{"gene":"CDC37","run_date":"2026-06-09T22:57:18","timeline":{"discoveries":[{"year":1983,"finding":"CDC37 is an essential gene in Saccharomyces cerevisiae required for function at Start, the controlling event of the cell division cycle; the CDC37 locus was isolated, transcriptionally characterized, and mapped.","method":"Genetic complementation, plasmid library screening, R-loop analysis, Northern blotting","journal":"Molecular and cellular biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic isolation and transcriptional characterization in yeast, single lab, foundational but limited functional mechanistic detail","pmids":["6346060"],"is_preprint":false},{"year":1994,"finding":"Drosophila Cdc37 (E(sev)3B) is required for signaling by the Sevenless receptor tyrosine kinase; mutations in cdc37 dominantly enhance mutations in Dmcdc2, linking Cdc37 to both RTK signaling and cell cycle kinase regulation.","method":"Genetic screen, epistasis analysis, dominant enhancement of Dmcdc2 mutations","journal":"Cell","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic epistasis in Drosophila, ortholog confirmed, multiple kinase interactions demonstrated","pmids":["8020093"],"is_preprint":false},{"year":1995,"finding":"Yeast Cdc37 is required for association of the protein kinase Cdc28 with both G1 cyclins (Cln2) and mitotic cyclins (Clb2); loss of Cdc37 function causes decreased Cdc28 activity and reduced cyclin binding.","method":"Temperature-sensitive mutant analysis, co-immunoprecipitation, kinase activity assays","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic loss-of-function with biochemical readout (kinase activity, co-IP), yeast ortholog","pmids":["7753858"],"is_preprint":false},{"year":1995,"finding":"Vertebrate Cdc37 (first cloned) binds hyaluronan, chondroitin sulfate, and heparin in vitro via glycosaminoglycan-binding motifs, suggesting a role for glycosaminoglycans in cell division control.","method":"cDNA cloning, in vitro glycosaminoglycan binding assay, immunoscreening","journal":"The Journal of biological chemistry","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single lab, in vitro binding only, functional significance unestablished","pmids":["7608185"],"is_preprint":false},{"year":1996,"finding":"Mammalian p50Cdc37 is a protein kinase-targeting subunit of Hsp90 that binds and stabilizes Cdk4; Cdc37 is sufficient to target Hsp90 to Cdk4; the Cdc37/Hsp90 complex associates preferentially with Cdk4 not bound to D-type cyclins and promotes Cdk4 stability.","method":"Co-immunoprecipitation, insect cell coexpression, pharmacological Hsp90 inhibition (geldanamycin), half-life measurement","journal":"Genes & development","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal methods (co-IP, in vivo and in vitro reconstitution, pharmacological inhibition), replicated across labs","pmids":["8666233"],"is_preprint":false},{"year":1996,"finding":"Mammalian CDC37 physically interacts with CDK4 and CDK6 but not with Cdc2, Cdk2, Cdk3, Cdk5, or cyclins; Cdc37 does not directly activate or inhibit Cdk4/cyclin D1 kinase but facilitates complex assembly between Cdk4 and cyclin D1 in vitro; Cdc37 competes with p16 for binding to Cdk4.","method":"Yeast two-hybrid, co-immunoprecipitation, in vitro binding and kinase assays, competition assay","journal":"Oncogene","confidence":"High","confidence_rationale":"Tier 2 / Strong — yeast two-hybrid plus in vitro functional validation, multiple orthogonal methods","pmids":["9150368"],"is_preprint":false},{"year":1996,"finding":"CDC37 is required for p60v-src activity and its maintenance in a soluble, biologically active form in yeast; loss of Cdc37 function reduces v-Src-dependent tyrosine phosphorylation and shifts v-Src to urea-solubilized (insoluble) fractions.","method":"Temperature-sensitive cdc37 mutant analysis, Western blotting, fractionation, tyrosine phosphorylation assay","journal":"Molecular biology of the cell","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple cdc37 alleles, biochemical fractionation, functional kinase readout","pmids":["8885235"],"is_preprint":false},{"year":1997,"finding":"Cdc37 functions as an autonomous molecular chaperone: in vitro it maintains denatured beta-galactosidase in an activation-competent state and stabilizes mature but unstable casein kinase II; in vivo, Cdc37 overexpression compensates for decreased Hsp90 function specifically for v-Src kinase but not for the glucocorticoid receptor, demonstrating chaperone specificity.","method":"In vitro refolding assay, in vivo genetic complementation, kinase stability assays","journal":"Genes & development","confidence":"High","confidence_rationale":"Tier 1 / Strong — in vitro reconstitution plus in vivo genetic assays, multiple client proteins tested","pmids":["9242486"],"is_preprint":false},{"year":1997,"finding":"CDC37 is required for proper spindle pole body (SPB) duplication in yeast; CDC37 was identified as a multicopy suppressor of mps1-1; in cdc37-1 mutants, Mps1 kinase activity is markedly reduced despite normal Mps1 protein levels, indicating CDC37 is required for Mps1 kinase activity.","method":"Multicopy suppressor screen, genetic epistasis, kinase activity assay, electron microscopy","journal":"The Journal of cell biology","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic suppressor screen, biochemical kinase assay, structural phenotype by EM","pmids":["9060463"],"is_preprint":false},{"year":1997,"finding":"p50 (mammalian Cdc37) is the 50-kDa protein in Raf-1 and pp60(v-src) complexes; immunocytochemistry shows primarily cytoplasmic localization around the nuclear membrane.","method":"Protein purification, peptide sequencing, cDNA cloning, co-immunoprecipitation, immunocytochemistry","journal":"Biochemistry","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — protein identification confirmed by multiple methods (sequencing, cloning, co-IP, ICC), single lab","pmids":["9132011"],"is_preprint":false},{"year":1998,"finding":"p50(cdc37) binds directly to the catalytic domain of Raf (sufficient for interaction); p50(cdc37) binds to a site on Hsp90 topologically adjacent to but distinct from the TPR acceptor site; p50(cdc37) and TPR domain proteins form mutually exclusive complexes with Hsp90.","method":"Co-immunoprecipitation, direct binding assays, competition assays with TPR domain proteins","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 / Strong — direct binding mapping, mutual exclusivity assays, multiple orthogonal approaches","pmids":["9685350"],"is_preprint":false},{"year":1999,"finding":"p50(cdc37) is the primary determinant of Hsp90 recruitment to Raf-1; coexpression of p50(cdc37) with Raf-1 activates Raf-1 in Sf9 cells; a p50(cdc37) mutant unable to recruit Hsp90 inhibits Raf-1 and MAPK activation; formation of a ternary Raf-1–p50(cdc37)–Hsp90 complex is required for Raf-1 kinase activity.","method":"Baculovirus coexpression, dominant-negative mutant, geldanamycin treatment, kinase activity assay","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 2 / Strong — dominant-negative and pharmacological inhibition with multiple kinase readouts, Sf9 reconstitution","pmids":["10022854"],"is_preprint":false},{"year":1999,"finding":"Cdc37 is required for activity of the yeast kinase Ste11; Cdc37, Ste11, and Hsp90 co-precipitate pairwise; loss of Cdc37 impairs pheromone signaling and Ste11 accumulation/functional maturation, establishing Ste11 as the first endogenous Cdc37 client in yeast.","method":"Genetic cdc37 mutant analysis, co-immunoprecipitation, pheromone signaling assays","journal":"FEBS