{"gene":"PDE6D","run_date":"2026-06-10T05:19:53","timeline":{"discoveries":[{"year":1998,"finding":"PDE6D (delta subunit) is able to detach the photoreceptor cGMP phosphodiesterase PDE6 (alpha-beta-gamma complex) partially from bovine rod outer segment membranes under physiological conditions, demonstrating a role in membrane association/dissociation of PDE6.","method":"Biochemical membrane extraction assay with purified protein","journal":"Genomics","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct biochemical assay with purified components, single lab, foundational characterization","pmids":["9570951"],"is_preprint":false},{"year":2012,"finding":"PDE6D mediates ciliary targeting of the prenylated protein INPP5E through a prenyl-binding-dependent mechanism; ARL13B (not ARL2 or ARL3) facilitates this targeting, and ARL13B, INPP5E, PDE6D, and CEP164 form a distinct functional network involved in Joubert syndrome and nephronophthisis.","method":"Co-immunoprecipitation, protein-protein interaction assays, ciliary localization studies in cell lines, genetic analysis","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 2 / Strong — reciprocal Co-IP, localization experiments, genetic validation with disease-causing missense mutations, replicated across multiple orthogonal approaches","pmids":["23150559"],"is_preprint":false},{"year":2014,"finding":"A homozygous splice-site mutation in PDE6D reduces its binding to prenylated INPP5E, causing failure of INPP5E to localize to primary cilia in patient fibroblasts and tissues; additionally, mutant PDE6D is unable to bind GTP-bound ARL3, which normally acts as a cargo-release factor for PDE6D-bound INPP5E.","method":"Exome sequencing, proteomic analysis, binding assays, zebrafish knockdown rescue experiments, immunofluorescence in patient fibroblasts","journal":"Human mutation","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal methods (binding assays, patient cell localization, zebrafish KD rescue), disease mutation validation","pmids":["24166846"],"is_preprint":false},{"year":2014,"finding":"PDE6D (PrBP/δ) regulates trafficking of isoprenylated proteins PDE6 and GRK1 from photoreceptor inner segments to outer segments; Pde6d knockout mice show nearly undetectable PDE6 and GRK1 in cones and reduced photopic ERG b-wave amplitudes. Knockout of Unc119 partially reverses the GRK1 transport defect in Pde6d−/− cones, indicating interdependence of isoprenylated and acylated protein transport pathways.","method":"Pde6d knockout mouse, Pde6d/Unc119 double knockout mouse, ERG, immunolocalization","journal":"Advances in experimental medicine and biology","confidence":"High","confidence_rationale":"Tier 2 / Moderate — clean KO mouse with defined cellular phenotype, double KO epistasis, multiple readouts","pmids":["24664735"],"is_preprint":false},{"year":2015,"finding":"PDE6D binds preferentially to the C-terminal prenyl moiety (rather than the N-terminal RCC1-like domain) of RPGR in mammalian cells; this interaction depends on the amino acid adjacent to the prenylation motif, providing a mechanism for specificity of PDE6D–prenylated protein interactions.","method":"Co-immunoprecipitation in mammalian cells, domain mapping, prenylation-dependent binding assays","journal":"EMBO reports","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — reciprocal binding assays with domain mutants, single lab, two orthogonal approaches","pmids":["26553938"],"is_preprint":false},{"year":2016,"finding":"RPGR is a prenylated cargo of PDE6D for ciliary targeting; RPGR prenylation is required for its ciliary localization, and ablation of PDE6D blocks ciliary targeting of RPGR. Two independent ciliary targeting signals exist in RPGR: one within the N-terminal RCC1-like domain and one near the C-terminal prenylation site.","method":"PDE6D knockdown/ablation, ciliary localization assays, prenylation mutant analysis, immunofluorescence","journal":"Biology open","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — loss-of-function with defined localization phenotype, mutant mapping, single lab","pmids":["27493202"],"is_preprint":false},{"year":2013,"finding":"PDE6D was identified as the direct molecular binding target of anecortave acetate (AA) and anecortave desacetate (AdesA) in human trabecular meshwork cells; overexpression of PDE6D in mouse eyes caused elevated intraocular pressure, which was reversed by topical application of AA or AdesA.","method":"Yeast three-hybrid screen, competitive Y3H, co-immunoprecipitation, surface plasmon resonance, mouse eye overexpression model","journal":"ACS chemical biology","confidence":"High","confidence_rationale":"Tier 1–2 / Strong — SPR binding validation, Y3H, Co-IP, and in vivo functional assay in mouse eyes, multiple orthogonal methods","pmids":["23301619"],"is_preprint":false},{"year":2019,"finding":"PDE6D acts as a trafficking chaperone for K-Ras4B; ARL2-assisted unloading of K-Ras from PDE6D in the perinuclear area is required for correct K-Ras localization and activity. Small molecule inhibitors of the PDE6D prenyl-binding pocket selectively disrupt K-Ras (but not H-Ras) membrane organization and inhibit K-Ras-dependent signaling and cancer cell proliferation.","method":"Small molecule inhibitor (Deltaflexin-1/-2) treatment, Ras membrane organization assays, antiproliferative assays in cancer cell lines","journal":"ACS omega","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — cell-based functional assays with selective inhibitors and K-Ras vs H-Ras selectivity controls, single lab","pmids":["31956834"],"is_preprint":false},{"year":2022,"finding":"Stabilizing the KRAS:PDE6D complex (via RAS point mutations increasing affinity for PDE6D) redirects RAS to the cytoplasm and primary cilium and inhibits oncogenic RAS/ERK signaling. Fragment binders at the KRAS:PDE6D interface were identified by SPR screening and cocrystal structures. KRAS:PDE6D stoichiometric ratios vary across cell lines.","method":"Rationally designed RAS point mutations, SPR fragment screening, cocrystal structures, RAS/ERK signaling assays, localization studies","journal":"Journal of medicinal chemistry","confidence":"High","confidence_rationale":"Tier 1 / Moderate — cocrystal structures, mutagenesis, SPR, and functional