed.ncbi.nlm.nih.gov/28199985","citation_count":37,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"22232548","id":"PMC_22232548","title":"Tyrosine-phosphorylated galectin-3 protein is resistant to prostate-specific antigen (PSA) cleavage.","date":"2012","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/22232548","citation_count":37,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"30732524","id":"PMC_30732524","title":"Promoter orientation of the immunomodulatory Bacteroides fragilis capsular polysaccharide A (PSA) is off in individuals with inflammatory bowel disease (IBD).","date":"2019","source":"Gut microbes","url":"https://pubmed.ncbi.nlm.nih.gov/30732524","citation_count":36,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"11488606","id":"PMC_11488606","title":"Molecular and catalytic properties of Arabidopsis thaliana adenylyl sulfate (APS)-kinase.","date":"2001","source":"Archives of biochemistry and biophysics","url":"https://pubmed.ncbi.nlm.nih.gov/11488606","citation_count":35,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"20935495","id":"PMC_20935495","title":"Reciprocal regulation among miR395, APS and SULTR2;1 in Arabidopsis thaliana.","date":"2010","source":"Plant signaling & behavior","url":"https://pubmed.ncbi.nlm.nih.gov/20935495","citation_count":34,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"11498022","id":"PMC_11498022","title":"Functional effects of APS and SH2-B on insulin receptor signalling.","date":"2001","source":"Biochemical Society transactions","url":"https://pubmed.ncbi.nlm.nih.gov/11498022","citation_count":33,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"10906742","id":"PMC_10906742","title":"Different proportions of various prostate-specific antigen (PSA) and human kallikrein 2 (hK2) forms are present in noninduced and androgen-induced LNCaP cells.","date":"2000","source":"The Prostate","url":"https://pubmed.ncbi.nlm.nih.gov/10906742","citation_count":33,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"10872802","id":"PMC_10872802","title":"Molecular cloning of the mouse APS as a member of the Lnk family adaptor proteins.","date":"2000","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/10872802","citation_count":33,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"20058238","id":"PMC_20058238","title":"Prostate-specific antigen (PSA) is activated by KLK2 in prostate cancer ex vivo models and in prostate-targeted PSA/KLK2 double transgenic mice.","date":"2010","source":"The Prostate","url":"https://pubmed.ncbi.nlm.nih.gov/20058238","citation_count":33,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"21956655","id":"PMC_21956655","title":"PSA regulates androgen receptor expression in prostate cancer cells.","date":"2011","source":"The Prostate","url":"https://pubmed.ncbi.nlm.nih.gov/21956655","citation_count":31,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"11399310","id":"PMC_11399310","title":"Genetic deletions of NCAM and PSA impair circadian function in the mouse.","date":"2001","source":"Physiology & behavior","url":"https://pubmed.ncbi.nlm.nih.gov/11399310","citation_count":31,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"17904697","id":"PMC_17904697","title":"Differential evolution of PSA-NCAM expression during aging of the rat telencephalon.","date":"2007","source":"Neurobiology of aging","url":"https://pubmed.ncbi.nlm.nih.gov/17904697","citation_count":31,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"9864329","id":"PMC_9864329","title":"pSa causes oncogenic suppression of Agrobacterium by inhibiting VirE2 protein export.","date":"1999","source":"Journal of bacteriology","url":"https://pubmed.ncbi.nlm.nih.gov/9864329","citation_count":31,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"25274378","id":"PMC_25274378","title":"The prostate cancer susceptibility variant rs2735839 near KLK3 gene is associated with aggressive prostate cancer and can stratify gleason score 7 patients.","date":"2014","source":"Clinical cancer research : an official journal of the American Association for Cancer Research","url":"https://pubmed.ncbi.nlm.nih.gov/25274378","citation_count":29,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"10536193","id":"PMC_10536193","title":"Developmental methylmercury administration alters cerebellar PSA-NCAM expression and Golgi sialyltransferase activity.","date":"1999","source":"Brain research","url":"https://pubmed.ncbi.nlm.nih.gov/10536193","citation_count":28,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"36086826","id":"PMC_36086826","title":"Astragalus polysaccharide (APS) attenuated PD-L1-mediated immunosuppression via the miR-133a-3p/MSN axis in HCC.","date":"2022","source":"Pharmaceutical biology","url":"https://pubmed.ncbi.nlm.nih.gov/36086826","citation_count":27,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"3019265","id":"PMC_3019265","title":"Properties of the purified APS-kinase from Escherichia coli and Saccharomyces cerevisiae.","date":"1986","source":"Archives of microbiology","url":"https://pubmed.ncbi.nlm.nih.gov/3019265","citation_count":27,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"36150565","id":"PMC_36150565","title":"Genome-wide identification of the TGA gene family in kiwifruit (Actinidia chinensis spp.) and revealing its roles in response to Pseudomonas syringae pv. actinidiae (Psa) infection.","date":"2022","source":"International journal of biological macromolecules","url":"https://pubmed.ncbi.nlm.nih.gov/36150565","citation_count":27,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"9494598","id":"PMC_9494598","title":"Prostate specific antigen (PSA) in breast and ovarian cancer.","date":"1997","source":"Anticancer research","url":"https://pubmed.ncbi.nlm.nih.gov/9494598","citation_count":27,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"33182499","id":"PMC_33182499","title":"Molecular Mechanisms of \"Antiphospholipid Antibodies\" and Their Paradoxical Role in the Pathogenesis of \"Seronegative APS\".","date":"2020","source":"International journal of molecular sciences","url":"https://pubmed.ncbi.nlm.nih.gov/33182499","citation_count":26,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"19823874","id":"PMC_19823874","title":"A comprehensive resequence analysis of the KLK15-KLK3-KLK2 locus on chromosome 19q13.33.","date":"2009","source":"Human genetics","url":"https://pubmed.ncbi.nlm.nih.gov/19823874","citation_count":25,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"33341301","id":"PMC_33341301","title":"Arterial thrombosis in antiphospholipid syndrome (APS): Clinical approach and treatment. A systematic review.","date":"2020","source":"Blood reviews","url":"https://pubmed.ncbi.nlm.nih.gov/33341301","citation_count":25,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"2981860","id":"PMC_2981860","title":"APS kinase from Penicillium chrysogenum. Dissociation and reassociation of subunits as the basis of the reversible heat inactivation.","date":"1985","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/2981860","citation_count":25,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"12746846","id":"PMC_12746846","title":"Prostate-specific antigen (PSA) protein does not affect growth of prostate cancer cells in vitro or prostate cancer xenografts in vivo.","date":"2003","source":"The Prostate","url":"https://pubmed.ncbi.nlm.nih.gov/12746846","citation_count":25,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"18627344","id":"PMC_18627344","title":"Development of peptides specifically modulating the activity of KLK2 and KLK3.","date":"2008","source":"Biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/18627344","citation_count":24,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"28894123","id":"PMC_28894123","title":"Mutations in the prostate specific antigen (PSA/KLK3) correlate with male infertility.","date":"2017","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/28894123","citation_count":24,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"25603036","id":"PMC_25603036","title":"Targeting extra-articular manifestations in PsA: a closer look at enthesitis and dactylitis.","date":"2015","source":"Current opinion in rheumatology","url":"https://pubmed.ncbi.nlm.nih.gov/25603036","citation_count":24,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"10234897","id":"PMC_10234897","title":"Prostate-specific antigen (PSA) in women.","date":"1999","source":"The Journal of the Louisiana State Medical Society : official organ of the Louisiana State Medical Society","url":"https://pubmed.ncbi.nlm.nih.gov/10234897","citation_count":23,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"25250323","id":"PMC_25250323","title":"Multiparametric MRI in the PSA screening era.","date":"2014","source":"BioMed research international","url":"https://pubmed.ncbi.nlm.nih.gov/25250323","citation_count":23,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"30626879","id":"PMC_30626879","title":"Role of APS reductase in biogeochemical sulfur isotope fractionation.","date":"2019","source":"Nature communications","url":"https://pubmed.ncbi.nlm.nih.gov/30626879","citation_count":23,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"9882457","id":"PMC_9882457","title":"Adenosine 5'-phosphosulfate (APS) kinase: diagnosing the mechanism of substrate inhibition.","date":"1999","source":"Archives of biochemistry and biophysics","url":"https://pubmed.ncbi.nlm.nih.gov/9882457","citation_count":23,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"7846147","id":"PMC_7846147","title":"DNA sequence of direct repeats of the sulI gene of plasmid pSa.","date":"1994","source":"Plasmid","url":"https://pubmed.ncbi.nlm.nih.gov/7846147","citation_count":23,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"30076933","id":"PMC_30076933","title":"MRGBP promotes AR-mediated transactivation of KLK3 and TMPRSS2 via acetylation of histone H2A.Z in prostate cancer cells.","date":"2018","source":"Biochimica et biophysica acta. Gene regulatory mechanisms","url":"https://pubmed.ncbi.nlm.nih.gov/30076933","citation_count":23,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"34549452","id":"PMC_34549452","title":"Characteristics of α2,3-sialyl N-glycosylated PSA as a biomarker for clinically significant prostate cancer in men with elevated PSA level.","date":"2021","source":"The Prostate","url":"https://pubmed.ncbi.nlm.nih.gov/34549452","citation_count":23,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"19551556","id":"PMC_19551556","title":"Antiangiogenic properties of prostate-specific antigen (PSA).","date":"2009","source":"Scandinavian journal of clinical and laboratory investigation","url":"https://pubmed.ncbi.nlm.nih.gov/19551556","citation_count":22,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"15946664","id":"PMC_15946664","title":"The interaction between the adaptor protein APS and Enigma is involved in actin organisation.","date":"2005","source":"Experimental cell research","url":"https://pubmed.ncbi.nlm.nih.gov/15946664","citation_count":22,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"22635207","id":"PMC_22635207","title":"Pathophysiology of thrombotic APS: where do we stand?","date":"2012","source":"Lupus","url":"https://pubmed.ncbi.nlm.nih.gov/22635207","citation_count":22,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"18202763","id":"PMC_18202763","title":"Down-regulation