letters","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — co-IP plus functional genetic assay, single lab","pmids":["10664467"],"is_preprint":false},{"year":1999,"finding":"ZAP70 kinase domain mutant (M572L) is bound and restored by Cdc37 overexpression; this restoration requires functional HSP90; Cdc37 acts as a molecular chaperone for a temperature-sensitive kinase domain mutant of ZAP70.","method":"Mutant ZAP70 expression, Cdc37 overexpression rescue, co-immunoprecipitation, kinase activity assay","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — co-IP and functional rescue with defined mutant, single lab","pmids":["10574909"],"is_preprint":false},{"year":2000,"finding":"Cdc37 promotes stability of both Cdc28 and Cak1 kinases in yeast; pulse-chase analysis shows Cdc28 and Cak1 are destabilized when Cdc37 function is absent during (but not after) translation, indicating a cotranslational role in kinase folding.","method":"Temperature-sensitive mutant, pulse-chase analysis, co-expression in insect cells, kinase activity assay","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 2 / Strong — pulse-chase kinetics, insect cell coexpression, multiple kinase substrates, yeast ortholog","pmids":["10629030"],"is_preprint":false},{"year":2000,"finding":"p50(cdc37) is a nonexclusive Hsp90 cochaperone found in immunoadsorptions with multiple cochaperones (FKBP52, cyp40, p60HOP, Hsp70, p23); it participates in Hsp90-mediated folding of immature kinase molecules and responds to Hsp90's nucleotide-regulated conformational switching.","method":"Co-immunoprecipitation with multiple antibodies, salt-stability assay, geldanamycin treatment","journal":"Biochemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple co-IP approaches, nucleotide-state dependency shown, single lab","pmids":["10858314"],"is_preprint":false},{"year":2000,"finding":"Cdc37 functionally interacts with human androgen receptor (AR) via its ligand-binding domain but not with glucocorticoid receptor; dominant-negative Cdc37 downregulates full-length AR; Cdc37 has broader polypeptide client specificity than kinases alone.","method":"Reticulocyte lysate binding assay, yeast model, dominant-negative overexpression, immunoprecipitation","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple orthogonal assays (reticulocyte, yeast, mammalian cells), single lab","pmids":["11085988"],"is_preprint":false},{"year":2001,"finding":"p50(cdc37) interacts co-translationally with nascent HRI kinase chains; the N-terminal domain of p50(cdc37) binds immature HRI while the C-terminal region binds Hsp90; p50(cdc37) stimulates HRI activation in response to heme deficiency; geldanamycin disrupts both Hsp90 and p50(cdc37) binding to HRI, indicating that Hsp90's nucleotide conformation regulates p50(cdc37)'s kinase-binding activity.","method":"Reticulocyte lysate translation, co-immunoprecipitation, domain mapping with truncation mutants, geldanamycin treatment, kinase activity assay","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 / Strong — co-translational interaction defined, domain mapping, functional kinase assay, nucleotide-state dependency","pmids":["11036079"],"is_preprint":false},{"year":2001,"finding":"Cdc37 co-immunoprecipitates with MOK kinase along with Hsp90, Hsc70, Hsp70, and Hsp60 but not GRP94, FKBP52, or Hop; kinase catalytic subdomains I-IV are required for Hsp90 binding.","method":"Co-immunoprecipitation, deletion mutant mapping, geldanamycin-induced degradation assay","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — co-IP with domain mapping, multiple related kinases tested, single lab","pmids":["11278794"],"is_preprint":false},{"year":2002,"finding":"Cdc37 (p50/CDC37) is a novel interaction partner of the duck hepatitis B virus reverse transcriptase (RT); p50 binds the RT independently of Hsp90 (demonstrated with p50deltaC mutant); this interaction is required for reverse transcription initiation in vitro and for viral DNA replication and RNA packaging in transfected cells.","method":"Co-immunoprecipitation, pull-down assay (in vitro and in vivo), purified protein direct interaction, functional reverse transcription assay, viral replication assay","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Moderate — purified protein direct binding, in vitro functional assay, cell-based replication assay, Hsp90-independent activity demonstrated","pmids":["11986322"],"is_preprint":false},{"year":2002,"finding":"Intracellular Akt forms a complex with Hsp90 and Cdc37; Hsp90 inhibition causes ubiquitination and proteasomal degradation of Akt, shortening its half-life from 36 to 12 h; Akt and PDK1 are the only PKA/PKB/PKC-family members affected by Hsp90 inhibitors.","method":"Co-immunoprecipitation, Hsp90 inhibitor (geldanamycin) treatment, pulse-chase half-life measurement, ubiquitination assay, proteasome inhibitor","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 / Strong — co-IP, pulse-chase kinetics, proteasome pathway defined, multiple orthogonal methods","pmids":["12176997"],"is_preprint":false},{"year":2002,"finding":"Cdc37 and Hsp90 are components of the ~900 kDa IKK complex; Cdc37 directly binds Hsp90 and directly binds the kinase domain of IKKα/IKKβ; geldanamycin disrupts this heterocomplex, preventing TNF-induced IKK activation, NF-κB activation, and IKK recruitment to TNF-R1.","method":"Co-immunoprecipitation, direct binding assay, gel filtration, geldanamycin treatment, NF-κB reporter assay, membrane recruitment assay","journal":"Molecular cell","confidence":"High","confidence_rationale":"Tier 2 / Strong — direct interaction mapping, multiple functional readouts, complex stoichiometry defined","pmids":["11864612"],"is_preprint":false},{"year":2002,"finding":"Cdc37p/p50(cdc37) suppresses Hsp90 ATPase activity (like Sti1/Hop/p60); Cdc37p binds Hsp90 as a dimer; suppressed ATPase is restored by immunophilin cochaperone Cpr6/Cyp40; unlike Sti1, Cdc37p forms a stable complex with geldanamycin-bound Hsp90.","method":"ATPase activity assay, analytical ultracentrifugation, geldanamycin displacement assay","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Strong — in vitro ATPase assay with defined mechanistic outcome, dimerization established, replicated across labs","pmids":["11916974"],"is_preprint":false},{"year":2002,"finding":"In yeast, CDC37 is a multicopy suppressor of CKII (cka2-13ts); Cdc37 is a physiological substrate of CKII, phosphorylated at Ser-14 and/or Ser-17; cdc37-S14,17A strains show severe growth defects and reduced CKII activity, and CKII activity is elevated at cell cycle phases requiring Cdc37; this defines a positive feedback loop between CKII and Cdc37.","method":"Multicopy suppressor screen, metabolic labeling + immunoprecipitation, site-directed mutagenesis (S14A, S17A, S14,17E), CKII kinase activity assay","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic suppressor, site-specific phosphomutants, kinase activity assay, multiple alleles","pmids":["12435747"],"is_preprint":false},{"year":2002,"finding":"Cdc37 is essential for chromosome segregation and cytokinesis in Drosophila; Cdc37 loss-of-function phenotypes closely resemble Aurora B inactivation; Aurora B interacts with and requires the Cdc37/Hsp90 complex for stability.","method":"Drosophila genetics (loss-of-function), epistasis, co-immunoprecipitation, mitosis/meiosis phenotype analysis","journal":"The EMBO journal","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic epistasis in metazoan model, co-IP, Aurora B identified as Cdc37/Hsp90 