signaling assays in single study with multiple orthogonal methods","pmids":["35104933"],"is_preprint":false},{"year":2022,"finding":"PDE6D mediates membrane localization of RAS proteins; inhibition of PDE6D by DW0254 blocks RAS localization to the plasma membrane, which is associated with RAC inhibition through a PI3K/AKT-dependent mechanism in acute lymphoblastic leukemia cells.","method":"Chemical proteomics, biophysical binding assays, RAS/RAC localization assays, PI3K/AKT pathway analysis in leukemia cell lines","journal":"Blood cancer journal","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — chemical proteomics target identification, biophysical validation, pathway epistasis, single lab","pmids":["35422065"],"is_preprint":false},{"year":2023,"finding":"PDE6D mediates ciliary trafficking of novel prenylated cargo proteins NIM1K (serine/threonine kinase) and UBL3; both localize inside cilia in a prenylation-dependent manner. UBL3 also localizes in vesicle-like structures around the cilium base and associates with proteins regulating small extracellular vesicles and ciliogenesis, suggesting a role in sorting proteins to the photoreceptor outer segment.","method":"Affinity proteomics (prenylated cargo purification), co-immunoprecipitation, ciliary localization assays with prenylation mutants, immunofluorescence","journal":"Cells","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — affinity proteomics with prenylation-dependent localization validation, single lab, two orthogonal approaches","pmids":["36672247"],"is_preprint":false},{"year":2024,"finding":"PKG2-mediated phosphorylation of Ser181 on K-Ras lowers K-Ras binding to PDE6D; combining a PDE6D inhibitor (Deltaflexin3) with the PKG2 activator Sildenafil more potently inhibits PDE6D/K-Ras binding, cancer cell proliferation, and microtumor growth than either agent alone.","method":"Biochemical binding assays, phosphorylation site mutagenesis (Ser181), cell proliferation assays, microtumor growth assays, combination treatment","journal":"Journal of medicinal chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — phosphorylation-dependent binding assay with functional readout, single lab, multiple assays","pmids":["38758695"],"is_preprint":false},{"year":2025,"finding":"Low-dose metformin inhibits castration-resistant prostate cancer progression by regulating PDE6D, inducing alterations in purine metabolism and activating the cGMP/PKG pathway; cells with high PDE6D expression show greater resistance to metformin, and combining metformin with PDE6D inhibitor TMX-4100 enhances tumor inhibition.","method":"Mouse xenograft model, metabolomic-seq, transcriptomic-seq, PDE6D inhibitor TMX-4100 combination treatment","journal":"Cancer letters","confidence":"Low","confidence_rationale":"Tier 3 / Weak — omics-based inference with in vivo combination treatment, mechanism linking PDE6D to cGMP/PKG not directly validated at molecular level","pmids":["40216151"],"is_preprint":false},{"year":2025,"finding":"A genetically encoded farnesylated tetra-peptide inhibitor (SNAP-STI) efficiently blocks PDE6D binding of farnesylated cargo. Inhibition of K-Ras membrane anchorage and K-RasG12C-dependent MAPK-signaling by SNAP-STI is weak (negative finding), consistent with PDE6D knockdown data, supporting that PDE6D is not a suitable surrogate target for efficient inhibition of K-Ras membrane anchorage and MAPK activity.","method":"Genetically encoded inhibitor design, direct comparison with small molecule inhibitors, K-Ras membrane anchorage assays, MAPK signaling assays, PDE6D knockdown","journal":"bioRxiv","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple orthogonal functional assays, direct comparison with established inhibitors, preprint not yet peer-reviewed","pmids":["bio_10.1101_2025.09.29.679187"],"is_preprint":true}],"current_model":"PDE6D is a prenyl-binding chaperone protein that solubilizes and traffics farnesylated/geranylgeranylated cargo proteins—including K-Ras4B, INPP5E, RPGR, GRK1, PDE6 catalytic subunits, NIM1K, and UBL3—from cytosolic compartments to their target membranes (plasma membrane for Ras) or primary cilia; GTP-bound ARL3 acts as a cargo-release factor at the destination, and ARL13B facilitates ciliary delivery of specific cargoes, while PKG2-mediated phosphorylation of Ser181 on K-Ras modulates its affinity for PDE6D."},"narrative":{"mechanistic_narrative":"PDE6D is a prenyl-binding chaperone that solubilizes farnesylated and geranylgeranylated cargo proteins from membranes and shuttles them between cytosolic compartments and their functional destinations, including the plasma membrane and the primary cilium [PMID:9570951, PMID:23150559, PMID:31956834]. It was first defined as the delta subunit able to extract the photoreceptor cGMP phosphodiesterase PDE6 from rod outer segment membranes, establishing its capacity to control membrane association of prenylated proteins [PMID:9570951]. PDE6D engages cargo through the C-terminal prenyl moiety, with specificity dictated by the residue adjacent to the prenylation motif, and this prenyl-binding-dependent recognition underlies trafficking of INPP5E, RPGR, GRK1, PDE6, and the additional ciliary cargoes NIM1K and UBL3 [PMID:23150559, PMID:26553938, PMID:27493202, PMID:36672247]. Cargo release at the destination is driven by GTP-bound ARL3 and ARL2, which unload PDE6D-bound proteins in the perinuclear/ciliary region, while ARL13B facilitates ciliary delivery of specific cargoes such as INPP5E [PMID:23150559, PMID:24166846, PMID:31956834]. In photoreceptors PDE6D directs PDE6 and GRK1 from inner to outer segments, and loss of PDE6D depletes these proteins from cones and impairs the photopic ERG response, with the acyl-binding chaperone UNC119 acting in an interdependent transport pathway [PMID:24664735]. A homozygous splice-site mutation that abolishes both prenylated-cargo and ARL3 binding causes failure of INPP5E ciliary localization, linking PDE6D to a ciliopathy network with ARL13B, INPP5E, and CEP164 implicated in Joubert syndrome and nephronophthisis [PMID:23150559, PMID:24166846]. PDE6D also chaperones K-Ras4B to the plasma membrane, and disrupting its prenyl-binding pocket pharmacologically or by phosphorylation of K-Ras Ser181 lowers K-Ras