of androgen-receptor and PSA by phytochemicals.","date":"2008","source":"International journal of oncology","url":"https://pubmed.ncbi.nlm.nih.gov/18202763","citation_count":21,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"31400147","id":"PMC_31400147","title":"Clustering in the Golgi apparatus governs sorting and function of GPI-APs in polarized epithelial cells.","date":"2019","source":"FEBS letters","url":"https://pubmed.ncbi.nlm.nih.gov/31400147","citation_count":21,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"9492309","id":"PMC_9492309","title":"Cloning, sequencing, and expression of the PSA genes from Leishmania infantum.","date":"1998","source":"European journal of biochemistry","url":"https://pubmed.ncbi.nlm.nih.gov/9492309","citation_count":21,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"29941675","id":"PMC_29941675","title":"The inverse relationship between prostate specific antigen (PSA) and obesity.","date":"2018","source":"Endocrine-related cancer","url":"https://pubmed.ncbi.nlm.nih.gov/29941675","citation_count":21,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"35166175","id":"PMC_35166175","title":"Astragalus polysaccharide (APS) exerts protective effect against acute ischemic stroke (AIS) through enhancing M2 micoglia polarization by regulating adenosine triphosphate (ATP)/ purinergic receptor (P2X7R) axis.","date":"2022","source":"Bioengineered","url":"https://pubmed.ncbi.nlm.nih.gov/35166175","citation_count":21,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"19914818","id":"PMC_19914818","title":"Ultrasensitive electrochemical immunoassay based on cadmium ion-functionalized PSA@PAA nanospheres.","date":"2009","source":"Biosensors & bioelectronics","url":"https://pubmed.ncbi.nlm.nih.gov/19914818","citation_count":20,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"12783326","id":"PMC_12783326","title":"The small subunit ADP-glucose pyrophosphorylase ( ApS) promoter mediates okadaic acid-sensitive uidA expression in starch-synthesizing tissues and cells in Arabidopsis.","date":"2003","source":"Planta","url":"https://pubmed.ncbi.nlm.nih.gov/12783326","citation_count":20,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"10102796","id":"PMC_10102796","title":"Lymphocyte activation and cytokine production by Pisum sativum agglutinin (PSA) in vivo and in vitro.","date":"1999","source":"Immunopharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/10102796","citation_count":19,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"32898689","id":"PMC_32898689","title":"The neuroplasticity marker PSA-NCAM: Insights into new therapeutic avenues for promoting neuroregeneration.","date":"2020","source":"Pharmacological research","url":"https://pubmed.ncbi.nlm.nih.gov/32898689","citation_count":18,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"33249717","id":"PMC_33249717","title":"Insight into the hypercoagulable state of high-risk thrombotic APS patients: Contribution of aβ2GPI and aPS/PT antibodies.","date":"2020","source":"Journal of thrombosis and haemostasis : JTH","url":"https://pubmed.ncbi.nlm.nih.gov/33249717","citation_count":18,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"17105811","id":"PMC_17105811","title":"Acquisition of antigen presentasome (APS), an MHC/costimulatory complex, is a checkpoint of memory T-cell homeostasis.","date":"2006","source":"Blood","url":"https://pubmed.ncbi.nlm.nih.gov/17105811","citation_count":17,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"21854254","id":"PMC_21854254","title":"Association between saliva PSA and serum PSA in conditions with prostate adenocarcinoma.","date":"2011","source":"Biomarkers : biochemical indicators of exposure, response, and susceptibility to chemicals","url":"https://pubmed.ncbi.nlm.nih.gov/21854254","citation_count":17,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"26168034","id":"PMC_26168034","title":"The Obesity-Linked Gene Nudt3 Drosophila Homolog Aps Is Associated With Insulin Signaling.","date":"2015","source":"Molecular endocrinology (Baltimore, Md.)","url":"https://pubmed.ncbi.nlm.nih.gov/26168034","citation_count":17,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"36327902","id":"PMC_36327902","title":"Accurate diagnosis of prostate cancer with CRISPR-based nucleic acid test strip by simultaneously identifying PCA3 and KLK3 genes.","date":"2022","source":"Biosensors & bioelectronics","url":"https://pubmed.ncbi.nlm.nih.gov/36327902","citation_count":15,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"34048566","id":"PMC_34048566","title":"PSA controls hepatic lipid metabolism by regulating the NRF2 signaling pathway.","date":"2021","source":"Journal of molecular cell biology","url":"https://pubmed.ncbi.nlm.nih.gov/34048566","citation_count":15,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"29630104","id":"PMC_29630104","title":"Early diagnostic role of PSA combined miR-155 detection in prostate cancer.","date":"2018","source":"European review for medical and pharmacological sciences","url":"https://pubmed.ncbi.nlm.nih.gov/29630104","citation_count":15,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"31425516","id":"PMC_31425516","title":"Characterization of Entamoeba histolytica adenosine 5'-phosphosulfate (APS) kinase; validation as a target and provision of leads for the development of new drugs against amoebiasis.","date":"2019","source":"PLoS neglected tropical diseases","url":"https://pubmed.ncbi.nlm.nih.gov/31425516","citation_count":14,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"37993717","id":"PMC_37993717","title":"Autoimmune amelogenesis imperfecta in patients with APS-1 and coeliac disease.","date":"2023","source":"Nature","url":"https://pubmed.ncbi.nlm.nih.gov/37993717","citation_count":13,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"23204305","id":"PMC_23204305","title":"Birth-and-death of KLK3 and KLK2 in primates: evolution driven by reproductive biology.","date":"2012","source":"Genome biology and evolution","url":"https://pubmed.ncbi.nlm.nih.gov/23204305","citation_count":13,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"34455138","id":"PMC_34455138","title":"Candidiasis in patients with APS-1: low IL-17, high IFN-γ, or both?","date":"2021","source":"Current opinion in immunology","url":"https://pubmed.ncbi.nlm.nih.gov/34455138","citation_count":13,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"12477932","id":"PMC_12477932","title":"Generation and initial analysis of more than 15,000 full-length human and mouse cDNA sequences.","date":"2002","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/12477932","citation_count":1479,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"26186194","id":"PMC_26186194","title":"The BioPlex Network: A Systematic Exploration of the Human Interactome.","date":"2015","source":"Cell","url":"https://pubmed.ncbi.nlm.nih.gov/26186194","citation_count":1118,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"28514442","id":"PMC_28514442","title":"Architecture of the human interactome defines protein communities and disease networks.","date":"2017","source":"Nature","url":"https://pubmed.ncbi.nlm.nih.gov/28514442","citation_count":1085,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"33961781","id":"PMC_33961781","title":"Dual proteome-scale networks reveal cell-specific remodeling of the human interactome.","date":"2021","source":"Cell","url":"https://pubmed.ncbi.nlm.nih.gov/33961781","citation_count":705,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"18264097","id":"PMC_18264097","title":"Multiple newly identified loci associated with prostate cancer susceptibility.","date":"2008","source":"Nature genetics","url":"https://pubmed.ncbi.nlm.nih.gov/18264097","citation_count":673,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"14718574","id":"PMC_14718574","title":"The human plasma proteome: a nonredundant list developed by combination of four separate sources.","date":"2004","source":"Molecular & cellular proteomics : MCP","url":"https://pubmed.ncbi.nlm.nih.gov/14718574","citation_count":658,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"21873635","id":"PMC_21873635","title":"Phylogenetic-based propagation of functional annotations within the Gene Ontology consortium.","date":"2011","source":"Briefings in bioinformatics","url":"https://pubmed.ncbi.nlm.nih.gov/21873635","citation_count":656,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"1702714","id":"PMC_1702714","title":"Enzymatic activity of prostate-specific antigen and its reactions with extracellular serine proteinase inhibitors.","date":"1990","source":"European journal of biochemistry","url":"https://pubmed.ncbi.nlm.nih.gov/1702714","citation_count":572,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"2422647","id":"PMC_2422647","title":"Human prostate-specific antigen: structural and functional similarity with serine proteases.","date":"1986","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/2422647","citation_count":545,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"1383255","id":"PMC_1383255","title":"Prostate-specific antigen (PSA) is an insulin-like growth factor binding protein-3 protease found in seminal plasma.","date":"1992","source":"The Journal of clinical endocrinology and metabolism","url":"https://pubmed.ncbi.nlm.nih.gov/1383255","citation_count":463,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"15489334","id":"PMC_15489334","title":"The status, quality, and expansion of the NIH full-length cDNA project: the Mammalian Gene Collection (MGC).","date":"2004","source":"Genome research","url":"https://pubmed.ncbi.nlm.nih.gov/15489334","citation_count":438,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"2436946","id":"PMC_2436946","title":"Molecular cloning of human prostate specific antigen cDNA.","date":"1987","source":"FEBS letters","url":"https://pubmed.ncbi.nlm.nih.gov/2436946","citation_count":355,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"22705054","id":"PMC_22705054","title":"Genomic deletion of PTEN is associated with tumor progression and early PSA recurrence in ERG fusion-positive and fusion-negative prostate cancer.","date":"2012","source":"The American journal of pathology","url":"https://pubmed.ncbi.nlm.nih.gov/22705054","citation_count":275,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"15542435","id":"PMC_15542435","title":"HER2/neu kinase-dependent modulation of androgen receptor function through effects on DNA binding and stability.","date":"2004","source":"Cancer cell","url":"https://pubmed.ncbi.nlm.nih.gov/15542435","citation_count":273,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"15829968","id":"PMC_15829968","title":"Transcriptional regulation of a metastasis suppressor gene by Tip60 and beta-catenin complexes.","date":"2005","source":"Nature","url":"https://pubmed.ncbi.nlm.nih.gov/15829968","citation_count":264,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"15174051","id":"PMC_15174051","title":"An investigation into the human serum \"interactome\".","date":"2004","source":"Electrophoresis","url":"https://pubmed.ncbi.nlm.nih.gov/15174051","citation_count":247,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"10675891","id":"PMC_10675891","title":"The new human kallikrein gene family: implications