client","pmids":["12374737"],"is_preprint":false},{"year":2002,"finding":"The protein kinase-binding domain of Cdc37 alone is sufficient for yeast cell viability, for efficient MAP kinase pathway signaling, and for partial v-Src folding independent of Hsp90; CDC37 overexpression suppresses Sti1 deletion defects in v-Src folding.","method":"CDC37 truncation mutants, yeast viability assay, MAP kinase signaling reporter, v-Src folding assay","journal":"The Journal of cell biology","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple truncation mutants, cell viability and biochemical assays, Hsp90-independent activity demonstrated","pmids":["12499358"],"is_preprint":false},{"year":2003,"finding":"Hsp90 and Cdc37 interact with the kinase domain of LKB1 and regulate LKB1 stability; Hsp90 inhibitors (geldanamycin, novobiocin) cause proteasomal ubiquitination and degradation of LKB1; a sporadic testicular cancer point mutation in LKB1 weakens interaction with both Hsp90 and Cdc37.","method":"LKB1 purification, co-immunoprecipitation, Hsp90 inhibitor treatment, ubiquitination assay, cancer mutation analysis","journal":"The Biochemical journal","confidence":"High","confidence_rationale":"Tier 2 / Strong — purification, direct co-IP, pharmacological inhibition, mutational analysis, proteasomal pathway defined","pmids":["12489981"],"is_preprint":false},{"year":2003,"finding":"Cdc37 is a positive regulator of Spc1 SAPK in fission yeast; Cdc37 physically interacts with Spc1; cdc37 mutation reduces Spc1 protein levels and stress-induced Spc1 phosphorylation by Wis1 MAPKK; Hsp90 mutation does not affect Spc1, indicating a Hsp90-independent function of Cdc37 for this client.","method":"Genetic screen, co-immunoprecipitation, kinase assay, stress signaling reporter assay","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic screen, co-IP, phosphorylation assay, Hsp90-independent result validated","pmids":["12861001"],"is_preprint":false},{"year":2004,"finding":"Crystal structure of the Hsp90 N-domain/Cdc37 core complex reveals that dimeric p50(cdc37) binds surfaces of the Hsp90 N-domain implicated in ATP-dependent N-terminal dimerization; Cdc37 inserts an arginine side chain into the ATP binding pocket to disable catalysis and fixes the lid in an open conformation, arresting the Hsp90 ATPase cycle during client-protein loading.","method":"X-ray crystallography, ATPase activity assay, mutagenesis","journal":"Cell","confidence":"High","confidence_rationale":"Tier 1 / Strong — crystal structure plus biochemical validation, mechanism of ATPase inhibition defined at atomic level","pmids":["14718169"],"is_preprint":false},{"year":2004,"finding":"Mammalian CK2 phosphorylates Cdc37 at Ser13 in vitro and in vivo; Ser13 is the unique in vivo phosphorylation site; CK2 phosphorylation of Ser13 is essential for Cdc37's optimal binding to multiple kinase clients (Raf1, Akt, Aurora-B, Cdk4, Src, MOK, MAK, MRK) and for recruitment of Hsp90 to kinase-Cdc37 complexes.","method":"In vitro kinase assay with purified CK2, site-directed mutagenesis, in vivo phosphorylation (metabolic labeling), co-immunoprecipitation, CK2 inhibitor treatment","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 1 / Strong — in vitro kinase assay, unique phosphorylation site confirmed in vivo, multiple kinase clients tested, CK2 inhibitor validation","pmids":["15082798"],"is_preprint":false},{"year":2004,"finding":"Cdc37 comprises three discrete structural domains by limited proteolysis: N-terminal domain (residues 1-126) binds client kinases; middle domain (residues 128-282) binds Hsp90; C-terminal domain (283-378) has no ascribed function; residues S127-G163 serve as an interdomain switch; W7A and scanning alanine mutagenesis identified N-terminal residues critical for high-affinity kinase binding.","method":"Limited proteolysis, MALDI-TOF MS, peptide microsequencing, domain truncation, scanning alanine mutagenesis, functional binding assay","journal":"Biochemistry","confidence":"High","confidence_rationale":"Tier 1 / Strong — proteolysis + MS domain mapping, mutagenesis with functional validation","pmids":["14580204"],"is_preprint":false},{"year":2004,"finding":"Cdc37 recognizes alpha-C-helix and beta4-beta5 strands of the kinase N-lobe as primary binding determinants; Hsp90 requires interaction with adjacent subdomain structures spanning both N- and C-lobes to form high-affinity complexes; Cdc37 interacts only with the N-lobe of kinase catalytic domains.","method":"Crystal structure-guided kinase construct design, pull-down assay, salt-stability binding assay, molybdate-independent binding assay","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Moderate — structure-guided mutagenesis, in vitro binding assay with defined lobe constructs, single lab","pmids":["15258137"],"is_preprint":false},{"year":2004,"finding":"Cdc37 and Sti1 physically interact directly (without Hsp90); the combination of cdc37 and sti1 mutations is synthetically lethal in yeast; Cdc37 overexpression suppresses sti1 deletion and restores stable Hsp90 binding to Ste11.","method":"GST pull-down with purified proteins, co-immunoprecipitation, synthetic lethality screen, genetic suppression","journal":"Molecular biology of the cell / Biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct protein-protein interaction, genetic epistasis, single lab","pmids":["14742721","12437126"],"is_preprint":false},{"year":2004,"finding":"SAXS solution structure of human Hsp90β-Cdc37 complex shows that a Cdc37 dimer binds the two N-terminal domain/linker regions of the Hsp90 dimer, fixing them in a single conformation suitable for client protein recognition.","method":"Small angle X-ray scattering (SAXS), biochemical characterization","journal":"Journal of molecular biology","confidence":"Medium","confidence_rationale":"Tier 1 / Moderate — SAXS structural data, single lab, limited functional validation","pmids":["15223329"],"is_preprint":false},{"year":2005,"finding":"JAK1 (but not JAK2) interacts with Hsp90 and CDC37; both interactions are destabilized by Hsp90 inhibitors; CDC37 and Hsp90 are required for interferon type I and II signaling through stabilization of JAK1.","method":"Co-immunoprecipitation, siRNA knockdown, Hsp90 inhibitor treatment, interferon signaling assay (STAT1 phosphorylation, antiviral response)","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — co-IP, siRNA, and pharmacological evidence, single lab","pmids":["16280321"],"is_preprint":false},{"year":2006,"finding":"Single-particle electron microscopy of the Hsp90-Cdc37-Cdk4 ternary complex defines its 3D structure and stoichiometry; comparison with Hsp90 crystal structure localizes Cdc37 and Cdk4 positions and suggests conformational changes in kinase coupled to Hsp90 ATPase cycle.","method":"Complex purification, stoichiometry determination, single-particle electron microscopy, crystal structure comparison","journal":"Molecular cell","confidence":"High","confidence_rationale":"Tier 1 / Strong — EM structure of full ternary complex, stoichiometry defined, structural mechanistic model","pmids":["16949366"],"is_preprint":false},{"year":2006,"finding":"Cdc37 interacts with the glycine-rich loop (GXFG motif in canonical GXGXXG) of protein kinase N-lobes; the GSGSFG motif of Raf-1 is necessary for Cdc37 association; the C-terminal portions of kinases determine differential affinity for Cdc37; an unphosphorylated activation segment threonine in non-client kinases permits transient Cdc37 interaction.","method":"Phage display, LC-MS/MS, deletion and chimeric kinase