membrane organization and oncogenic RAS/ERK signaling, defining PDE6D as a candidate anticancer target [PMID:31956834, PMID:35104933, PMID:38758695].","teleology":[{"year":1998,"claim":"Established that PDE6D can remove a prenylated phototransduction enzyme from membranes, the founding observation of its solubilizing/chaperone activity.","evidence":"Biochemical membrane extraction of PDE6 from bovine rod outer segments with purified delta subunit","pmids":["9570951"],"confidence":"Medium","gaps":["Did not define the structural basis of prenyl recognition","Did not identify a cargo-release mechanism","Limited to a single photoreceptor cargo"]},{"year":2012,"claim":"Showed PDE6D traffics prenylated INPP5E to the cilium and embedded it in a ciliopathy network, connecting the chaperone to ciliary cargo delivery.","evidence":"Co-IP, ciliary localization, and genetic analysis in cell lines","pmids":["23150559"],"confidence":"High","gaps":["Role of ARL13B vs ARL2/ARL3 in release step not fully resolved here","Generalization to other ciliary cargoes untested"]},{"year":2013,"claim":"Identified PDE6D as the direct target of anecortave acetate and linked its overexpression to elevated intraocular pressure, defining a druggable pocket and a non-trafficking disease context.","evidence":"Yeast three-hybrid, SPR, Co-IP, and mouse eye overexpression model","pmids":["23301619"],"confidence":"High","gaps":["Mechanism linking PDE6D level to intraocular pressure not defined","Cargo responsible for the IOP phenotype not identified"]},{"year":2014,"claim":"Demonstrated in a knockout mouse that PDE6D is required for inner-to-outer segment transport of PDE6 and GRK1 and that it works interdependently with the acyl-chaperone UNC119.","evidence":"Pde6d and Pde6d/Unc119 double knockout mice with ERG and immunolocalization","pmids":["24664735"],"confidence":"High","gaps":["Molecular basis of UNC119/PDE6D pathway crosstalk not resolved","Cone-specific vulnerability mechanism unclear"]},{"year":2014,"claim":"A patient splice-site mutation established that loss of both prenyl-cargo and GTP-ARL3 binding causes INPP5E ciliary mislocalization, mechanistically defining ARL3 as the cargo-release factor in disease.","evidence":"Exome sequencing, binding assays, patient fibroblast immunofluorescence, zebrafish knockdown rescue","pmids":["24166846"],"confidence":"High","gaps":["Full spectrum of cargoes affected in patients not mapped","Tissue-specific consequences beyond cilia not defined"]},{"year":2015,"claim":"Defined the determinant of cargo specificity by showing PDE6D binds the C-terminal prenyl moiety and that the residue adjacent to the prenylation motif tunes affinity.","evidence":"Co-IP, domain mapping, and prenylation-dependent binding assays in mammalian cells (RPGR)","pmids":["26553938"],"confidence":"Medium","gaps":["Affinity rules not validated across the full cargo repertoire","Single lab, single cargo"]},{"year":2016,"claim":"Confirmed RPGR as a prenylation-dependent PDE6D cargo for ciliary targeting and revealed dual ciliary targeting signals, refining how cargo reaches the cilium.","evidence":"PDE6D ablation, prenylation mutant analysis, and ciliary localization assays","pmids":["27493202"],"confidence":"Medium","gaps":["Interplay between RCC1-domain signal and prenyl signal not mechanistically dissected","Release step for RPGR not characterized"]},{"year":2019,"claim":"Extended PDE6D chaperone function to oncogenic K-Ras4B and showed ARL2-assisted perinuclear unloading is required for correct localization, nominating the prenyl pocket as an anticancer target.","evidence":"Deltaflexin inhibitors, Ras membrane organization and antiproliferation assays in cancer lines","pmids":["31956834"],"confidence":"Medium","gaps":["Selectivity over other prenylated GTPases incompletely defined","Durability of signaling inhibition unclear"]},{"year":2022,"claim":"Provided structural and functional evidence that stabilizing rather than blocking the KRAS:PDE6D complex redirects RAS away from the membrane and inhibits oncogenic signaling, introducing an alternative pharmacologic strategy.","evidence":"RAS point mutations, SPR fragment screening, cocrystal structures, and RAS/ERK assays","pmids":["35104933"],"confidence":"High","gaps":["Cell-line variability in KRAS:PDE6D stoichiometry not explained","Translation of complex-stabilizers to cells not established"]},{"year":2022,"claim":"Linked PDE6D-dependent RAS membrane localization to downstream RAC inhibition via PI3K/AKT in leukemia, broadening the signaling consequences of PDE6D blockade.","evidence":"Chemical proteomics, biophysical binding, and pathway analysis with DW0254 in ALL cells","pmids":["35422065"],"confidence":"Medium","gaps":["Directness of PDE6D-to-RAC link not fully resolved","Single disease context"]},{"year":2023,"claim":"Identified NIM1K and UBL3 as new prenylation-dependent ciliary cargoes, expanding the PDE6D cargo repertoire and connecting it to extracellular vesicle/ciliogenesis sorting.","evidence":"Affinity proteomics of prenylated cargo, Co-IP, and prenylation-mutant ciliary localization","pmids":["36672247"],"confidence":"Medium","gaps":["Functional roles of NIM1K and UBL3 in cilia not defined","Release factors for the new cargoes not tested"]},{"year":2024,"claim":"Showed PKG2 phosphorylation of K-Ras Ser181 lowers PDE6D affinity and that combining a PDE6D inhibitor with a PKG2 activator cooperatively suppresses K-Ras binding and tumor growth, revealing a regulatable affinity switch.","evidence":"Phosphosite mutagenesis, binding assays, and microtumor growth combination assays","pmids":["38758695"],"confidence":"Medium","gaps":["In vivo relevance of the combination beyond microtumors untested","Effect on non-Ras cargoes not assessed"]},{"year":2025,"claim":"Linked PDE6D to metformin response and the cGMP/PKG axis in castration-resistant prostate cancer, suggesting PDE6D as a metabolic-therapy modifier.","evidence":"Xenograft model with metabolomic/transcriptomic profiling and PDE6D inhibitor combination","pmids":["40216151"],"confidence":"Low","gaps":["Molecular link between PDE6D and cGMP/PKG not directly validated","Omics-based inference without mechanistic dissection","Causality versus correlation not