in carcinogenesis.","date":"2000","source":"Trends in endocrinology and metabolism: TEM","url":"https://pubmed.ncbi.nlm.nih.gov/10675891","citation_count":243,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"12626390","id":"PMC_12626390","title":"Altered glycosylation pattern allows the distinction between prostate-specific antigen (PSA) from normal and tumor origins.","date":"2003","source":"Glycobiology","url":"https://pubmed.ncbi.nlm.nih.gov/12626390","citation_count":228,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"21212412","id":"PMC_21212412","title":"miR-99 family of MicroRNAs suppresses the expression of prostate-specific antigen and prostate cancer cell proliferation.","date":"2011","source":"Cancer research","url":"https://pubmed.ncbi.nlm.nih.gov/21212412","citation_count":202,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"28694142","id":"PMC_28694142","title":"Increased PSA expression on prostate cancer exosomes in in vitro condition and in cancer patients.","date":"2017","source":"Cancer letters","url":"https://pubmed.ncbi.nlm.nih.gov/28694142","citation_count":199,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"19345326","id":"PMC_19345326","title":"Regulation of androgen receptor transcriptional activity and specificity by RNF6-induced ubiquitination.","date":"2009","source":"Cancer cell","url":"https://pubmed.ncbi.nlm.nih.gov/19345326","citation_count":191,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"19690023","id":"PMC_19690023","title":"Influence of trigger PSA and PSA kinetics on 11C-Choline PET/CT detection rate in patients with biochemical relapse after radical prostatectomy.","date":"2009","source":"Journal of nuclear medicine : official publication, Society of Nuclear Medicine","url":"https://pubmed.ncbi.nlm.nih.gov/19690023","citation_count":188,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"19380444","id":"PMC_19380444","title":"Prostate-specific antigen progression predicts overall survival in patients with metastatic prostate cancer: data from Southwest Oncology Group Trials 9346 (Intergroup Study 0162) and 9916.","date":"2009","source":"Journal of clinical oncology : official journal of the American Society of Clinical Oncology","url":"https://pubmed.ncbi.nlm.nih.gov/19380444","citation_count":185,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"22325447","id":"PMC_22325447","title":"Three-Tesla magnetic resonance-guided prostate biopsy in men with increased prostate-specific antigen and repeated, negative, random, systematic, transrectal ultrasound biopsies: detection of clinically significant prostate cancers.","date":"2012","source":"European urology","url":"https://pubmed.ncbi.nlm.nih.gov/22325447","citation_count":185,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"15531881","id":"PMC_15531881","title":"Rate of molecular evolution of the seminal protein gene SEMG2 correlates with levels of female promiscuity.","date":"2004","source":"Nature genetics","url":"https://pubmed.ncbi.nlm.nih.gov/15531881","citation_count":184,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"19542190","id":"PMC_19542190","title":"Tea polyphenols decrease serum levels of prostate-specific antigen, hepatocyte growth factor, and vascular endothelial growth factor in prostate cancer patients and inhibit production of hepatocyte growth factor and vascular endothelial growth factor in vitro.","date":"2009","source":"Cancer prevention research (Philadelphia, Pa.)","url":"https://pubmed.ncbi.nlm.nih.gov/19542190","citation_count":181,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"9261179","id":"PMC_9261179","title":"Characterization of the precursor of prostate-specific antigen. Activation by trypsin and by human glandular kallikrein.","date":"1997","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/9261179","citation_count":180,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"11909978","id":"PMC_11909978","title":"NF-kappa B activates prostate-specific antigen expression and is upregulated in androgen-independent prostate cancer.","date":"2002","source":"Molecular and cellular biology","url":"https://pubmed.ncbi.nlm.nih.gov/11909978","citation_count":170,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"27911486","id":"PMC_27911486","title":"Extended mortality results for prostate cancer screening in the PLCO trial with median follow-up of 15 years.","date":"2016","source":"Cancer","url":"https://pubmed.ncbi.nlm.nih.gov/27911486","citation_count":170,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"19913121","id":"PMC_19913121","title":"Gene-centric association signals for lipids and apolipoproteins identified via the HumanCVD BeadChip.","date":"2009","source":"American journal of human genetics","url":"https://pubmed.ncbi.nlm.nih.gov/19913121","citation_count":164,"is_preprint":false,"source_track":"gene2pubmed"}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":47030,"output_tokens":4033,"usd":0.100792},"stage2":{"model":"claude-opus-4-6","input_tokens":7466,"output_tokens":2566,"usd":0.15222},"total_usd":0.630375,"stage1_batch_id":"msgbatch_01Mgbec4vM6c9vXht7JVJzss","stage2_batch_id":"msgbatch_01JkuuH5RB2BdJNsgnhjbC6s","note":"batch pricing = 50% of standard","round2_stage1":{"model":"claude-sonnet-4-6","input_tokens":62361,"output_tokens":8876,"usd":0.160111},"round2_rules_fired":"R3","round2_stage2":{"model":"claude-opus-4-6","input_tokens":11837,"output_tokens":3426,"usd":0.217252}},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 1995,\n      \"finding\": \"KLK3 (PSA) is a serine protease with restricted chymotrypsin-like activity that is primarily responsible for gel dissolution in seminal fluid by proteolysis of semenogelin I and II and fibronectin. In semen, approximately two-thirds of PSA is enzymatically active; the remaining fraction is inactive due to internal cleavage(s). PSA forms stable complexes with alpha-1-antichymotrypsin (ACT) and alpha-2-macroglobulin in vitro.\",\n      \"method\": \"Biochemical characterization of purified PSA, in vitro protease assays, complex formation studies\",\n      \"journal\": \"Scandinavian journal of clinical and laboratory investigation. Supplementum\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — in vitro enzymatic assay with substrate identification, replicated across the field\",\n      \"pmids\": [\"7544481\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1998,\n      \"finding\": \"The inactive precursor form of PSA (proPSA) is converted to active PSA by human kallikrein 2 (hK2/KLK2) in vitro, suggesting an important in vivo regulatory function by hK2 on PSA activity. hK2 has trypsin-like activity while PSA has weak chymotrypsin-like activity.\",\n      \"method\": \"In vitro protease activity assays, recombinant protein production\",\n      \"journal\": \"Critical reviews in clinical laboratory sciences\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — in vitro reconstitution of zymogen activation, supported by multiple subsequent studies\",\n      \"pmids\": [\"9759557\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1995,\n      \"finding\": \"Recombinant PSA and hK2 were produced and immunological cross-reactivity analyzed; 5 of 18 monoclonal anti-PSA antibodies cross-reacted with hK2 with identical affinities, and the cross-reactive epitope is exposed when PSA is complexed to alpha-1-antichymotrypsin.\",\n      \"method\": \"Recombinant protein expression (Semliki Forest Virus system), monoclonal antibody binding assays\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — recombinant protein production with antibody characterization, single study\",\n      \"pmids\": [\"7544581\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"PSA expression is negatively regulated by p53; suppression of the p53 pathway in LNCaP cells resulted in 4-8-fold increase in PSA secretion. Wild-type p53 strongly repressed PSA promoter-driven transcription, while the inhibitory effect was abolished by trichostatin A, implicating histone deacetylation in the mechanism of p53-mediated repression of the PSA promoter.\",\n      \"method\": \"cDNA microarray, transient transfection with dominant-negative p53 mutants, PSA promoter-reporter assays, trichostatin A treatment\",\n      \"journal\": \"Oncogene\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — promoter-reporter and pharmacological inhibitor assays, single lab\",\n      \"pmids\": [\"11791186\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"Two cis-elements in the 5.8-kb PSA promoter mediate androgen-independent activity: the androgen-responsive element enhancer core (AREc) is bound by androgen receptor (AR) even under androgen-deprived conditions, and a 150-bp pN/H region containing a 17-bp RI site is bound by a 45-kDa prostate cell-specific transcription factor (p45) and drives AR-independent PSA promoter activity.\",\n      \"method\": \"Deletion and mutation analysis of PSA promoter, DNase I footprinting, linker scan mutagenesis, EMSA, UV cross-linking, transient transfection in LNCaP and C4-2 cells\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — multiple orthogonal methods including footprinting, EMSA, mutagenesis, and functional reporter assays\",\n      \"pmids\": [\"11006269\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"Androgens not only upregulate expression of PSA and hK2 in LNCaP cells but also significantly affect processing: androgen induction increases the ratio of mature to pro-PSA, and nearly 100% mature hK2 is produced in androgen-induced cells versus mostly pro-hK2 in noninduced cells. PSA and hK2 are secreted as precursor (pro) forms and converted to mature forms extracellularly.\",\n      \"method\": \"LNCaP cell culture with androgen induction (mibolerone), immunoassays of spent media for proPSA, mature PSA, prohK2, and mature hK2\",\n      \"journal\": \"The Prostate\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — cell-based assays with biochemical fractionation, single lab\",\n      \"pmids\": [\"10906742\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"Unusual alternative splicing of KLK3 resulting from inclusion of intronic sequences adjacent to the first exon gives rise to a novel transcript encoding PSA-linked molecule (PSA-LM), which shares only the signal peptide with PSA; the mature protein is entirely different. PSA-LM is expressed in secretory epithelial cells of the prostate and is upregulated by androgenic stimulation.\",\n      \"method\": \"Identification and cloning of novel splice variants, expression analysis in prostate tissue\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — molecular cloning and expression analysis, single study\",\n      \"pmids\": [\"11834722\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"KLK2 is the protease responsible for activating PSA (KLK3) in biologically relevant models: PSA is activated by KLK2 when cells are physically in contact and via co-conditioned media in vitro; in vivo, co-inoculation of PSA- and KLK2-expressing cells decreases the free-to-total PSA ratio in blood, indicating increased active PSA. Double-transgenic mice expressing both genes in the prostate produce more active PSA than single-transgenic animals.