mutants, co-immunoprecipitation","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 2 / Strong — phage display identifies motif, confirmed by mutagenesis and co-IP, multiple kinases tested","pmids":["16611982"],"is_preprint":false},{"year":2006,"finding":"In C. elegans embryos, CDC-37 (Cdc37 homolog) is required for establishment phase of embryonic polarity; CDC-37 reduction allows PAR-3-independent cortical accumulation of PAR-6 and PKC-3; CDC-37 acts by maintaining PKC-3 levels and influencing other client proteins; two sites for PAR-6 cortical association are revealed.","method":"RNAi knockdown (cdc-37), live imaging, immunofluorescence, epistasis with par mutants","journal":"Development (Cambridge, England)","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — RNAi loss-of-function with specific polarity phenotype, epistasis analysis, C. elegans ortholog","pmids":["16943281"],"is_preprint":false},{"year":2007,"finding":"Cdc37 is required for Ste11-mediated pheromone signaling in yeast; Cdc37 matures de novo synthesized IKKs into enzymatically competent kinases; Cdc37 recruits Hsp90 to the IKK complex transiently and preferentially via IKKα; Cdc37 binding is conferred by both N-terminal and C-terminal residues.","method":"RNAi knockdown, IKK kinase maturation assay, co-immunoprecipitation, domain mapping","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — RNAi and domain mapping, functional kinase maturation assay, single lab","pmids":["17728246"],"is_preprint":false},{"year":2007,"finding":"Cdc37 is required for stability of ~50% of the yeast kinome (51/65 kinases tested); pulse-labeling shows Cdc37 protects nascent kinase chains from rapid cotranslational degradation; kinase abundance can be restored at reduced temperature without fully restoring activity.","method":"Large-scale kinase abundance measurement in cdc37 mutant yeast, pulse-chase labeling, temperature-shift experiments","journal":"The Journal of cell biology","confidence":"High","confidence_rationale":"Tier 2 / Strong — genome-scale analysis with pulse-chase validation, demonstrates general cotranslational chaperone role","pmids":["17242065"],"is_preprint":false},{"year":2007,"finding":"Pink1 kinase is a novel Cdc37/Hsp90 client kinase; the Cdc37/Hsp90 chaperone system influences both the subcellular distribution and the 66/55 kDa protein ratio of Pink1; PD-causing Pink1 mutations decrease while Parkin expression increases the Pink1 66/55 kDa ratio.","method":"Mass spectrometry of immunoisolated Pink1 complexes, co-immunoprecipitation, Hsp90 inhibitor treatment, subcellular fractionation","journal":"Human molecular genetics","confidence":"High","confidence_rationale":"Tier 2 / Strong — unbiased MS identification, co-IP confirmation, functional consequences of chaperone disruption shown","pmids":["18003639"],"is_preprint":false},{"year":2007,"finding":"Aurora B kinase requires Cdc37/Hsp90 complex for stability (confirmed in Drosophila); MLK3 associates with Hsp90 and p50(cdc37) through its catalytic domain; geldanamycin reduces MLK3 levels and blocks TNF-α-induced MLK3 and JNK activation.","method":"Co-immunoprecipitation, affinity purification with LC-MS/MS identification, geldanamycin treatment, kinase activity assay","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — affinity purification + MS + co-IP, functional kinase readout, single lab","pmids":["15001580"],"is_preprint":false},{"year":2008,"finding":"Cdc37 Ser13 phosphorylation is constitutive in uncomplexed Cdc37, in binary kinase-Cdc37 complex, and in ternary Hsp90-Cdc37-kinase complex; PP5/Ppt1 phosphatase specifically dephosphorylates pSer13-Cdc37 when in the ternary Hsp90 complex but not isolated Cdc37; this targeted dephosphorylation directly regulates activation of kinase clients by Hsp90-Cdc37.","method":"Phosphospecific antibodies, in vitro phosphatase assay, yeast and human tumor cell co-immunoprecipitation, PP5/Ppt1 genetic knockdown, kinase client activation assay","journal":"Molecular cell","confidence":"High","confidence_rationale":"Tier 1 / Strong — in vitro phosphatase assay, validated in two organisms, complex-specific dephosphorylation mechanism defined","pmids":["18922470"],"is_preprint":false},{"year":2008,"finding":"Conventional and novel (but not atypical) PKC isozymes bind Cdc37 and Hsp90 through a conserved PXXP motif in the C-terminal tail; mutation of both Pro-616 and Pro-619 abolishes PKC phosphorylation and activity; Hsp90 and Cdc37 inhibitors reduce the rate of PKC processing phosphorylation; Hsp90 binding regions on PKC are identified around the PXXP segment via peptide array overlay.","method":"Co-immunoprecipitation, site-directed mutagenesis (PXXP and Tyr-446 to Ala), Hsp90/Cdc37 inhibitor treatment, peptide array overlay, processing phosphorylation assay","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Strong — mutagenesis defining binding motif, peptide array, functional phosphorylation assay, multiple PKC isozymes","pmids":["19091746"],"is_preprint":false},{"year":2008,"finding":"Celastrol disrupts Hsp90-Cdc37 interaction by binding to the Hsp90 C-terminal domain (not the ATP pocket), protecting it from trypsin digestion; Cdc37 binds ADP-bound/nucleotide-free Hsp90 but not ATP-bound Hsp90; classical Hsp90 inhibitors (geldanamycin) do not disrupt Hsp90-Cdc37 interaction.","method":"GST pull-down, ELISA, proteolytic fingerprinting, celastrol binding assay, ATPase assay","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Strong — in vitro reconstitution, multiple biochemical methods, Cdc37 nucleotide-state preference mapped","pmids":["19858214"],"is_preprint":false},{"year":2010,"finding":"Hsp90-Cdc37 complex is part of the p38α signaling complex; Cdc37 directly binds p38α; Cdc37 expression is sufficient and necessary to suppress noncanonical p38α autophosphorylation but has no impact on canonical MKK3-mediated p38 activation.","method":"Proteomics + biochemical co-immunoprecipitation, Cdc37 knockdown/overexpression, p38 activation assay (autophosphorylation vs canonical), cardiomyocyte system","journal":"Circulation research","confidence":"High","confidence_rationale":"Tier 2 / Strong — proteomic discovery confirmed by co-IP, gain- and loss-of-function with specific mechanistic discrimination","pmids":["20299663"],"is_preprint":false},{"year":2011,"finding":"Hsp90-Cdc37 complex stabilizes and activates Ulk1 kinase; Ulk1-Hsp90-Cdc37 interaction is required for phosphorylation and release of Atg13 from Ulk1 and for Atg13 recruitment to damaged mitochondria; Hsp90-Cdc37, Ulk1, and Atg13 phosphorylation are all required for efficient mitophagy.","method":"Co-immunoprecipitation, Hsp90 inhibitor treatment, Cdc37 knockdown, mitophagy assay, phosphorylation analysis","journal":"Molecular cell","confidence":"High","confidence_rationale":"Tier 2 / Strong — pathway defined by co-IP, pharmacological and genetic loss-of-function, specific mitophagy readout","pmids":["21855797"],"is_preprint":false},{"year":2011,"finding":"Cdc37 co-localizes with tau in neuronal cells and physically interacts with tau from human brain; Cdc37 suppression destabilizes tau and alters its phosphorylation profile by reducing levels of specific tau kinases (Cdk5, Akt) without affecting others (GSK3β, Mark2); Cdc37 overexpression prevents tau clearance following Hsp90 inhibition.","method":"Co-immunoprecipitation from human brain, immunofluorescence colocalization, Cdc37 siRNA knockdown/overexpression, tau kinase level and phosphorylation analysis","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct interaction from human brain tissue, functional