established"]},{"year":2025,"claim":"A farnesylated tetra-peptide inhibitor blocked PDE6D cargo binding but only weakly affected K-Ras membrane anchorage and MAPK signaling, challenging PDE6D as a surrogate target for K-Ras inhibition.","evidence":"Genetically encoded inhibitor, knockdown comparison, membrane anchorage and MAPK assays (preprint)","pmids":["bio_10.1101_2025.09.29.679187"],"confidence":"Medium","gaps":["Preprint, not yet peer-reviewed","Discrepancy with small-molecule inhibitor studies unresolved","Context-dependence of K-Ras dependence on PDE6D unclear"]},{"year":null,"claim":"The structural and kinetic logic governing how distinct cargoes are differentially loaded, retained, and released by PDE6D across tissues, and whether PDE6D is a tractable target for K-Ras-driven cancers, remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No unified affinity/release model across cargoes","Conflicting evidence on PDE6D as a K-Ras anticancer target","Tissue-specific cargo dependencies not mapped"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0008289","term_label":"lipid binding","supporting_discovery_ids":[0,4,5,7,10]},{"term_id":"GO:0140104","term_label":"molecular carrier activity","supporting_discovery_ids":[1,2,3,7]},{"term_id":"GO:0140313","term_label":"molecular sequestering activity","supporting_discovery_ids":[0,7]}],"localization":[{"term_id":"GO:0005929","term_label":"cilium","supporting_discovery_ids":[1,5,10]},{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[0,7]},{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[7,9]}],"pathway":[{"term_id":"R-HSA-9609507","term_label":"Protein localization","supporting_discovery_ids":[1,2,3,5,10]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[7,8,9]}],"complexes":[],"partners":["KRAS","INPP5E","RPGR","ARL3","ARL13B","GRK1","PDE6","ARL2"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"O43924","full_name":"Retinal rod rhodopsin-sensitive cGMP 3',5'-cyclic phosphodiesterase subunit delta","aliases":["Protein p17"],"length_aa":150,"mass_kda":17.4,"function":"Promotes the release of prenylated target proteins from cellular membranes (PubMed:9712853). Modulates the activity of prenylated or palmitoylated Ras family members by regulating their subcellular location (PubMed:22002721, PubMed:23698361). Required for normal ciliary targeting of farnesylated target proteins, such as INPP5E (PubMed:24166846). Required for RAB28 localization to the cone cell outer segments in the retina (By similarity). Modulates the subcellular location of target proteins by acting as a GTP specific dissociation inhibitor (GDI) (By similarity). Increases the affinity of ARL3 for GTP by several orders of magnitude. Stabilizes ARL3-GTP by decreasing the nucleotide dissociation rate (By similarity)","subcellular_location":"Cytoplasm, cytosol; Cytoplasmic vesicle membrane; Cytoplasm, cytoskeleton, cilium basal body","url":"https://www.uniprot.org/uniprotkb/O43924/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/PDE6D","classification":"Not Classified","n_dependent_lines":1,"n_total_lines":1208,"dependency_fraction":0.0008278145695364238},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[{"gene":"ARL3","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/search/PDE6D","total_profiled":1310},"omim":[{"mim_id":"620513","title":"UNC119 LIPID-BINDING CHAPERONE B; UNC119B","url":"https://www.omim.org/entry/620513"},{"mim_id":"615665","title":"JOUBERT SYNDROME 22; JBTS22","url":"https://www.omim.org/entry/615665"},{"mim_id":"614848","title":"CENTROSOMAL PROTEIN, 164-KD; CEP164","url":"https://www.omim.org/entry/614848"},{"mim_id":"613037","title":"INOSITOL POLYPHOSPHATE-5-PHOSPHATASE, 72-KD; INPP5E","url":"https://www.omim.org/entry/613037"},{"mim_id":"608922","title":"ADP-RIBOSYLATION FACTOR-LIKE GTPase 13B; ARL13B","url":"https://www.omim.org/entry/608922"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Supported","locations":[{"location":"Vesicles","reliability":"Supported"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/PDE6D"},"hgnc":{"alias_symbol":["JBTS22"],"prev_symbol":[]},"alphafold":{"accession":"O43924","domains":[{"cath_id":"2.70.50.40","chopping":"2-148","consensus_level":"high","plddt":96.4923,"start":2,"end":148}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/O43924","model_url":"https://alphafold.ebi.ac.uk/files/AF-O43924-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-O43924-F1-predicted_aligned_error_v6.png","plddt_mean":96.25},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=PDE6D","jax_strain_url":"https://www.jax.org/strain/search?query=PDE6D"},"sequence":{"accession":"O43924","fasta_url":"https://rest.uniprot.org/uniprotkb/O43924.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/O43924/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/O43924"}},"corpus_meta":[{"pmid":"23150559","id":"PMC_23150559","title":"ARL13B, PDE6D, and CEP164 form a functional network for INPP5E ciliary targeting.","date":"2012","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/23150559","citation_count":199,"is_preprint":false},{"pmid":"24166846","id":"PMC_24166846","title":"A homozygous PDE6D mutation in Joubert syndrome impairs targeting of farnesylated INPP5E protein to the primary cilium.","date":"2014","source":"Human mutation","url":"https://pubmed.ncbi.nlm.nih.gov/24166846","citation_count":110,"is_preprint":false},{"pmid":"31956834","id":"PMC_31956834","title":"PDE6D Inhibitors with a New Design Principle Selectively Block K-Ras Activity.","date":"2019","source":"ACS omega","url":"https://pubmed.ncbi.nlm.nih.gov/31956834","citation_count":35,"is_preprint":false},{"pmid":"9570951","id":"PMC_9570951","title":"Characterization of human and mouse rod cGMP phosphodiesterase delta subunit (PDE6D) and chromosomal localization of the human gene.","date":"1998","source":"Genomics","url":"https://pubmed.ncbi.nlm.nih.gov/9570951","citation_count":29,"is_preprint":false},{"pmid":"38758695","id":"PMC_38758695","title":"An Improved PDE6D Inhibitor Combines with Sildenafil To Inhibit KRAS Mutant Cancer Cell Growth.","date":"2024","source":"Journal of medicinal chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/38758695","citation_count":19,"is_preprint":false},{"pmid":"35104933","id":"PMC_35104933","title":"Stabilization