\",\n      \"method\": \"Cell-based co-incubation assays, xenograft co-inoculation in vivo, prostate-targeted PSA/KLK2 double-transgenic mice\",\n      \"journal\": \"The Prostate\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — multi-model validation including in vitro, xenograft, and transgenic animal studies\",\n      \"pmids\": [\"20058238\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"PSA localizes to nuclei of androgen-stimulated prostate cancer cells and controls AR mRNA and protein levels: stable shRNA or transient siRNA knockdown of PSA reduces AR protein and mRNA levels in C4-2B and VCaP cells. This regulatory loop does not involve Src or AKT.\",\n      \"method\": \"Immunofluorescence, subcellular fractionation, shRNA and siRNA knockdown, Western blot, real-time PCR\",\n      \"journal\": \"The Prostate\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — clean KD with multiple readouts, single lab\",\n      \"pmids\": [\"21956655\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"PSA (KLK3) cleaves galectin-3 at Tyr-107 as a chymotrypsin-like serine protease, resulting in loss of galectin-3 multivalency while preserving its carbohydrate binding activity. Tyrosine-107 phosphorylation of galectin-3 by c-Abl renders it resistant to PSA cleavage.\",\n      \"method\": \"In vitro cleavage assay with PSA and galectin-3, c-Abl phosphorylation assay, functional analysis of galectin-3 multivalency\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — in vitro substrate cleavage assay with post-translational modification cross-talk, single lab\",\n      \"pmids\": [\"22232548\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"The antiangiogenic activity of PSA (KLK3) is dependent on its enzymatic activity: inactive PSA isoforms lack antiangiogenic activity in HUVEC tube formation assays, inhibition of PSA enzymatic activity by monoclonal antibody or small molecule inhibitors abolishes the antiangiogenic effect, and a peptide that stimulates PSA activity enhances its antiangiogenic effect.\",\n      \"method\": \"HUVEC tube formation assay, monoclonal antibody inhibition, small molecule inhibitors of PSA, peptide stimulation of PSA activity\",\n      \"journal\": \"Scandinavian journal of clinical and laboratory investigation\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — functional assay with pharmacological inhibition and gain-of-function, single lab\",\n      \"pmids\": [\"19551556\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1999,\n      \"finding\": \"PSA promoter drives androgen-dependent, prostate-specific expression: when hNIS cDNA is coupled to the PSA promoter and transfected into androgen-sensitive LNCaP cells, perchlorate-sensitive iodide uptake is observed only upon androgen treatment, and not in androgen-deprived cells or in PSA-negative cell lines (PC-3 and DU-145).\",\n      \"method\": \"Transient and stable transfection of NIS/PSA promoter constructs, iodide uptake assays, Western blotting\",\n      \"journal\": \"Cancer research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — functional promoter characterization with multiple cell lines, single study\",\n      \"pmids\": [\"10232600\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"FOXM1 directly binds to FHK binding motifs in the PSA (KLK3) promoter/enhancer regions and promotes PSA gene transcription in prostate cancer cells, particularly in androgen-independent cells. Androgen-independent C4-2 cells have more FOXM1 binding sites than androgen-dependent LNCaP cells.\",\n      \"method\": \"ChIP-PCR screening of FOXM1 binding sites, FOXM1 depletion by small molecule inhibitors, PSA reporter assays\",\n      \"journal\": \"Oncotarget\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — ChIP with functional knockdown, single lab\",\n      \"pmids\": [\"28199985\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"MRGBP promotes androgen receptor (AR)-mediated transactivation of KLK3 by interacting with MRG15 and TIP60; MRGBP is recruited to active gene regions through its binding with H3K4me1/3 via MRG15, then promotes TIP60 recruitment and acetylation of histone variant H2A.Z at AR binding regions, increasing AR occupancy.\",\n      \"method\": \"ChIP assays, co-immunoprecipitation, histone modification analysis, shRNA knockdown\",\n      \"journal\": \"Biochimica et biophysica acta. Gene regulatory mechanisms\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — ChIP, Co-IP, and functional knockdown with histone modification readout, single lab\",\n      \"pmids\": [\"30076933\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"A non-synonymous coding SNP in KLK3 (rs17632542, Ile179Thr) is associated with PSA levels and prostate cancer risk; molecular dynamic simulation suggests this variant has potential to alter protein structure or affect RNA splicing.\",\n      \"method\": \"GWAS genotyping, direct genotyping in 10,405 cases and 10,681 controls, molecular dynamic simulation\",\n      \"journal\": \"Human genetics\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 4 — genetic association with computational structural prediction, no direct biochemical validation\",\n      \"pmids\": [\"21465221\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"KLK3 (PSA) genetic variants in the coding region correlate with male infertility; PSA is identified as the chief executor of semenogelin fragmentation and semen coagulum dissolution, and PSA level/activity affects sperm motility and fertility.\",\n      \"method\": \"Sequencing of complete coding region of KLK3 in 875 infertile and 290 fertile men, statistical association analysis\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 — genetic association study, functional role of PSA in semen liquefaction established by prior biochemistry\",\n      \"pmids\": [\"28894123\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"KLK3 and KLK2 arose from a duplication event in the Catarrhini ancestor; KLK3 shows evidence of adaptive evolution toward an expanded enzymatic spectrum, with effect on hydrolysis of semen coagulum; associations found between mating system, SEMG repeat units, and functional KLK2/KLK3 copy number.\",\n      \"method\": \"Comparative genomic analysis of 22 primate species, dN/dS ratio calculation, evolutionary reconstruction\",\n      \"journal\": \"Genome biology and evolution\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 4 — computational/evolutionary analysis, no direct biochemical validation\",\n      \"pmids\": [\"23204305\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"KLK3 (PSA) is a serine protease with chymotrypsin-like specificity, secreted as an inactive zymogen (proPSA) that is activated extracellularly by KLK2 (hK2); active PSA cleaves semenogelin I/II and fibronectin to liquefy seminal coagulum, cleaves galectin-3 after Tyr-107 (a cleavage blocked by c-Abl phosphorylation), and exerts antiangiogenic activity dependent on its enzymatic activity; PSA expression is transcriptionally driven by androgen receptor acting on androgen-responsive elements in the KLK3 promoter, co-activated by FOXM1 and the MRGBP/MRG15/TIP60 epigenetic complex, and negatively regulated by p53 via histone deacetylation, while PSA itself localizes to the nucleus in androgen-stimulated cells and positively regulates AR mRNA and protein levels.\"\n}\n```\n\n--- ROUND 2 (R2/R3, augmented corpus) ---\n\nI'll systematically classify papers before extracting discoveries.\n\n**Classification of relevant papers for KLK3 (PSA, prostate-specific antigen):**\n\nKEEP papers about canonical KLK3/PSA protein:\n- Retrieved [3]: hK2 and PSA kallikreins comparison\n- Retrieved [6]: PSA promoter-driven androgen-inducible expression\n- Retrieved [17]: KLK3 gene variant Ile179Thr\n- Retrieved [24]: Grape-derived resveratrol decreases PSA expression\n- Retrieved [25]: PSA promoter androgen-independent expression\n- Retrieved [26]: Recombinant PSA and hK2 cross-reactivity\n- Retrieved [32]: Steroid hormone regulation of hK2 and PSA\n- Retrieved [33]: KLK3 alternative splicing\n- Retrieved [36]: PSA negatively regulated by p53\n- Retrieved [37]: PSA as biomarker review (mechanistic content)\n- Retrieved [43]: Biochemistry of PSA\n- Retrieved [44]: FOXM1 regulates PSA gene transcription\n- Retrieved [45]: Galectin-3 cleavage by PSA\n- Retrieved [50]: PSA and hK2 forms in LNCaP cells\n- Retrieved [52]: PSA activated by KLK2\n- Retrieved [53]: PSA regulates AR expression\n- Retrieved [64]: KLK3 locus resequencing\n- Retrieved [67]: PSA protein effects on prostate cancer growth\n- Retrieved [68]: Peptides modulating KLK2 and KLK3 activity\n- Retrieved [69]: KLK3 mutations and male infertility\n- Retrieved [76]: MRGBP promotes AR-mediated transactivation of KLK3\n- Retrieved [77]: α2,3-sialyl N-glycosylated PSA\n- Retrieved [78]: Antiangiogenic properties of PSA\n- Retrieved [99]: Birth-and-death of KLK3 and KLK2 in primates\n\nGene2pubmed KEEP:\n- [8]: Enzymatic activity of PSA and reactions with proteinase inhibitors\n- [9]: Human PSA structural and functional similarity with serine proteases\n- [10]: PSA is an IGFBP-3 protease in seminal plasma\n- [12]: Molecular cloning of human PSA cDNA\n- [17]: New human kallikrein gene family\n- [18]: Altered glycosylation pattern of PSA from normal vs tumor\n- [19]: miR-99 family suppresses PSA expression\n- [21]: RNF6-induced ubiquitination regulates AR and PSA\n- [27]: Characterization of precursor of PSA, activation by trypsin and hK2\n- [28]: NF-κB activates PSA expression\n\nEXCLUDE (alias collisions/unrelated):\n- PSA-NCAM papers (neural cell adhesion molecule) — alias collision\n- APS adapter protein papers — alias collision\n- APS kinase (adenosine phosphosulfate) papers — alias collision\n- Astragalus polysaccharide (APS) papers — alias collision\n- Antiphospholipid syndrome (APS) papers — alias collision\n- Autoimmune polyendocrine syndrome (APS) papers — alias collision\n- pSa plasmid papers — alias collision\n- Leishmania PSA papers — symbol collision\n- Puromycin-sensitive aminopeptidase (PSA/NPEPPS) paper [95] — different protein\n- Pisum sativum agglutinin (PSA) paper — collision\n- Bacteroides fragilis PSA polysaccharide — collision\n- Plant APS/ApS papers — collision\n- Upadacitinib/PsA (psoriatic arthritis) papers — different \"PsA\"\n- BioPlex interactome papers — too generic, no KLK3-specific mechanism described\n- GWAS/screening/clinical papers without mechanistic content\n\n```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 1986,\n      \"finding\": \"KLK3/PSA was determined to be a serine protease with chymotrypsin-like activity. The complete amino acid sequence (240 residues) revealed the catalytic triad (His-41, Asp-96, Ser-192) characteristic of serine proteases, and the protein was shown to cleave insulin A and B chains and other substrates preferentially after hydrophobic residues (Tyr, Leu, Val, Phe), with Km ~15.3 mM and kcat ~0.075 s⁻¹ for a chymotryptic substrate. Activity was inhibited by PMSF, DFP, TLCK, aprotinin, and Zn²⁺.\",\n      \"method\": \"Amino acid sequencing, chromogenic substrate in vitro enzymatic assays, protease inhibitor profiling\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — complete sequence determination plus in vitro enzymatic reconstitution with kinetic parameters; foundational paper replicated broadly\",\n      \"pmids\": [\"2422647\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1987,\n      \"finding\": \"The cDNA encoding KLK3/PSA was cloned from a human prostate cDNA library. The 1415-nucleotide insert codes for a signal peptide, a short propeptide, and a mature protein of 237 amino acid residues (Mr 26,089 non-glycosylated), with one N-linked glycosylation site. Sequence analysis confirmed extensive homology with kallikrein-family proteases.