consequences with gain and loss of function, single lab","pmids":["21367866"],"is_preprint":false},{"year":2011,"finding":"Cdc37 directly interacts with IRE1α through a conserved cytosolic motif; Cdc37 knockdown or disruption of Cdc37-IRE1α interaction increases basal IRE1α kinase activity; Cdc37-mediated Hsp90/Cdc37 interaction with IRE1α maintains basal IRE1α activity and contributes to normal insulin synthesis and secretion.","method":"Co-immunoprecipitation, Cdc37 siRNA knockdown, IRE1α activity assay, insulin synthesis/secretion measurement","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — co-IP, siRNA, functional IRE1α activity assay, single lab","pmids":["22199355"],"is_preprint":false},{"year":2012,"finding":"Cdc37 disruption triggers autophagic clearance of TDP-43; Cdc37 depletion causes proteolytic cleavage and nuclear retrotranslocation of TDP-43 followed by autophagic uptake; tau accumulation prevents clearance of cleaved TDP-43.","method":"Cdc37 siRNA knockdown, Hsp90 inhibitor treatment, TDP-43 localization assay, autophagy pathway analysis (beclin1 knockdown)","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — siRNA and pharmacological with defined pathway, multiple mechanistic steps defined, single lab","pmids":["22674575"],"is_preprint":false},{"year":2012,"finding":"Tyrosine phosphorylation of p50(Cdc37) at Y4 and Y298 disrupts client-p50(Cdc37) association; Hsp90 phosphorylation at Y197 dissociates p50(Cdc37) from Hsp90; these phosphorylation events provide directionality to the chaperone cycle; subsequent Hsp90 Y313 phosphorylation promotes AHA1 recruitment.","method":"Site-directed mutagenesis of phosphotyrosine sites, co-immunoprecipitation, in vitro phosphorylation, ATPase assay","journal":"Molecular cell","confidence":"High","confidence_rationale":"Tier 1 / Strong — mutagenesis of specific tyrosines, mechanistic ordering of chaperone cycle events, multiple orthogonal methods","pmids":["22727666"],"is_preprint":false},{"year":2013,"finding":"Cdc37 directly antagonizes ATP binding to client kinases; ATP-competitive kinase inhibitors (vemurafenib, lapatinib) block Cdc37 binding to client kinases such as B-Raf and ErbB2, depriving them of access to the Hsp90-Cdc37 complex and causing their degradation in cancer cells.","method":"In vitro ATP binding assay, co-immunoprecipitation, kinase inhibitor treatment, client kinase degradation assay","journal":"Nature chemical biology","confidence":"High","confidence_rationale":"Tier 1 / Strong — in vitro ATP binding antagonism demonstrated, mechanistic link to kinase degradation in cells established","pmids":["23502424"],"is_preprint":false},{"year":2013,"finding":"ERK5 interacts with Hsp90-Cdc37 in resting cells; activation of ERK5 induces Hsp90 dissociation from the ERK5-Cdc37 complex via ERK5 C-tail autophosphorylation, leading to nuclear translocation; Cdc37 overexpression alone induces Hsp90 dissociation and nuclear translocation of kinase-inactive ERK5, demonstrating Cdc37-driven kinase-independent transcriptional activity.","method":"Tandem affinity purification, co-immunoprecipitation, Hsp90/Cdc37 inhibition, nuclear translocation assay, transcriptional reporter","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 2 / Strong — TAP identification, co-IP, gain/loss-of-function, novel kinase-independent Cdc37 mechanism defined","pmids":["23428871"],"is_preprint":false},{"year":2015,"finding":"RIP3 kinase activation during necroptosis requires a physical association with the HSP90-CDC37 cochaperone complex; CDC37 knockdown prevents cells from responding to necroptosis stimuli; HSP90 inhibitors block RIP3 activation and prevent systemic inflammatory response syndrome in TNF-α-treated rats.","method":"Co-immunoprecipitation, CDC37 siRNA knockdown, HSP90 inhibitor treatment, necroptosis assay, in vivo rat SIRS model","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 2 / Strong — co-IP, genetic knockdown, pharmacological inhibition, in vivo validation","pmids":["25852146"],"is_preprint":false},{"year":2016,"finding":"Cryo-EM structure of the Hsp90-Cdc37-Cdk4 complex at 3.9 Å reveals that the two lobes of Cdk4 are completely separated with the β4-β5 sheet unfolded; Cdc37 mimics part of the kinase N-lobe, stabilizing an open kinase conformation by wedging between the two lobes; Hsp90 clamps around the unfolded kinase β5 strand, protecting it in a trapped unfolded state.","method":"Cryo-electron microscopy (3.9 Å), complex reconstitution","journal":"Science (New York, N.Y.)","confidence":"High","confidence_rationale":"Tier 1 / Strong — near-atomic resolution cryo-EM structure, first full-length complex structure, mechanistic model validated by extensive prior biochemical data","pmids":["27339980"],"is_preprint":false},{"year":2016,"finding":"Cdc37 acts as a general kinase scanning factor that participates in selective client recruitment by challenging the conformational stability of client kinases through local unfolding; stable complex formation requires multidomain cochaperone interface and is accompanied by conformational changes in clients but not nonclients; this metastable conformational state is the basis for Hsp90-dependence.","method":"NMR, hydrogen-deuterium exchange, in vitro binding and stability assays, client vs nonclient kinase discrimination assay","journal":"Molecular cell","confidence":"High","confidence_rationale":"Tier 1 / Strong — NMR and HDX with functional binding assays, mechanistic model for client sorting defined","pmids":["27105117"],"is_preprint":false},{"year":2017,"finding":"Assembly of CDK4 and CDK6 into protein complexes is differentially regulated by Cdc37-Hsp90; Cdc37-Hsp90 relinquishes CDK6 to D3- and virus-type cyclins and INK inhibitors, whereas CDK4 is less readily relinquished to cyclins; CIP/KIP CDK inhibitors cooperate with D-type cyclins to form Cdc37-resistant ternary CDK4/6-cyclin complexes.","method":"Co-immunoprecipitation, competition binding assay, differential release assay for CDK4 vs CDK6","journal":"Cell reports","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal binding assays, differential CDK4/CDK6 regulation established, mechanistic model for assembly factor activity","pmids":["29091774"],"is_preprint":false},{"year":2008,"finding":"Crystal structure of the 16-kDa middle domain of human Cdc37 at 1.88 Å shows it exists as a monomer; NMR and mutagenesis identify Leu-205 as a key residue for Cdc37-Hsp90 N-domain complex formation.","method":"X-ray crystallography (1.88 Å), NMR spectroscopy, site-directed mutagenesis (L205)","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Strong — crystal structure plus NMR and mutagenesis, key residue identified","pmids":["19073599"],"is_preprint":false},{"year":2022,"finding":"CryoEM structure of the full-length RAF1-HSP90-CDC37 complex reveals that RAF1 kinase N-lobe is unfolded with its hydrophobic core trapped in the HSP90 dimer; CDC37 wraps around HSP90 and interacts with both N- and C-lobes of RAF1; the structure indicates how CDC37 discriminates between different RAF family members; disruption of CDC37-DFG segment interaction reveals pharmacological vulnerabilities for RAF1 degradation.","method":"Cryo-electron microscopy (full-length complex), structural analysis","journal":"Molecular cell","confidence":"High","confidence_rationale":"Tier 1 / Strong — near-atomic cryo-EM of full-length ternary complex, mechanistic basis for RAF1 regulation and CDC37 selectivity revealed","pmids":["36055235"],"is_preprint":false},{"year":2022,"finding":"CryoEM structures of the HSP90-CDC37-BRAFV600E-PP5 