of the RAS:PDE6D Complex Is a Novel Strategy to Inhibit RAS Signaling.","date":"2022","source":"Journal of medicinal chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/35104933","citation_count":18,"is_preprint":false},{"pmid":"27493202","id":"PMC_27493202","title":"RPGR, a prenylated retinal ciliopathy protein, is targeted to cilia in a prenylation- and PDE6D-dependent manner.","date":"2016","source":"Biology 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Cilia.","date":"2023","source":"Cells","url":"https://pubmed.ncbi.nlm.nih.gov/36672247","citation_count":7,"is_preprint":false},{"pmid":"30423442","id":"PMC_30423442","title":"A novel PDE6D mutation in a patient with Joubert syndrome type 22 (JBTS22).","date":"2018","source":"European journal of medical genetics","url":"https://pubmed.ncbi.nlm.nih.gov/30423442","citation_count":6,"is_preprint":false},{"pmid":"10452952","id":"PMC_10452952","title":"Molecular characterization and mapping of canine cGMP-phosphodiesterase delta subunit (PDE6D).","date":"1999","source":"Gene","url":"https://pubmed.ncbi.nlm.nih.gov/10452952","citation_count":5,"is_preprint":false},{"pmid":"12927076","id":"PMC_12927076","title":"Analysis of PDE6D and PDE6G genes for generalised progressive retinal atrophy (gPRA) mutations in dogs.","date":"2003","source":"Genetics, selection, evolution : GSE","url":"https://pubmed.ncbi.nlm.nih.gov/12927076","citation_count":5,"is_preprint":false},{"pmid":"24664735","id":"PMC_24664735","title":"Unc119 gene deletion partially rescues the GRK1 transport defect of Pde6d (- /-) cones.","date":"2014","source":"Advances in experimental medicine and biology","url":"https://pubmed.ncbi.nlm.nih.gov/24664735","citation_count":4,"is_preprint":false},{"pmid":"41611882","id":"PMC_41611882","title":"Computational identification and mechanistic characterization of natural product binders targeting the PDE6D prenyl binding tunnel.","date":"2026","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/41611882","citation_count":2,"is_preprint":false},{"pmid":"42034571","id":"PMC_42034571","title":"The role of PDE6D in trafficking KRAS.","date":"2026","source":"Biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/42034571","citation_count":1,"is_preprint":false},{"pmid":null,"id":"bio_10.1101_2025.09.29.679187","title":"Development of a genetically encoded and potent PDE6D inhibitor","date":"2025-09-30","source":"bioRxiv","url":"https://doi.org/10.1101/2025.09.29.679187","citation_count":0,"is_preprint":true}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":10456,"output_tokens":3513,"usd":0.042031,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":11132,"output_tokens":4474,"usd":0.083755,"stage2_stop_reason":"end_turn"},"total_usd":0.125786,"stage1_batch_id":"msgbatch_013a8chtv3AWyTqv4z4sEF4C","stage2_batch_id":"msgbatch_01AHsuW63vinsvuTgzmQ3n62","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 1998,\n      \"finding\": \"PDE6D (delta subunit) is able to detach the photoreceptor cGMP phosphodiesterase PDE6 (alpha-beta-gamma complex) partially from bovine rod outer segment membranes under physiological conditions, demonstrating a role in membrane association/dissociation of PDE6.\",\n      \"method\": \"Biochemical membrane extraction assay with purified protein\",\n      \"journal\": \"Genomics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct biochemical assay with purified components, single lab, foundational characterization\",\n      \"pmids\": [\"9570951\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"PDE6D mediates ciliary targeting of the prenylated protein INPP5E through a prenyl-binding-dependent mechanism; ARL13B (not ARL2 or ARL3) facilitates this targeting, and ARL13B, INPP5E, PDE6D, and CEP164 form a distinct functional network involved in Joubert syndrome and nephronophthisis.\",\n      \"method\": \"Co-immunoprecipitation, protein-protein interaction assays, ciliary localization studies in cell lines, genetic analysis\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — reciprocal Co-IP, localization experiments, genetic validation with disease-causing missense mutations, replicated across multiple orthogonal approaches\",\n      \"pmids\": [\"23150559\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"A homozygous splice-site mutation in PDE6D reduces its binding to prenylated INPP5E, causing failure of INPP5E to localize to primary cilia in patient fibroblasts and tissues; additionally, mutant PDE6D is unable to bind GTP-bound ARL3, which normally acts as a cargo-release factor for PDE6D-bound INPP5E.\",\n      \"method\": \"Exome sequencing, proteomic analysis, binding assays, zebrafish knockdown rescue experiments, immunofluorescence in patient fibroblasts\",\n      \"journal\": \"Human mutation\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal methods (binding assays, patient cell localization, zebrafish KD rescue), disease mutation validation\",\n      \"pmids\": [\"24166846\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"PDE6D (PrBP/δ) regulates trafficking of isoprenylated proteins PDE6 and GRK1 from photoreceptor inner segments to outer segments; Pde6d knockout mice show nearly undetectable PDE6 and GRK1 in cones and reduced photopic ERG b-wave amplitudes. Knockout of Unc119 partially reverses the GRK1 transport defect in Pde6d−/− cones, indicating interdependence of isoprenylated and acylated protein transport pathways.\",\n      \"method\": \"Pde6d knockout mouse, Pde6d/Unc119 double knockout mouse, ERG, immunolocalization\",\n      \"journal\": \"Advances in experimental medicine and biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — clean KO mouse with defined cellular phenotype, double KO epistasis, multiple readouts\",\n      \"pmids\": [\"24664735\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"PDE6D binds preferentially to the C-terminal prenyl moiety (rather than the N-terminal RCC1-like domain) of RPGR in mammalian cells; this interaction depends on the amino acid adjacent to the prenylation motif, providing a mechanism for specificity of PDE6D–prenylated protein interactions.