\",\n      \"method\": \"cDNA library screening, nucleotide sequencing\",\n      \"journal\": \"FEBS letters\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — primary molecular cloning establishing gene structure; foundational and widely replicated\",\n      \"pmids\": [\"2436946\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1990,\n      \"finding\": \"Purified KLK3/PSA displayed chymotrypsin-like enzymatic activity and cleaved semenogelin and semenogelin-related proteins in a rapid and characteristic pattern (establishing semenogelin as its primary seminal substrate). Active PSA formed SDS-stable 1:1 molar complexes with alpha1-antichymotrypsin (ACT) by cleaving ACT at the same position as chymotrypsin cleaves ACT. PSA also formed complexes with alpha2-macroglobulin (which encapsulates PSA epitopes). Approximately one-third of purified PSA was enzymatically inactive due to internal cleavage C-terminal of Lys145.\",\n      \"method\": \"Aprotinin-Sepharose purification, in vitro enzymatic assay with semenogelin substrates, SDS-PAGE complex analysis, complex formation rate measurement\",\n      \"journal\": \"European journal of biochemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — direct in vitro reconstitution of enzyme-substrate and enzyme-inhibitor interactions; foundational, widely cited\",\n      \"pmids\": [\"1702714\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1992,\n      \"finding\": \"KLK3/PSA was identified as an IGFBP-3 protease in seminal plasma. Purified PSA cleaved 125I-labeled IGFBP-3 with a cleavage pattern identical to that of whole seminal plasma, while IGFBP-2 and IGFBP-4 were not degraded. Cleavage of IGFBP-3 by PSA markedly reduced binding affinity of the fragments to IGF-I but not IGF-II.\",\n      \"method\": \"In vitro protease assay with purified PSA and radiolabeled IGFBP-3, Western ligand blot\",\n      \"journal\": \"The Journal of clinical endocrinology and metabolism\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — direct in vitro reconstitution with purified proteins; identifies IGFBP-3 as a specific PSA substrate\",\n      \"pmids\": [\"1383255\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1995,\n      \"finding\": \"Biochemical characterization confirmed that the mature PSA (237 amino acids, single-chain glycoprotein) is a serine protease with restricted chymotrypsin-like activity responsible for gel dissolution in ejaculated semen by proteolysis of the gel-forming proteins semenogelin I, semenogelin II, and fibronectin. In semen ~two-thirds of PSA is enzymatically active; the remaining 30–40% is inactive due to internal cleavage(s). A small fraction in semen is complexed to protein C inhibitor. PSA complexed to alpha1-antichymotrypsin (ACT) is the predominant molecular form in serum, though complex formation between purified proteins in vitro is slow.\",\n      \"method\": \"Biochemical characterization, in vitro protease assays, immunoassay, complex formation analysis\",\n      \"journal\": \"Scandinavian journal of clinical and laboratory investigation. Supplementum\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — multiple orthogonal biochemical methods defining substrates and inhibitor complexes in seminal and serum contexts\",\n      \"pmids\": [\"7544481\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1995,\n      \"finding\": \"Recombinant PSA and hK2 (KLK2) were expressed in eukaryotic cells (Semliki Forest Virus system). Testing of 18 monoclonal anti-PSA IgGs revealed that 5 cross-reacted with recombinant hK2 with identical affinities, while 13 recognized PSA alone. Cross-reactive antibodies bind a region exposed when PSA is complexed to alpha1-antichymotrypsin, identifying the ACT-complex-exposed epitope as the shared PSA/hK2 region.\",\n      \"method\": \"Recombinant protein expression, monoclonal antibody binding assays, epitope mapping\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — recombinant protein production with systematic antibody panel testing; single study\",\n      \"pmids\": [\"7544581\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1997,\n      \"finding\": \"Recombinant pro-PSA (zymogen, 244 residues with 7-amino-acid N-terminal propiece Ala-Pro-Leu-Ile-Leu-Ser-Arg) was expressed in E. coli and refolded. Pro-PSA was activated by trypsin (at 50:1 weight ratio) via cleavage at the Arg-Ile peptide bond releasing the propeptide to generate active PSA. Pro-PSA was also activated by recombinant human glandular kallikrein (hK2/KLK2) and by partially purified seminal plasma proteases. Active recombinant PSA was inhibited by alpha1-antichymotrypsin (forming ~100 kDa equimolar complex) but, unlike hK2, PSA failed to activate single-chain urokinase-type plasminogen activator.\",\n      \"method\": \"Recombinant protein expression and refolding, in vitro activation assays, chromogenic substrate enzymatic assays, SDS-PAGE\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — reconstitution of zymogen activation with purified enzymes; multiple activating proteases tested; foundational\",\n      \"pmids\": [\"9261179\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1998,\n      \"finding\": \"hK2 (KLK2) rapidly converts the inactive precursor proPSA to active PSA in biochemical studies, suggesting a key in vivo regulatory role for hK2 in controlling PSA protease activity. Both PSA and hK2 are produced as secretory proteins by the same prostate epithelial cells; the potent trypsin-like activity of hK2 contrasts with the weak chymotrypsin-like activity of PSA.\",\n      \"method\": \"In vitro protease activation assays, immunoassays, comparative biochemical characterization\",\n      \"journal\": \"Critical reviews in clinical laboratory sciences\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — review integrating prior in vitro biochemical findings; activation mechanism corroborated by multiple studies\",\n      \"pmids\": [\"9759557\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1999,\n      \"finding\": \"Trans-resveratrol (at 4-day treatment) reduced intracellular and secreted PSA protein levels in LNCaP cells by ~80% without changing androgen receptor (AR) expression levels (measured by Western blot and radioligand binding with [³H]R1881), indicating that resveratrol down-regulates PSA by an AR-independent mechanism.\",\n      \"method\": \"Cell-based treatment assay, Western blot for AR and PSA, radioligand binding assay\",\n      \"journal\": \"Anticancer research\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 — single cell-line study, mechanistic pathway of AR-independence shown but downstream pathway not identified\",\n      \"pmids\": [\"10769659\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"Two cis-elements in the 5.8 kb PSA promoter drive androgen-independent PSA expression: (1) a 440-bp androgen-responsive element enhancer core (AREc) in which AR binds AREs under androgen-deprived conditions (shown by mutation analysis and supershift experiments), and (2) a 150-bp pN/H region containing a 17-bp RI site bound by a 45-kDa cell-specific transcription factor (p45) identified by EMSA and UV cross-linking, driving AR-independent promoter activity. Juxtaposing both elements produced a chimeric supra-PSA promoter with 2–3-fold higher activity than wild-type.\",\n      \"method\": \"Promoter deletion/mutation analysis, DNase I footprinting, linker scan mutagenesis, EMSA, UV cross-linking, transient transfection\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 — multiple orthogonal methods (footprinting, mutagenesis, EMSA, UV cross-linking) in two cell lines identifying distinct cis-elements\",\n      \"pmids\": [\"11006269\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"KLK3/PSA and KLK2/hK2 are regulated by androgens and progestins in breast cancer cell lines. In BT-474 cells, synthetic androgen mibolerone was the most potent stimulator for both kallikreins, followed by the synthetic progestin norgestrel. Estradiol induced small but significant amounts of hK2 and PSA in BT-474 cells, supporting cross-talk between estrogen and androgen receptor signaling pathways. BT-474 cells express ~500–1000-fold more hK2 than T-47D cells, revealing cell-type-specific differential regulation of the two genes.\",\n      \"method\": \"Time-resolved fluorometric immunoassays (cell culture supernatants), steroid hormone treatment of breast cancer cell lines\",\n      \"journal\": \"Breast cancer research and treatment\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 — secreted protein measurement without direct mechanistic pathway elucidation\",\n      \"pmids\": [\"10832596\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"Unusual alternative splicing of KLK3 involving inclusion of intronic sequences adjacent to exon 1 generates a novel transcript encoding a protein called PSA-linked molecule (PSA-LM). PSA-LM shares only the signal peptide with PSA; the mature protein is entirely different and bears no similarity to the kallikrein family. PSA-LM is expressed in secretory epithelial cells of the prostate and is up-regulated by androgenic stimulation, similarly to PSA.\",\n      \"method\": \"RT-PCR, sequence analysis, immunohistochemistry, androgen stimulation experiments\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — novel transcript characterized with androgen regulation confirmed experimentally\",\n      \"pmids\": [\"11834722\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"Wild-type p53 strongly repressed PSA promoter-driven transcription and PSA protein secretion in LNCaP prostate cancer cells, while dominant-negative p53 mutants stimulated PSA expression. cDNA microarray showed a ~4-fold increase in PSA mRNA when p53 was suppressed. The inhibitory effect of wild-type p53 was abolished by trichostatin A (HDAC inhibitor), implicating histone deacetylation in the negative regulation of PSA promoter activity by p53.\",\n      \"method\": \"cDNA microarray, transient transfection with wild-type and dominant-negative p53 constructs, ELISA for secreted PSA, trichostatin A treatment\",\n      \"journal\": \"Oncogene\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — multiple approaches (microarray, OE of p53 variants, pharmacologic HDAC inhibition) in single lab\",\n      \"pmids\": [\"11791186\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"PSA protein (enzymatically inactive forms produced by transfection of human and rat prostate cancer cell lines) did not alter growth kinetics in vitro and did not change xenograft doubling times in vivo, demonstrating that the PSA protein itself, independent of enzymatic activity, does not significantly affect prostate cancer cell growth or angiogenesis in these models.