complex in autoinhibited and activated conformations reveal that PP5 is activated by recruitment to HSP90 complexes; the V600E mutation favors BRAF association with HSP90-CDC37; PP5 comprehensively dephosphorylates client proteins including BRAFV600E and CRAF, removing 14-3-3 interaction sites and performing a 'factory reset' prior to kinase release.","method":"CryoEM structure determination, proteomic phosphatase activity analysis, co-immunoprecipitation","journal":"Nature communications","confidence":"High","confidence_rationale":"Tier 1 / Strong — multiple cryo-EM structures of different complex states, proteomic phosphatase activity validation, mechanism for kinase release defined","pmids":["36446791"],"is_preprint":false},{"year":2012,"finding":"Cdc37 is present on the cell surface of breast cancer cells where it interacts with surface HSP90, HER2, and EGFR; functional inhibition of surface HSP90 disrupts the Cdc37/HSP90 and Cdc37/ErbB receptor complexes on the cell surface.","method":"Cell-impermeable anti-Cdc37 antibody, co-immunoprecipitation, cancer cell motility assay","journal":"PloS one","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — cell surface localization demonstrated with impermeable antibody, co-IP of surface complexes, single lab","pmids":["22912728"],"is_preprint":false},{"year":2013,"finding":"CDC37 mutants with single/double point mutations at M164 and L205 (greatly reduced HSP90 binding) retain client kinase association and phenocopy wild-type CDC37 in increasing CDK4-HSP90 association and CDK4 levels; CDC37 can stabilize kinase clients through a mechanism not requiring its direct interaction with HSP90, but still requiring HSP90 activity.","method":"Site-directed mutagenesis (M164A, L205A, double mutant), co-immunoprecipitation, client kinase level and half-life measurement, siRNA rescue experiment","journal":"Oncogene","confidence":"High","confidence_rationale":"Tier 2 / Strong — mutagenesis with comprehensive functional validation, HSP90-binding-independent mechanism defined, multiple orthogonal assays","pmids":["24292678"],"is_preprint":false}],"current_model":"CDC37 (p50Cdc37) is a kinase-specific cochaperone of HSP90 that acts as a two-component scaffold: its N-terminal domain directly recognizes and locally unfolds client kinase N-lobes (via the α-C-helix/β4-β5/glycine-rich loop), while its middle domain binds HSP90's N-terminal nucleotide-binding domain, inserting an arginine into the ATP pocket to arrest the HSP90 ATPase cycle during client loading; cryo-EM structures of the Hsp90-Cdc37-Cdk4 and Hsp90-CDC37-RAF1 complexes show the kinase N-lobe is completely unfolded and trapped by HSP90, with CDC37 wedging between the lobes to stabilize this open state; CDC37 Ser13 must be phosphorylated by CK2 for efficient kinase binding, and this phosphorylation is removed by PP5 (recruited to HSP90 complexes) to trigger client release after a 'factory reset' dephosphorylation; tyrosine phosphorylation of CDC37 at Y4/Y298 and of HSP90 at Y197 further regulate client and CDC37 release during cycle progression; ATP-competitive kinase inhibitors directly compete with CDC37 for kinase binding, explaining their ability to deprive oncogenic kinases of chaperone support; beyond kinases, CDC37 also chaperones the hepadnavirus reverse transcriptase and directly stabilizes tau, and it has Hsp90-independent chaperone activity; loss of CDC37 function leads to proteasomal or autophagic degradation of client kinases cotranslationally."},"narrative":{"mechanistic_narrative":"CDC37 (p50Cdc37) is a kinase-specific cochaperone of HSP90 that selectively recruits, folds, and stabilizes a large fraction of the cellular protein kinome, originally defined as an essential cell-cycle gene acting at Start in yeast and as a regulator of receptor-tyrosine-kinase signaling and cell-cycle kinases in metazoa [PMID:6346060, PMID:8020093, PMID:7753858]. It functions as a two-component scaffold: an N-terminal domain (residues 1–126) recognizes client kinases by engaging the αC-helix/β4-β5 strands and the glycine-rich GXFG loop of the kinase N-lobe, while a middle domain (128–282) docks onto the HSP90 N-terminal domain [PMID:14580204, PMID:15258137, PMID:16611982]. Mechanistically, CDC37 binds the HSP90 N-domain surface required for ATP-dependent dimerization and inserts an arginine into the ATP pocket to arrest the HSP90 ATPase cycle during client loading [PMID:14718169]. Cryo-EM of the HSP90–CDC37–CDK4 and full-length HSP90–CDC37–RAF1 complexes shows the client kinase N-lobe completely unfolded and trapped within the HSP90 dimer, with CDC37 mimicking part of the N-lobe and wedging between the kinase lobes to stabilize this open state [PMID:27339980, PMID:36055235]; CDC37 acts as a general kinase \"scanning factor\" that discriminates clients from non-clients by challenging their conformational stability through local unfolding [PMID:27105117]. The cycle is regulated by phosphorylation: CK2 phosphorylation of CDC37 at Ser13 is required for efficient kinase-client binding and HSP90 recruitment [PMID:15082798], complex-specific dephosphorylation of pSer13 by PP5/Ppt1 triggers client activation and release in a \"factory reset\" mechanism [PMID:18922470, PMID:36446791], and tyrosine phosphorylation of CDC37 (Y4/Y298) and HSP90 (Y197) provides directionality by dissociating client and CDC37 from the chaperone machine [PMID:22727666]. Through this activity CDC37 stabilizes a broad client set spanning CDK4/CDK6, Raf-1/B-Raf, v-Src, Akt, IKK, JAK1, Aurora B, ULK1, RIP3 and many others, governing cell-cycle progression, MAPK and NF-κB signaling, mitophagy and necroptosis [PMID:8666233, PMID:10022854, PMID:12176997, PMID:11864612, PMID:12374737, PMID:21855797, PMID:25852146]. CDC37 also retains HSP90-independent chaperone activity, directly binding and maturing certain kinases and non-kinase clients such as the hepadnavirus reverse transcriptase and tau [PMID:9242486, PMID:11986322, PMID:12499358, PMID:21367866]. Loss of CDC37 function leads to cotranslational proteasomal or autophagic degradation of nascent client kinases [PMID:17242065, PMID:10629030]. Because ATP-competitive kinase inhibitors directly compete with CDC37 for the kinase N-lobe, they deprive oncogenic kinases of chaperone support and promote their degradation [PMID:23502424].","teleology":[{"year":1983,"claim":"Established CDC37 as an essential gene controlling a discrete cell-cycle decision point, framing the question of which molecular activity underlies this requirement.","evidence":"Genetic complementation and transcriptional mapping in S. cerevisiae","pmids":["6346060"],"confidence":"Medium","gaps":["No molecular function assigned","No protein partners identified","Connection to kinases not yet made"]},{"year":1994,"claim":"Linked Cdc37 to both receptor-tyrosine-kinase signaling and cell-cycle kinase regulation, hinting that kinases are the common denominator of its function.","evidence":"Genetic screen and dominant enhancement of Dmcdc2 mutations in Drosophila","pmids":["8020093"],"confidence":"High","gaps":["Mechanism of kinase regulation unknown","Direct binding not demonstrated","HSP90 link not yet established"]},{"year":1996,"claim":"Identified CDC37 as a kinase-targeting subunit of HSP90 and defined CDK4 and v-Src as clients, recasting the gene as a kinase-specific HSP90 cochaperone.","evidence":"Co-IP, insect-cell coexpression, geldanamycin inhibition, half-life and fractionation assays (yeast and mammalian)","pmids":["8666233","9150368","8885235"],"confidence":"High","gaps":["Domain architecture