\",\n      \"method\": \"Co-immunoprecipitation in mammalian cells, domain mapping, prenylation-dependent binding assays\",\n      \"journal\": \"EMBO reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal binding assays with domain mutants, single lab, two orthogonal approaches\",\n      \"pmids\": [\"26553938\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"RPGR is a prenylated cargo of PDE6D for ciliary targeting; RPGR prenylation is required for its ciliary localization, and ablation of PDE6D blocks ciliary targeting of RPGR. Two independent ciliary targeting signals exist in RPGR: one within the N-terminal RCC1-like domain and one near the C-terminal prenylation site.\",\n      \"method\": \"PDE6D knockdown/ablation, ciliary localization assays, prenylation mutant analysis, immunofluorescence\",\n      \"journal\": \"Biology open\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — loss-of-function with defined localization phenotype, mutant mapping, single lab\",\n      \"pmids\": [\"27493202\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"PDE6D was identified as the direct molecular binding target of anecortave acetate (AA) and anecortave desacetate (AdesA) in human trabecular meshwork cells; overexpression of PDE6D in mouse eyes caused elevated intraocular pressure, which was reversed by topical application of AA or AdesA.\",\n      \"method\": \"Yeast three-hybrid screen, competitive Y3H, co-immunoprecipitation, surface plasmon resonance, mouse eye overexpression model\",\n      \"journal\": \"ACS chemical biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Strong — SPR binding validation, Y3H, Co-IP, and in vivo functional assay in mouse eyes, multiple orthogonal methods\",\n      \"pmids\": [\"23301619\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"PDE6D acts as a trafficking chaperone for K-Ras4B; ARL2-assisted unloading of K-Ras from PDE6D in the perinuclear area is required for correct K-Ras localization and activity. Small molecule inhibitors of the PDE6D prenyl-binding pocket selectively disrupt K-Ras (but not H-Ras) membrane organization and inhibit K-Ras-dependent signaling and cancer cell proliferation.\",\n      \"method\": \"Small molecule inhibitor (Deltaflexin-1/-2) treatment, Ras membrane organization assays, antiproliferative assays in cancer cell lines\",\n      \"journal\": \"ACS omega\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — cell-based functional assays with selective inhibitors and K-Ras vs H-Ras selectivity controls, single lab\",\n      \"pmids\": [\"31956834\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"Stabilizing the KRAS:PDE6D complex (via RAS point mutations increasing affinity for PDE6D) redirects RAS to the cytoplasm and primary cilium and inhibits oncogenic RAS/ERK signaling. Fragment binders at the KRAS:PDE6D interface were identified by SPR screening and cocrystal structures. KRAS:PDE6D stoichiometric ratios vary across cell lines.\",\n      \"method\": \"Rationally designed RAS point mutations, SPR fragment screening, cocrystal structures, RAS/ERK signaling assays, localization studies\",\n      \"journal\": \"Journal of medicinal chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — cocrystal structures, mutagenesis, SPR, and functional signaling assays in single study with multiple orthogonal methods\",\n      \"pmids\": [\"35104933\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"PDE6D mediates membrane localization of RAS proteins; inhibition of PDE6D by DW0254 blocks RAS localization to the plasma membrane, which is associated with RAC inhibition through a PI3K/AKT-dependent mechanism in acute lymphoblastic leukemia cells.\",\n      \"method\": \"Chemical proteomics, biophysical binding assays, RAS/RAC localization assays, PI3K/AKT pathway analysis in leukemia cell lines\",\n      \"journal\": \"Blood cancer journal\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — chemical proteomics target identification, biophysical validation, pathway epistasis, single lab\",\n      \"pmids\": [\"35422065\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"PDE6D mediates ciliary trafficking of novel prenylated cargo proteins NIM1K (serine/threonine kinase) and UBL3; both localize inside cilia in a prenylation-dependent manner. UBL3 also localizes in vesicle-like structures around the cilium base and associates with proteins regulating small extracellular vesicles and ciliogenesis, suggesting a role in sorting proteins to the photoreceptor outer segment.\",\n      \"method\": \"Affinity proteomics (prenylated cargo purification), co-immunoprecipitation, ciliary localization assays with prenylation mutants, immunofluorescence\",\n      \"journal\": \"Cells\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — affinity proteomics with prenylation-dependent localization validation, single lab, two orthogonal approaches\",\n      \"pmids\": [\"36672247\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"PKG2-mediated phosphorylation of Ser181 on K-Ras lowers K-Ras binding to PDE6D; combining a PDE6D inhibitor (Deltaflexin3) with the PKG2 activator Sildenafil more potently inhibits PDE6D/K-Ras binding, cancer cell proliferation, and microtumor growth than either agent alone.\",\n      \"method\": \"Biochemical binding assays, phosphorylation site mutagenesis (Ser181), cell proliferation assays, microtumor growth assays, combination treatment\",\n      \"journal\": \"Journal of medicinal chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — phosphorylation-dependent binding assay with functional readout, single lab, multiple assays\",\n      \"pmids\": [\"38758695\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"Low-dose metformin inhibits castration-resistant prostate cancer progression by regulating PDE6D, inducing alterations in purine metabolism and activating the cGMP/PKG pathway; cells with high PDE6D expression show greater resistance to metformin, and combining metformin with PDE6D inhibitor TMX-4100 enhances tumor inhibition.