\",\n      \"method\": \"Stable transfection of multiple prostate cancer cell lines with PSA gene, in vitro growth assays, xenograft in vivo models, fluorescent peptide substrate assay for enzymatic activity\",\n      \"journal\": \"The Prostate\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — multiple cell lines and in vivo models tested; single lab\",\n      \"pmids\": [\"12746846\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"N-glycan characterization of PSA from normal seminal plasma versus LNCaP tumor cells revealed distinct glycosylation patterns. Normal PSA glycans are sialylated biantennary complex structures (mono- and disialylated). LNCaP (tumor-derived) PSA glycans are neutral (non-sialylated), have higher fucose content (including alpha1-2 fucosylation forming the H2 epitope absent in normal PSA), and increased GalNAc (65% vs. 25%). These carbohydrate differences allow distinction between PSA from normal and tumor origins.\",\n      \"method\": \"N-glycan sequencing, mass spectrometry, immunoprecipitation\",\n      \"journal\": \"Glycobiology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — MS-based structural glycan characterization with orthogonal sequencing; directly defines PTM differences\",\n      \"pmids\": [\"12626390\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"KLK2 is the protease responsible for activating PSA in biologically relevant models. PSA was activated by KLK2 when PSA- and KLK2-expressing cells were in physical contact, through co-conditioned media, and in vivo in subcutaneous co-inoculation xenografts (reduced free-to-total PSA ratio indicating more active PSA). Double-transgenic mice expressing both PSA and KLK2 in the prostate produced more active PSA than single-PSA transgenics. Active PSA expression alone over 2 years did not induce PIN or prostate cancer in transgenic mice.\",\n      \"method\": \"Cell co-culture, co-conditioned media assays, xenograft co-inoculation, double-transgenic mouse models, PSA activity assays\",\n      \"journal\": \"The Prostate\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 — multiple orthogonal in vitro and in vivo models confirming KLK2-mediated PSA activation; strong evidence\",\n      \"pmids\": [\"20058238\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"PSA localizes to nuclei of androgen-stimulated LNCaP and C4-2B prostate cancer cells (demonstrated by immunofluorescence and subcellular fractionation). Stable shRNA or transient siRNA knockdown of PSA resulted in reduced AR protein and mRNA levels in C4-2B and VCaP cells, revealing a feedback loop where PSA positively controls AR expression. This regulation was independent of Src activation and did not appear to involve integrin-mediated Src signaling.\",\n      \"method\": \"Immunofluorescence, subcellular fractionation, shRNA/siRNA knockdown, immunoblotting, real-time PCR\",\n      \"journal\": \"The Prostate\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — nuclear localization confirmed by two methods; loss-of-function with defined AR mRNA/protein phenotype in multiple cell lines; single lab\",\n      \"pmids\": [\"21956655\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"The miR-99 family (miR-99a, -99b, miR-100) suppresses PSA expression in prostate cancer cells. Transfection of these miRNAs inhibited PSA expression and cell growth. Mechanistically, the miR-99 family targets SMARCA5 (a chromatin-remodeling factor), and PSA is posttranscriptionally regulated at least in part through repression of SMARCA5.\",\n      \"method\": \"miRNA transfection, microarray, polyribosomal loading analysis, quantitative RT-PCR, computational target prediction with experimental validation\",\n      \"journal\": \"Cancer research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — miRNA transfection with target validation by multiple transcriptomic methods; indirect regulation through SMARCA5\",\n      \"pmids\": [\"21212412\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"Tyrosine-107 phosphorylated galectin-3 is resistant to cleavage by PSA. PSA (a chymotrypsin-like serine protease) cleaves galectin-3 after Tyr-107, disrupting galectin-3 multivalency while preserving carbohydrate binding activity. When galectin-3 Tyr-107 is phosphorylated by c-Abl kinase, PSA-mediated cleavage at that site is blocked, linking c-Abl activity with resistance to PSA proteolysis in prostate cells.\",\n      \"method\": \"In vitro cleavage assays with purified PSA, site-directed phosphorylation by c-Abl, Western blot, loss-of-PTEN cell models\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — direct in vitro protease assay identifying substrate and showing PTM-dependent cleavage resistance; single lab\",\n      \"pmids\": [\"22232548\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"PSA antiangiogenic activity is dependent on its enzymatic activity. Inactive PSA isoforms lack antiangiogenic activity in a HUVEC tube formation model. Inhibition of PSA enzymatic activity by a monoclonal antibody or small molecule inhibitors abolishes the antiangiogenic effect, while a peptide that stimulates PSA enzymatic activity enhances the antiangiogenic effect. Gene expression changes in HUVECs treated with PSA were opposite to those associated with tube formation.\",\n      \"method\": \"HUVEC tube formation assay, enzymatic activity modulation (antibody, small molecule inhibitors, stimulatory peptide), gene expression analysis\",\n      \"journal\": \"Scandinavian journal of clinical and laboratory investigation\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — functional antiangiogenic assay with multiple pharmacological tools linking enzymatic activity to the phenotype; single lab\",\n      \"pmids\": [\"19551556\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"NF-κB activates PSA gene expression. By expressing dominant-active MEKK1, TNF-alpha treatment, or overexpression of p50/p65, NF-κB was shown to activate a transcriptional regulatory element of the KLK3 gene. DNase I footprinting identified four NF-κB binding sites in the PSA core enhancer. Androgen-independent prostate cancer xenografts had higher constitutive NF-κB binding activity than androgen-dependent counterparts.\",\n      \"method\": \"Transient transfection with dominant-active MEKK1 or p50/p65, TNF-alpha treatment, DNase I footprinting, NF-κB binding assay in xenografts\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 — footprinting identifies binding sites; multiple genetic and pharmacological activators tested; in vivo xenograft correlation\",\n      \"pmids\": [\"11909978\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"FOXM1 directly binds to Forkhead kinase (FHK) binding motifs in the PSA promoter/enhancer regions (identified by ChIP-PCR) and regulates KLK3 gene transcription. Androgen-independent C4-2 cells have more FOXM1 binding sites engaged than androgen-dependent LNCaP cells. Depletion of FOXM1 by small-molecule inhibitors significantly improved suppression of PSA transcription by the anti-AR agent Cadosax.\",\n      \"method\": \"ChIP-PCR, FOXM1 inhibitor treatment, combinatorial knockdown with anti-AR agent, gene expression analysis\",\n      \"journal\": \"Oncotarget\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — ChIP identifies direct binding; pharmacological loss-of-function with defined transcriptional phenotype; single lab\",\n      \"pmids\": [\"28199985\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"MRGBP promotes androgen receptor (AR)-mediated transactivation of KLK3 (PSA) and TMPRSS2. MRGBP associates with AR binding regions of these genes during androgen treatment. MRGBP interacts with MRG15 and TIP60 in prostate cancer cells. AR stimulation enhanced H3K4me1/me3 at AR binding regions; MRGBP is recruited to active gene regions via MRG15 binding to H3K4me1/3, then promotes recruitment of TIP60 and acetylation of histone variant H2A.Z at AR binding sites, which increases AR occupancy of these regions.\",\n      \"method\": \"ChIP, Co-immunoprecipitation, siRNA knockdown, gene expression analysis, histone modification mapping\",\n      \"journal\": \"Biochimica et biophysica acta. Gene regulatory mechanisms\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — ChIP and Co-IP with mechanistic histone modification pathway defined; single lab\",\n      \"pmids\": [\"30076933\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"HER2/ERBB3 pathway signaling stabilizes AR protein levels and optimizes AR binding to promoter/enhancer regions of androgen-regulated genes including KLK3/PSA. The dual EGFR/HER2 inhibitor PKI-166 reduced AR transcriptional activity and PSA expression. Effects were mediated by HER2/ERBB3, not EGFR, and involved kinases other than Akt.\",\n      \"method\": \"Small molecule kinase inhibition (PKI-166), genetic perturbation, AR-target gene expression analysis, AR binding to promoter regions\",\n      \"journal\": \"Cancer cell\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — pharmacological and genetic perturbation with AR occupancy at KLK3 promoter; single lab\",\n      \"pmids\": [\"15542435\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"RNF6, a ubiquitin E3 ligase, associates with AR and induces AR ubiquitination, promoting AR transcriptional activity and expression of a subset of AR target genes including KLK3/PSA. Knockdown of RNF6 or mutation of RNF6-induced ubiquitination acceptor sites on AR selectively altered expression of this AR target gene subset and diminished recruitment of AR and coactivators to androgen-responsive elements in the KLK3 regulatory region.\",\n      \"method\": \"Proteomic screen, Co-IP, ChIP, siRNA knockdown, ubiquitination assays, gene expression analysis in prostate cancer cells\",\n      \"journal\": \"Cancer cell\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — proteomic identification plus ChIP confirmation of AR binding at KLK3 AREs; ubiquitination site mutants tested; single lab\",\n      \"pmids\": [\"19345326\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"Evolutionary analysis of KLK3 and KLK2 across 22 primate species placed the KLK2-KLK3 duplication in the Catarrhini ancestor. dN/dS analysis provided evidence for adaptive evolution of KLK3 toward an expanded enzymatic spectrum with an effect on hydrolysis of the semen coagulum. Associations between mating system, number of semenogelin (SEMG) repeat units, and the number of functional KLK2 and KLK3 genes suggest that reproductive biology shaped KLK3 evolution.\",\n      \"method\": \"Comparative genomics, dN/dS calculation, phylogenetic analysis across 22 primate species\",\n      \"journal\": \"Genome biology and evolution\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 4 — computational/comparative evolutionary analysis without direct functional reconstitution\",\n      \"pmids\": [\"23204305\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"KLK3/PSA is a member of the expanded human kallikrein gene family (15 members on chromosome 19q13). PSA was established as a potent inhibitor of angiogenesis, and NES1/KLK10 was identified as a breast cancer tumor suppressor. Multiple newly identified kallikrein-like genes are regulated by steroid hormones.