undefined","Structural basis of HSP90 binding unknown","Whether activity is HSP90-dependent or autonomous unresolved"]},{"year":1997,"claim":"Demonstrated that CDC37 has autonomous chaperone activity and client specificity distinct from HSP90, and extended its role to spindle pole body duplication via Mps1.","evidence":"In vitro refolding assays, genetic complementation, multicopy suppressor screen and kinase activity assays","pmids":["9242486","9060463","9132011"],"confidence":"High","gaps":["Structural basis of autonomous chaperone activity unknown","How client specificity is encoded unresolved"]},{"year":1999,"claim":"Showed CDC37 is the primary determinant of HSP90 recruitment to clients (Raf-1, Ste11, ZAP70), establishing a defined ternary-complex requirement for kinase activity.","evidence":"Baculovirus coexpression, dominant-negative mutants, geldanamycin, co-IP and signaling assays","pmids":["10022854","10664467","10574909"],"confidence":"High","gaps":["Order of complex assembly unclear","Structural geometry of ternary complex unknown"]},{"year":2001,"claim":"Defined a two-domain architecture in which the CDC37 N-terminus binds nascent kinases cotranslationally while the C-terminal region binds HSP90, and showed HSP90 nucleotide state gates CDC37's kinase-binding activity.","evidence":"Reticulocyte-lysate translation, truncation domain mapping, geldanamycin, kinase activity assay (HRI)","pmids":["11036079"],"confidence":"High","gaps":["Precise domain boundaries not yet mapped","Atomic structure of either interface absent"]},{"year":2002,"claim":"Established the biochemical mechanism of HSP90 regulation (ATPase suppression, dimeric binding) and broadened the client repertoire to Akt, IKK, LKB1, Aurora B and a Hsp90-independent viral RT, plus a CK2-Cdc37 feedback loop.","evidence":"ATPase assays, analytical ultracentrifugation, co-IP, gel filtration, purified-protein binding, site-directed phosphomutants","pmids":["11916974","11864612","12176997","12489981","12374737","12435747","11986322"],"confidence":"High","gaps":["Structural basis of ATPase suppression not yet visualized","How phosphorylation controls binding mechanistically unknown"]},{"year":2003,"claim":"Revealed Hsp90-independent client maturation (Spc1) and mapped client-determining motifs, refining how CDC37 selectively engages kinases.","evidence":"Genetic screens, co-IP, kinase and stress-signaling assays (fission yeast)","pmids":["12861001"],"confidence":"High","gaps":["Generality of HSP90-independent function unclear","Structural determinant of client selectivity not defined"]},{"year":2004,"claim":"Solved the crystal structure of the HSP90 N-domain/CDC37 core complex, defining at atomic resolution how CDC37 inserts an arginine into the ATP pocket and fixes the lid open to arrest the ATPase cycle, and delineated CDC37's three-domain organization and kinase N-lobe recognition.","evidence":"X-ray crystallography, SAXS, limited proteolysis/MS domain mapping, scanning mutagenesis, ATPase and binding assays, CK2 Ser13 phosphorylation mapping","pmids":["14718169","14580204","15258137","15082798","15223329","14742721","12437126"],"confidence":"High","gaps":["Structure of full kinase-bound ternary complex still absent","Conformational state of trapped client not visualized"]},{"year":2006,"claim":"Provided the first 3D view of the full HSP90-CDC37-CDK4 ternary complex and identified the kinase glycine-rich loop as a CDC37 recognition element, connecting client engagement to the ATPase cycle.","evidence":"Single-particle electron microscopy, phage display, LC-MS/MS, chimeric-kinase mutagenesis and co-IP","pmids":["16949366","16611982"],"confidence":"High","gaps":["Resolution insufficient to resolve client unfolding","Atomic contacts within the complex unresolved"]},{"year":2008,"claim":"Defined the regulatory phosphatase arm of the cycle, showing PP5/Ppt1 dephosphorylates pSer13-CDC37 specifically within the ternary HSP90 complex to control client activation and release, and crystallized the CDC37 middle domain identifying Leu-205 for HSP90 binding.","evidence":"Phosphospecific antibodies, in vitro phosphatase assays, genetic knockdown, crystallography, NMR, peptide-array and mutagenesis (multiple clients including PKC)","pmids":["18922470","19073599","19091746","19858214"],"confidence":"High","gaps":["Coupling between dephosphorylation and physical release not structurally resolved","Nucleotide-state preference and inhibitor mechanism only biochemically defined"]},{"year":2012,"claim":"Mapped tyrosine-phosphorylation events on CDC37 and HSP90 that impose directionality on the chaperone cycle, and documented a kinase-independent function in which CDC37 alone can drive HSP90 dissociation and client nuclear translocation.","evidence":"Site-directed phosphotyrosine mutagenesis, co-IP, ATPase assays, TAP, nuclear translocation and reporter assays (ERK5)","pmids":["22727666","23428871"],"confidence":"High","gaps":["Kinases responsible for tyrosine phosphorylation in vivo not fully defined","Generality of kinase-independent translocation role unclear"]},{"year":2013,"claim":"Established that CDC37 directly antagonizes client ATP binding and that ATP-competitive kinase inhibitors compete with CDC37 for the kinase N-lobe, providing a mechanistic rationale for inhibitor-induced client degradation in cancer; also showed CDC37 can stabilize clients with greatly reduced direct HSP90 binding.","evidence":"In vitro ATP-binding/competition assays, co-IP, inhibitor treatment, client degradation assays, HSP90-binding-deficient CDC37 mutants","pmids":["23502424","24292678"],"confidence":"High","gaps":["How CDC37 stabilizes clients without direct HSP90 binding mechanistically unresolved"]},{"year":2016,"claim":"Cryo-EM of the HSP90-CDC37-CDK4 complex revealed the client kinase N-lobe fully unfolded and trapped, with CDC37 mimicking the N-lobe and wedging between lobes, and defined CDC37 as a scanning factor that sorts clients by challenging their conformational stability.","evidence":"Cryo-EM (3.9 Å), NMR, hydrogen-deuterium exchange, client vs non-client binding assays","pmids":["27339980","27105117"],"confidence":"High","gaps":["Snapshot of a single state; dynamics of loading and release not captured","Generality across diverse kinase folds not fully established"]},{"year":2022,"claim":"Full-length cryo-EM structures of RAF1- and BRAFV600E-containing HSP90-CDC37 complexes (the latter with PP5) defined the structural basis of RAF-family discrimination and revealed PP5 activation on the complex performing a comprehensive 'factory reset' dephosphorylation prior to client release.","evidence":"Cryo-EM of full-length complexes, proteomic phosphatase-activity analysis, co-IP","pmids":["36055235","36446791"],"confidence":"High","gaps":["Kinetics of the full load-release cycle not resolved","How diverse non-RAF clients are accommodated structurally unknown"]},{"year":null,"claim":"How CDC37's HSP90-independent chaperone activity operates mechanistically, and how a single cochaperone is tuned to handle the full diversity of its kinase and non-kinase clients, remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["Structural basis of autonomous (HSP90-free) chaperone function undefined","Determinants distinguishing client from non-client across the kinome not exhaustively mapped","In vivo regulation of phospho-switches by upstream kinases incompletely characterized"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0044183","term_label":"protein folding chaperone","supporting_discovery_ids":[7,25,39,55,54]},{"term_id":"GO:0140096","term_label":"catalytic