\",\n      \"method\": \"Mouse xenograft model, metabolomic-seq, transcriptomic-seq, PDE6D inhibitor TMX-4100 combination treatment\",\n      \"journal\": \"Cancer letters\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — omics-based inference with in vivo combination treatment, mechanism linking PDE6D to cGMP/PKG not directly validated at molecular level\",\n      \"pmids\": [\"40216151\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"A genetically encoded farnesylated tetra-peptide inhibitor (SNAP-STI) efficiently blocks PDE6D binding of farnesylated cargo. Inhibition of K-Ras membrane anchorage and K-RasG12C-dependent MAPK-signaling by SNAP-STI is weak (negative finding), consistent with PDE6D knockdown data, supporting that PDE6D is not a suitable surrogate target for efficient inhibition of K-Ras membrane anchorage and MAPK activity.\",\n      \"method\": \"Genetically encoded inhibitor design, direct comparison with small molecule inhibitors, K-Ras membrane anchorage assays, MAPK signaling assays, PDE6D knockdown\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple orthogonal functional assays, direct comparison with established inhibitors, preprint not yet peer-reviewed\",\n      \"pmids\": [\"bio_10.1101_2025.09.29.679187\"],\n      \"is_preprint\": true\n    }\n  ],\n  \"current_model\": \"PDE6D is a prenyl-binding chaperone protein that solubilizes and traffics farnesylated/geranylgeranylated cargo proteins—including K-Ras4B, INPP5E, RPGR, GRK1, PDE6 catalytic subunits, NIM1K, and UBL3—from cytosolic compartments to their target membranes (plasma membrane for Ras) or primary cilia; GTP-bound ARL3 acts as a cargo-release factor at the destination, and ARL13B facilitates ciliary delivery of specific cargoes, while PKG2-mediated phosphorylation of Ser181 on K-Ras modulates its affinity for PDE6D.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"PDE6D is a prenyl-binding chaperone that solubilizes farnesylated and geranylgeranylated cargo proteins from membranes and shuttles them between cytosolic compartments and their functional destinations, including the plasma membrane and the primary cilium [#0, #1, #7]. It was first defined as the delta subunit able to extract the photoreceptor cGMP phosphodiesterase PDE6 from rod outer segment membranes, establishing its capacity to control membrane association of prenylated proteins [#0]. PDE6D engages cargo through the C-terminal prenyl moiety, with specificity dictated by the residue adjacent to the prenylation motif, and this prenyl-binding-dependent recognition underlies trafficking of INPP5E, RPGR, GRK1, PDE6, and the additional ciliary cargoes NIM1K and UBL3 [#1, #4, #5, #10]. Cargo release at the destination is driven by GTP-bound ARL3 and ARL2, which unload PDE6D-bound proteins in the perinuclear/ciliary region, while ARL13B facilitates ciliary delivery of specific cargoes such as INPP5E [#1, #2, #7]. In photoreceptors PDE6D directs PDE6 and GRK1 from inner to outer segments, and loss of PDE6D depletes these proteins from cones and impairs the photopic ERG response, with the acyl-binding chaperone UNC119 acting in an interdependent transport pathway [#3]. A homozygous splice-site mutation that abolishes both prenylated-cargo and ARL3 binding causes failure of INPP5E ciliary localization, linking PDE6D to a ciliopathy network with ARL13B, INPP5E, and CEP164 implicated in Joubert syndrome and nephronophthisis [#1, #2]. PDE6D also chaperones K-Ras4B to the plasma membrane, and disrupting its prenyl-binding pocket pharmacologically or by phosphorylation of K-Ras Ser181 lowers K-Ras membrane organization and oncogenic RAS/ERK signaling, defining PDE6D as a candidate anticancer target [#7, #8, #11].\",\n  \"teleology\": [\n    {\n      \"year\": 1998,\n      \"claim\": \"Established that PDE6D can remove a prenylated phototransduction enzyme from membranes, the founding observation of its solubilizing/chaperone activity.\",\n      \"evidence\": \"Biochemical membrane extraction of PDE6 from bovine rod outer segments with purified delta subunit\",\n      \"pmids\": [\"9570951\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Did not define the structural basis of prenyl recognition\", \"Did not identify a cargo-release mechanism\", \"Limited to a single photoreceptor cargo\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Showed PDE6D traffics prenylated INPP5E to the cilium and embedded it in a ciliopathy network, connecting the chaperone to ciliary cargo delivery.\",\n      \"evidence\": \"Co-IP, ciliary localization, and genetic analysis in cell lines\",\n      \"pmids\": [\"23150559\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Role of ARL13B vs ARL2/ARL3 in release step not fully resolved here\", \"Generalization to other ciliary cargoes untested\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Identified PDE6D as the direct target of anecortave acetate and linked its overexpression to elevated intraocular pressure, defining a druggable pocket and a non-trafficking disease context.\",\n      \"evidence\": \"Yeast three-hybrid, SPR, Co-IP, and mouse eye overexpression model\",\n      \"pmids\": [\"23301619\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanism linking PDE6D level to intraocular pressure not defined\", \"Cargo responsible for the IOP phenotype not identified\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Demonstrated in a knockout mouse that PDE6D is required for inner-to-outer segment transport of PDE6 and GRK1 and that it works interdependently with the acyl-chaperone UNC119.\",\n      \"evidence\": \"Pde6d and Pde6d/Unc119 double knockout mice with ERG and immunolocalization\",\n      \"pmids\": [\"24664735\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular basis of UNC119/PDE6D pathway crosstalk not resolved\", \"Cone-specific vulnerability mechanism unclear\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"A patient splice-site mutation established that loss of both prenyl-cargo and GTP-ARL3 binding causes INPP5E ciliary mislocalization, mechanistically defining ARL3 as the cargo-release factor in disease.\",\n      \"evidence\": \"Exome sequencing, binding assays, patient fibroblast immunofluorescence, zebrafish knockdown rescue\",\n      \"pmids\": [\"24166846\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Full spectrum of cargoes affected in patients not mapped\", \"Tissue-specific consequences beyond cilia not defined\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Defined the determinant of cargo specificity by showing PDE6D binds the C-terminal prenyl moiety and that the residue adjacent to the prenylation motif tunes affinity.