\",\n      \"method\": \"Gene family characterization by sequence analysis, hormone regulation studies, angiogenesis assay\",\n      \"journal\": \"Trends in endocrinology and metabolism: TEM\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3–4 — review integrating gene discovery data; antiangiogenic finding mentioned without detailed mechanistic assay description in this paper\",\n      \"pmids\": [\"10675891\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"Genetic variations in the KLK3 coding region correlate with male infertility. Five SNPs (rs266881, rs174776, rs266875, rs35192866, rs1810020) were significantly associated with increased infertility risk in 875 infertile versus 290 fertile men. Since PSA/KLK3 is the chief executor of semenogelin fragmentation and semen liquefaction, and PSA levels correlate with sperm motility, these coding variants likely disrupt PSA enzymatic activity required for semen liquefaction.\",\n      \"method\": \"Complete coding region resequencing, genetic association study in a large ethnically matched cohort\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 4 — genetic association without direct functional validation of variant effects on enzymatic activity\",\n      \"pmids\": [\"28894123\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"KLK3/PSA is a kallikrein-family serine protease with chymotrypsin-like specificity (catalytic triad His-41, Asp-96, Ser-192) secreted as a zymogen (proPSA) that is activated primarily by KLK2 through cleavage of its 7-amino-acid propeptide; active PSA cleaves its principal seminal substrates semenogelin I/II and fibronectin to liquefy semen, also cleaves IGFBP-3 (reducing IGF-I binding) and galectin-3 (at Tyr-107, blocked by c-Abl-mediated phosphorylation), and exerts antiangiogenic activity dependent on its enzymatic activity; in circulation, active PSA is rapidly sequestered by forming SDS-stable 1:1 complexes with alpha1-antichymotrypsin or encapsulating complexes with alpha2-macroglobulin; KLK3 transcription is driven by androgen receptor binding to AREs in its promoter/enhancer, with additional AR-independent inputs from NF-κB (binding four sites in the PSA core enhancer), FOXM1 (binding FHK motifs), and a 45-kDa cell-specific factor (binding the pN/H RI element), while being negatively regulated by p53 (via histone deacetylation) and the miR-99 family (via SMARCA5 repression); MRGBP/MRG15/TIP60 promote H2A.Z acetylation at AR binding regions to enhance AR occupancy and KLK3 expression, RNF6-mediated AR ubiquitination similarly promotes AR recruitment to KLK3 regulatory elements, and HER2/ERBB3 signaling stabilizes AR protein to sustain KLK3 expression; tumor-derived PSA displays a distinct glycosylation pattern (neutral, hyperfucosylated N-glycans with H2 epitope) compared to normal PSA (sialylated biantennary structures); and PSA localizes to the nucleus of androgen-stimulated prostate cancer cells where it positively regulates AR mRNA and protein levels in a feedback loop.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"KLK3 (prostate-specific antigen, PSA) is a secreted serine protease with chymotrypsin-like specificity that functions primarily in seminal fluid liquefaction by cleaving semenogelin I/II and fibronectin, and also cleaves galectin-3 at Tyr-107 to disrupt its multivalency [PMID:7544481, PMID:22232548]. KLK3 is secreted as an inactive zymogen (proPSA) that is activated extracellularly by the trypsin-like protease KLK2, a regulatory step validated in vitro, in xenografts, and in double-transgenic mice [PMID:9759557, PMID:20058238]. Transcription of KLK3 is driven by androgen receptor binding to androgen-responsive elements in its promoter, co-activated by FOXM1 and the MRGBP/MRG15/TIP60 epigenetic complex, and repressed by p53 through histone deacetylation [PMID:11006269, PMID:28199985, PMID:30076933, PMID:11791186]. The enzymatic activity of PSA is required for its antiangiogenic effect on endothelial cells, and in androgen-stimulated prostate cancer cells PSA localizes to the nucleus where it positively regulates AR mRNA and protein levels [PMID:19551556, PMID:21956655].\",\n  \"teleology\": [\n    {\n      \"year\": 1995,\n      \"claim\": \"Establishing KLK3 as a chymotrypsin-like serine protease that dissolves the seminal coagulum resolved the primary physiological function of PSA beyond its role as a serum biomarker.\",\n      \"evidence\": \"Biochemical characterization of purified PSA showing proteolysis of semenogelin I/II and fibronectin, and complex formation with ACT and alpha-2-macroglobulin\",\n      \"pmids\": [\"7544481\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Full substrate repertoire in vivo not defined\", \"Relative contribution of PSA vs. other seminal proteases to liquefaction not quantified\"]\n    },\n    {\n      \"year\": 1998,\n      \"claim\": \"Identifying KLK2 as the activator of proPSA answered how the inactive zymogen is converted to active enzyme, revealing a kallikrein cascade in the prostate.\",\n      \"evidence\": \"In vitro reconstitution of proPSA activation by recombinant KLK2\",\n      \"pmids\": [\"9759557\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether additional proteases contribute to proPSA activation in vivo\", \"Structural basis of KLK2 recognition of the proPSA pro-peptide\"]\n    },\n    {\n      \"year\": 2000,\n      \"claim\": \"Mapping androgen-responsive and androgen-independent cis-elements in the KLK3 promoter established the transcriptional logic governing prostate-specific, androgen-regulated PSA expression.\",\n      \"evidence\": \"Deletion/mutation analysis, DNase I footprinting, EMSA, and reporter assays in LNCaP and C4-2 cells identifying AREc and a prostate-specific 17-bp RI element bound by a 45-kDa factor\",\n      \"pmids\": [\"11006269\", \"10232600\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Identity of the 45-kDa prostate cell-specific transcription factor (p45) not determined\", \"Chromatin architecture at the endogenous locus not resolved\"]\n    },\n    {\n      \"year\": 2000,\n      \"claim\": \"Demonstrating that p53 represses KLK3 transcription via histone deacetylation connected tumor suppressor signaling to PSA regulation and explained PSA elevation upon p53 loss.\",\n      \"evidence\": \"Dominant-negative p53 increases PSA secretion 4–8-fold in LNCaP cells; wild-type p53 represses PSA promoter activity and trichostatin A abolishes repression\",\n      \"pmids\": [\"11791186\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether p53 acts directly on the KLK3 promoter or through intermediary factors\", \"In vivo validation in animal models lacking\"]\n    },\n    {\n      \"year\": 2009,\n      \"claim\": \"Showing that PSA's antiangiogenic activity requires its enzymatic activity linked the protease function to a potential tumor-suppressive paracrine role.\",\n      \"evidence\": \"HUVEC tube formation assays with enzymatically inactive PSA isoforms, blocking antibodies, small-molecule inhibitors, and activating peptides\",\n      \"pmids\": [\"19551556\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"The substrate cleaved by PSA to generate the antiangiogenic signal is unknown\", \"In vivo antiangiogenic relevance not demonstrated\"]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"Multi-model validation of KLK2 as the physiological activator of PSA strengthened the in vitro finding with in vivo and transgenic evidence.\",\n      \"evidence\": \"Cell co-incubation, xenograft co-inoculation altering free-to-total PSA ratio, and prostate-targeted PSA/KLK2 double-transgenic mice producing more active PSA\",\n      \"pmids\": [\"20058238\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Quantitative contribution of KLK2 versus other candidate activating proteases in human prostate tissue\"]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"Discovery that PSA localizes to the nucleus and positively regulates AR mRNA/protein levels revealed an unexpected feedback loop between PSA and the androgen receptor.\",\n      \"evidence\": \"Immunofluorescence, subcellular fractionation, and shRNA/siRNA knockdown reducing AR levels in C4-2B and VCaP cells\",\n      \"pmids\": [\"21956655\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism by which nuclear PSA regulates AR transcription is undefined\", \"Whether enzymatic activity is required for this nuclear function\", \"Not independently replicated\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Identification of galectin-3 as a PSA substrate, with c-Abl phosphorylation blocking cleavage, established a regulated protease-substrate interaction with implications for galectin-3-mediated signaling.\",\n      \"evidence\": \"In vitro cleavage of galectin-3 at Tyr-107 by PSA; c-Abl phosphorylation of galectin-3 renders it resistant to cleavage\",\n      \"pmids\": [\"22232548\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"In vivo relevance of galectin-3 cleavage by PSA not demonstrated\", \"Downstream biological consequences of galectin-3 cleavage in prostate tissue unknown\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Demonstration that FOXM1 directly binds the KLK3 promoter and drives PSA transcription, particularly in androgen-independent cells, identified a mechanism for sustained PSA expression in castration-resistant prostate cancer.\",\n      \"evidence\": \"ChIP-PCR of FOXM1 binding sites in LNCaP and C4-2 cells, FOXM1 depletion reducing PSA reporter activity\",\n      \"pmids\": [\"28199985\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether FOXM1 cooperates with or substitutes for AR at the KLK3 promoter\", \"No in vivo confirmation\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Elucidation of the MRGBP/MRG15/TIP60 epigenetic axis that promotes AR-mediated KLK3 transactivation through H2A.Z acetylation provided a chromatin-level mechanism for androgen-regulated gene activation.\",\n      \"evidence\": \"ChIP, co-immunoprecipitation, and shRNA knockdown showing MRGBP recruitment via MRG15-H3K4me binding, TIP60-mediated H2A.Z acetylation, and enhanced AR occupancy\",\n      \"pmids\": [\"30076933\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Genome-wide specificity of this complex for KLK3 versus other AR targets\", \"Structural details of complex assembly unknown\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The substrate responsible for PSA's antiangiogenic activity, the mechanism by which nuclear PSA regulates AR expression, and whether PSA enzymatic activity is required for its nuclear functions remain unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"Antiangiogenic substrate unknown\", \"Nuclear PSA mechanism undefined\", \"No structural model of PSA–substrate complexes beyond semenogelins\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0140096\", \"supporting_discovery_ids\": [0, 1, 9, 10]},\n      {\"term_id\": \"GO:0016787\", \"supporting_discovery_ids\": [0, 9]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005576\", \"supporting_discovery_ids\": [0, 5, 7]},\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [8]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"GO:0140096\", \"supporting_discovery_ids\": []},\n      {\"term_id\": \"R-HSA-392499\", \"supporting_discovery_ids\": [0, 1, 7]},\n      {\"term_id\": \"R-HSA-1474165\", \"supporting_discovery_ids\": [0, 15]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\n      \"KLK2\",\n      \"LGALS3\",\n      \"AR\",\n      \"FOXM1\",\n      \"MRGBP\",\n      \"SERPINA3\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```\n\n--- ROUND 2 (R2/R3, augmented corpus) ---\n\n```json\n{\n  \"mechanistic_narrative\": \"KLK3 encodes prostate-specific antigen (PSA), a kallikrein-family serine protease with chymotrypsin-like specificity (catalytic triad His-41, Asp-96, Ser-192) that is secreted as an inactive zymogen (proPSA) and activated principally by KLK2-mediated cleavage of its 7-amino-acid propeptide [PMID:9261179, PMID:20058238]. Active PSA liquefies the seminal coagulum by cleaving semenogelin I, semenogelin II, and fibronectin, and also proteolyzes IGFBP-3 (reducing IGF-I binding) and galectin-3 (at Tyr-107, blocked by c-Abl phosphorylation), while exerting enzymatic-activity-dependent antiangiogenic effects [PMID:1702714, PMID:1383255, PMID:22232548, PMID:19551556]. In circulation, active PSA is rapidly sequestered by alpha1-antichymotrypsin (forming SDS-stable 1:1 complexes) or alpha2-macroglobulin; tumor-derived PSA displays distinct neutral, hyperfucosylated N-glycans compared to the sialylated biantennary structures of normal seminal PSA [PMID:1702714, PMID:12626390]. KLK3 transcription is androgen receptor-driven, with AR occupancy enhanced by MRGBP/MRG15/TIP60-mediated H2A.Z acetylation and RNF6-mediated AR ubiquitination, and further modulated by NF-κB, FOXM1, p53-dependent histone deacetylation, and miR-99 family repression of SMARCA5 [PMID:11006269, PMID:11909978, PMID:30076933, PMID:19345326, PMID:11791186, PMID:21212412].\",\n  \"teleology\": [\n    {\n      \"year\": 1986,\n      \"claim\": \"Establishing that PSA is a serine protease with chymotrypsin-like specificity resolved the molecular identity of this abundant prostatic secretory protein, revealing its catalytic triad and substrate preferences.\",\n      \"evidence\": \"Complete amino acid sequencing plus in vitro kinetic assays with chromogenic substrates and protease inhibitor profiling\",\n      \"pmids\": [\"2422647\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Three-dimensional structure not yet determined\", \"Physiological substrates not yet identified\", \"Activation mechanism unknown\"]\n    },\n    {\n      \"year\": 1987,\n      \"claim\": \"Cloning the KLK3 cDNA established its gene structure — signal peptide, propeptide, and mature chain — and placed it within the kallikrein protease family.\",\n      \"evidence\": \"cDNA library screening from human prostate with nucleotide sequencing\",\n      \"pmids\": [\"2436946\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Zymogen activation mechanism not characterized\", \"Genomic organization and regulatory elements undefined\"]\n    },\n    {\n      \"year\": 1990,\n      \"claim\": \"Identifying semenogelin as the principal PSA substrate and demonstrating SDS-stable complex formation with alpha1-antichymotrypsin defined the physiological function of PSA in semen liquefaction and established why circulating PSA is predominantly ACT-complexed.\",\n      \"evidence\": \"In vitro enzymatic assay with purified PSA and seminal substrates; SDS-PAGE analysis of PSA-ACT and PSA-alpha2-macroglobulin complexes\",\n      \"pmids\": [\"1702714\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanism of zymogen activation in vivo unresolved\", \"Semenogelin cleavage sites not fully mapped\"]\n    },\n    {\n      \"year\": 1992,\n      \"claim\": \"Demonstration that PSA specifically cleaves IGFBP-3 (but not IGFBP-2 or -4), reducing IGF-I binding, expanded its substrate repertoire beyond semenogelin to a growth-factor regulatory axis.\",\n      \"evidence\": \"In vitro protease assay with purified PSA and radiolabeled IGFBP-3; Western ligand blot\",\n      \"pmids\": [\"1383255\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"In vivo relevance of IGFBP-3 cleavage by PSA not established\", \"Whether IGF signaling is altered in prostatic tissue by PSA-mediated IGFBP-3 cleavage unknown\"]\n    },\n    {\n      \"year\": 1997,\n      \"claim\": \"Reconstituting zymogen activation in vitro showed that proPSA is activated by cleavage of its 7-residue propeptide by trypsin or KLK2, establishing the proteolytic cascade governing PSA maturation.\",\n      \"evidence\": \"Recombinant pro-PSA expression in E. coli, refolding, activation by purified trypsin and recombinant KLK2, SDS-PAGE and chromogenic assays\",\n      \"pmids\": [\"9261179\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Relative contribution of KLK2 versus other proteases in vivo not quantified\", \"Spatial and temporal regulation of activation in prostatic ducts unresolved\"]\n    },\n    {\n      \"year\": 2000,\n      \"claim\": \"Mapping of the KLK3 promoter/enhancer revealed that androgen-independent transcription is driven by both an ARE-containing enhancer core (bound by AR even without ligand) and a pN/H element bound by a 45-kDa cell-specific factor, explaining how PSA expression persists in androgen-deprived settings.\",\n      \"evidence\": \"Promoter deletion and linker scan mutagenesis, DNase I footprinting, EMSA, UV cross-linking in LNCaP and PC-3 cells\",\n      \"pmids\": [\"11006269\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Identity of p45 transcription factor unknown\", \"Chromatin context of enhancer elements not addressed\"]\n    },\n    {\n      \"year\": 2002,\n      \"claim\": \"Identification of four NF-κB binding sites in the PSA core enhancer and demonstration that p53 represses KLK3 through histone deacetylation revealed AR-independent transcriptional regulators that modulate PSA expression, particularly in androgen-independent prostate cancer.\",\n      \"evidence\": \"DNase I footprinting for NF-κB sites; p50/p65 overexpression and TNF-α treatment; wild-type/dominant-negative p53 transfection with trichostatin A rescue in LNCaP cells\",\n      \"pmids\": [\"11909978\", \"11791186\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether NF-κB and p53 pathways interact at the PSA enhancer unknown\", \"Direct AR-NF-κB cooperativity at the locus not tested\"]\n    },\n    {\n      \"year\": 2003,\n      \"claim\": \"Glycan structural analysis revealed that tumor-derived PSA carries neutral, hyperfucosylated N-glycans (including H2 epitope) while normal seminal PSA is sialylated, establishing a molecular basis for distinguishing cancer-derived PSA.\",\n      \"evidence\": \"Mass spectrometry-based N-glycan sequencing of PSA from seminal plasma and LNCaP cells\",\n      \"pmids\": [\"12626390\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether glycan differences arise from altered glycosyltransferase expression in tumors not determined\", \"Clinical diagnostic utility of glycoform discrimination not validated\"]\n    },\n    {\n      \"year\": 2009,\n      \"claim\": \"Demonstrating that PSA antiangiogenic activity requires enzymatic activity (abolished by inhibitory antibodies and small molecules, enhanced by a stimulatory peptide) linked PSA's protease function to an extracellular biological process beyond semen liquefaction.\",\n      \"evidence\": \"HUVEC tube formation assay with active vs. inactive PSA isoforms, pharmacological modulation of enzymatic activity, gene expression profiling\",\n      \"pmids\": [\"19551556\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Substrate(s) responsible for antiangiogenic effect not identified\", \"In vivo antiangiogenic relevance not confirmed in animal models\"]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"In vivo confirmation that KLK2 is the physiological activator of proPSA — using co-culture, xenograft co-inoculation, and double-transgenic mice — validated the KLK2→PSA proteolytic cascade and showed that active PSA alone does not initiate prostate neoplasia.\",\n      \"evidence\": \"Cell co-culture, conditioned media, subcutaneous xenograft co-inoculation, PSA/KLK2 double-transgenic mice monitored for 2 years\",\n      \"pmids\": [\"20058238\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Other prostatic proteases that may contribute to proPSA activation not excluded\", \"Whether loss of PSA activation affects fertility in mice not tested\"]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"Discovery that PSA localizes to the nucleus in androgen-stimulated prostate cancer cells and positively regulates AR mRNA/protein levels revealed a feedback loop between PSA and its own transcriptional driver.\",\n      \"evidence\": \"Immunofluorescence and subcellular fractionation for nuclear localization; shRNA/siRNA knockdown of PSA with AR mRNA/protein quantification in C4-2B and VCaP cells\",\n      \"pmids\": [\"21956655\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism by which nuclear PSA regulates AR transcription unknown\", \"Whether nuclear PSA retains enzymatic activity not determined\", \"Not independently replicated outside the originating lab\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Showing that c-Abl-mediated phosphorylation of galectin-3 at Tyr-107 blocks PSA cleavage at that site identified a phospho-switch that regulates PSA substrate accessibility in prostate cells.\",\n      \"evidence\": \"In vitro cleavage assays with purified PSA and galectin-3, site-directed c-Abl phosphorylation, Western blot\",\n      \"pmids\": [\"22232548\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"In vivo relevance of galectin-3 cleavage by PSA in tumor microenvironment not established\", \"Other phosphorylation-regulated PSA substrates not investigated\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Elucidation of the MRGBP/MRG15/TIP60 chromatin remodeling axis showed that H2A.Z acetylation at AR binding regions of KLK3 enhances AR occupancy, providing a chromatin-level mechanism for AR-dependent KLK3 transcription.\",\n      \"evidence\": \"ChIP for histone modifications and factor occupancy, co-immunoprecipitation for MRGBP-MRG15-TIP60 complex, siRNA knockdown with gene expression readout in prostate cancer cells\",\n      \"pmids\": [\"30076933\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether H2A.Z acetylation is specific to KLK3 or shared across all AR target genes not resolved\", \"Structural basis of MRGBP-MRG15-TIP60 complex assembly unknown\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"Major unresolved questions include: the identity and mechanism of the 45-kDa cell-specific factor (p45) binding the pN/H element; the substrate(s) mediating PSA's antiangiogenic activity; the mechanism by which nuclear PSA regulates AR expression; and whether KLK3 coding variants directly impair enzymatic activity to cause male infertility.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No structural model of proPSA activation by KLK2 exists\", \"Functional validation of infertility-associated KLK3 coding SNPs not performed\", \"Nuclear import signal and nuclear interactome of PSA uncharacterized\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0140096\", \"supporting_discovery_ids\": [0, 2, 3, 4, 6, 18]},\n      {\"term_id\": \"GO:0016787\", \"supporting_discovery_ids\": [0, 2, 3, 4]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005576\", \"supporting_discovery_ids\": [2, 4, 14]},\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [16]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-1474165\", \"supporting_discovery_ids\": [2, 4, 15, 27]},\n      {\"term_id\": \"R-HSA-392499\", \"supporting_discovery_ids\": [0, 3, 6, 18]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\n      \"KLK2\",\n      \"SERPINA3\",\n      \"IGFBP3\",\n      \"LGALS3\",\n      \"SEMG1\",\n      \"SEMG2\",\n      \"AR\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```"}