\",\n      \"evidence\": \"Co-IP, domain mapping, and prenylation-dependent binding assays in mammalian cells (RPGR)\",\n      \"pmids\": [\"26553938\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Affinity rules not validated across the full cargo repertoire\", \"Single lab, single cargo\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Confirmed RPGR as a prenylation-dependent PDE6D cargo for ciliary targeting and revealed dual ciliary targeting signals, refining how cargo reaches the cilium.\",\n      \"evidence\": \"PDE6D ablation, prenylation mutant analysis, and ciliary localization assays\",\n      \"pmids\": [\"27493202\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Interplay between RCC1-domain signal and prenyl signal not mechanistically dissected\", \"Release step for RPGR not characterized\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Extended PDE6D chaperone function to oncogenic K-Ras4B and showed ARL2-assisted perinuclear unloading is required for correct localization, nominating the prenyl pocket as an anticancer target.\",\n      \"evidence\": \"Deltaflexin inhibitors, Ras membrane organization and antiproliferation assays in cancer lines\",\n      \"pmids\": [\"31956834\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Selectivity over other prenylated GTPases incompletely defined\", \"Durability of signaling inhibition unclear\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Provided structural and functional evidence that stabilizing rather than blocking the KRAS:PDE6D complex redirects RAS away from the membrane and inhibits oncogenic signaling, introducing an alternative pharmacologic strategy.\",\n      \"evidence\": \"RAS point mutations, SPR fragment screening, cocrystal structures, and RAS/ERK assays\",\n      \"pmids\": [\"35104933\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Cell-line variability in KRAS:PDE6D stoichiometry not explained\", \"Translation of complex-stabilizers to cells not established\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Linked PDE6D-dependent RAS membrane localization to downstream RAC inhibition via PI3K/AKT in leukemia, broadening the signaling consequences of PDE6D blockade.\",\n      \"evidence\": \"Chemical proteomics, biophysical binding, and pathway analysis with DW0254 in ALL cells\",\n      \"pmids\": [\"35422065\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Directness of PDE6D-to-RAC link not fully resolved\", \"Single disease context\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Identified NIM1K and UBL3 as new prenylation-dependent ciliary cargoes, expanding the PDE6D cargo repertoire and connecting it to extracellular vesicle/ciliogenesis sorting.\",\n      \"evidence\": \"Affinity proteomics of prenylated cargo, Co-IP, and prenylation-mutant ciliary localization\",\n      \"pmids\": [\"36672247\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Functional roles of NIM1K and UBL3 in cilia not defined\", \"Release factors for the new cargoes not tested\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Showed PKG2 phosphorylation of K-Ras Ser181 lowers PDE6D affinity and that combining a PDE6D inhibitor with a PKG2 activator cooperatively suppresses K-Ras binding and tumor growth, revealing a regulatable affinity switch.\",\n      \"evidence\": \"Phosphosite mutagenesis, binding assays, and microtumor growth combination assays\",\n      \"pmids\": [\"38758695\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"In vivo relevance of the combination beyond microtumors untested\", \"Effect on non-Ras cargoes not assessed\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Linked PDE6D to metformin response and the cGMP/PKG axis in castration-resistant prostate cancer, suggesting PDE6D as a metabolic-therapy modifier.\",\n      \"evidence\": \"Xenograft model with metabolomic/transcriptomic profiling and PDE6D inhibitor combination\",\n      \"pmids\": [\"40216151\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"Molecular link between PDE6D and cGMP/PKG not directly validated\", \"Omics-based inference without mechanistic dissection\", \"Causality versus correlation not established\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"A farnesylated tetra-peptide inhibitor blocked PDE6D cargo binding but only weakly affected K-Ras membrane anchorage and MAPK signaling, challenging PDE6D as a surrogate target for K-Ras inhibition.\",\n      \"evidence\": \"Genetically encoded inhibitor, knockdown comparison, membrane anchorage and MAPK assays (preprint)\",\n      \"pmids\": [\"bio_10.1101_2025.09.29.679187\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Preprint, not yet peer-reviewed\", \"Discrepancy with small-molecule inhibitor studies unresolved\", \"Context-dependence of K-Ras dependence on PDE6D unclear\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The structural and kinetic logic governing how distinct cargoes are differentially loaded, retained, and released by PDE6D across tissues, and whether PDE6D is a tractable target for K-Ras-driven cancers, remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No unified affinity/release model across cargoes\", \"Conflicting evidence on PDE6D as a K-Ras anticancer target\", \"Tissue-specific cargo dependencies not mapped\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0008289\", \"supporting_discovery_ids\": [0, 4, 5, 7, 10]},\n      {\"term_id\": \"GO:0140104\", \"supporting_discovery_ids\": [1, 2, 3, 7]},\n      {\"term_id\": \"GO:0140313\", \"supporting_discovery_ids\": [0, 7]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005929\", \"supporting_discovery_ids\": [1, 5, 10]},\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [0, 7]},\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [7, 9]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-9609507\", \"supporting_discovery_ids\": [1, 2, 3, 5, 10]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [7, 8, 9]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"KRAS\", \"INPP5E\", \"RPGR\", \"ARL3\", \"ARL13B\", \"GRK1\", \"PDE6\", \"ARL2\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"tie","faith_supported":7,"faith_total":7,"faith_pct":100.0}}