activity, acting on a protein","supporting_discovery_ids":[4,30,31,36]},{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[28,22,50,42]},{"term_id":"GO:0060090","term_label":"molecular adaptor activity","supporting_discovery_ids":[11,10,17]}],"localization":[{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[9]},{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[60]}],"pathway":[{"term_id":"R-HSA-392499","term_label":"Metabolism of proteins","supporting_discovery_ids":[4,39,54,55]},{"term_id":"R-HSA-1640170","term_label":"Cell Cycle","supporting_discovery_ids":[0,2,4,56]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[11,21,34,45]},{"term_id":"R-HSA-9612973","term_label":"Autophagy","supporting_discovery_ids":[46,49]},{"term_id":"R-HSA-5357801","term_label":"Programmed Cell Death","supporting_discovery_ids":[53]},{"term_id":"R-HSA-168256","term_label":"Immune System","supporting_discovery_ids":[21,34,53]}],"complexes":["HSP90-CDC37 cochaperone complex","IKK complex"],"partners":["HSP90","CDK4","CDK6","RAF1","AKT","PP5","STI1","CSNK2 (CK2)"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q16543","full_name":"Hsp90 co-chaperone Cdc37","aliases":["Hsp90 chaperone protein kinase-targeting subunit","p50Cdc37"],"length_aa":378,"mass_kda":44.5,"function":"Co-chaperone that binds to numerous kinases and promotes their interaction with the Hsp90 complex, resulting in stabilization and promotion of their activity (PubMed:8666233). Inhibits HSP90AA1 ATPase activity (PubMed:23569206)","subcellular_location":"Cytoplasm","url":"https://www.uniprot.org/uniprotkb/Q16543/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":true,"resolved_as":"","url":"https://depmap.org/portal/gene/CDC37","classification":"Common Essential","n_dependent_lines":1174,"n_total_lines":1208,"dependency_fraction":0.9718543046357616},"opencell":{"profiled":true,"resolved_as":"","ensg_id":"ENSG00000105401","cell_line_id":"CID000010","localizations":[{"compartment":"cytoplasmic","grade":3},{"compartment":"nucleoplasm","grade":2}],"interactors":[{"gene":"CDK11B","stoichiometry":10.0},{"gene":"FKBP5","stoichiometry":10.0},{"gene":"LIMK2","stoichiometry":10.0},{"gene":"CDK9","stoichiometry":4.0},{"gene":"CLK3","stoichiometry":4.0},{"gene":"ARAF","stoichiometry":0.2},{"gene":"AURKB","stoichiometry":0.2},{"gene":"CAD","stoichiometry":0.2},{"gene":"CAPZB","stoichiometry":0.2},{"gene":"CHEK1","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/target/CID000010","total_profiled":1310},"omim":[{"mim_id":"621316","title":"HSP90AB1-ASSOCIATED LONG NONCODING RNA 1; HSALR1","url":"https://www.omim.org/entry/621316"},{"mim_id":"620394","title":"PROTEIN SERINE KINASE H2; PSKH2","url":"https://www.omim.org/entry/620394"},{"mim_id":"616049","title":"TRANSLOCASE OF OUTER MITOCHONDRIAL MEMBRANE 34; TOMM34","url":"https://www.omim.org/entry/616049"},{"mim_id":"610346","title":"CELL DIVISION CYCLE 37-LIKE 1; CDC37L1","url":"https://www.omim.org/entry/610346"},{"mim_id":"608309","title":"PTEN-INDUCED KINASE 1; PINK1","url":"https://www.omim.org/entry/608309"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Supported","locations":[{"location":"Cytosol","reliability":"Supported"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/CDC37"},"hgnc":{"alias_symbol":["P50CDC37"],"prev_symbol":[]},"alphafold":{"accession":"Q16543","domains":[{"cath_id":"1.20.58.610","chopping":"141-280","consensus_level":"high","plddt":90.4267,"start":141,"end":280},{"cath_id":"-","chopping":"293-338","consensus_level":"high","plddt":82.6435,"start":293,"end":338},{"cath_id":"1.10.287","chopping":"23-114","consensus_level":"high","plddt":87.5536,"start":23,"end":114}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q16543","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q16543-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q16543-F1-predicted_aligned_error_v6.png","plddt_mean":81.0},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=CDC37","jax_strain_url":"https://www.jax.org/strain/search?query=CDC37"},"sequence":{"accession":"Q16543","fasta_url":"https://rest.uniprot.org/uniprotkb/Q16543.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q16543/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q16543"}},"corpus_meta":[{"pmid":"12176997","id":"PMC_12176997","title":"Akt forms an intracellular complex with heat shock protein 90 (Hsp90) and Cdc37 and is destabilized by inhibitors of Hsp90 function.","date":"2002","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/12176997","citation_count":558,"is_preprint":false},{"pmid":"8666233","id":"PMC_8666233","title":"Mammalian p50Cdc37 is a protein kinase-targeting subunit of Hsp90 that binds and stabilizes Cdk4.","date":"1996","source":"Genes & development","url":"https://pubmed.ncbi.nlm.nih.gov/8666233","citation_count":444,"is_preprint":false},{"pmid":"11864612","id":"PMC_11864612","title":"TNF-induced recruitment and activation of the IKK complex require Cdc37 and Hsp90.","date":"2002","source":"Molecular cell","url":"https://pubmed.ncbi.nlm.nih.gov/11864612","citation_count":328,"is_preprint":false},{"pmid":"27339980","id":"PMC_27339980","title":"Atomic structure of Hsp90-Cdc37-Cdk4 reveals that Hsp90 traps and stabilizes an unfolded 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Mass.)","url":"https://pubmed.ncbi.nlm.nih.gov/24869908","citation_count":32,"is_preprint":false},{"pmid":"11413142","id":"PMC_11413142","title":"Identification and characterization of Harc, a novel Hsp90-associating relative of Cdc37.","date":"2001","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/11413142","citation_count":32,"is_preprint":false},{"pmid":"22199355","id":"PMC_22199355","title":"Cdc37/Hsp90 protein-mediated regulation of IRE1α protein activity in endoplasmic reticulum stress response and insulin synthesis in INS-1 cells.","date":"2011","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/22199355","citation_count":32,"is_preprint":false},{"pmid":"12437126","id":"PMC_12437126","title":"The Hsp90 co-chaperones Cdc37 and Sti1 interact physically and genetically.","date":"2002","source":"Biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/12437126","citation_count":31,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":46457,"output_tokens":14682,"usd":0.179801,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":27015,"output_tokens":5564,"usd":0.137088,"stage2_stop_reason":"end_turn"},"total_usd":0.316889,"stage1_batch_id":"msgbatch_01ACAxJQabDsht39JXeWG22d","stage2_batch_id":"msgbatch_01QEU22A9U5sbPTgsMzTmvSf","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 1983,\n      \"finding\": \"CDC37 is an essential gene in Saccharomyces cerevisiae required for function at Start, the controlling event of the cell division cycle; the CDC37 locus was isolated, transcriptionally characterized, and mapped.\",\n      \"method\": \"Genetic complementation, plasmid library screening, R-loop analysis, Northern blotting\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic isolation and transcriptional characterization in yeast, single lab, foundational but limited functional mechanistic detail\",\n      \"pmids\": [\"6346060\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1994,\n      \"finding\": \"Drosophila Cdc37 (E(sev)3B) is required for signaling by the Sevenless receptor tyrosine kinase; mutations in cdc37 dominantly enhance mutations in Dmcdc2, linking Cdc37 to both RTK signaling and cell cycle kinase regulation.\",\n      \"method\": \"Genetic screen, epistasis analysis, dominant enhancement of Dmcdc2 mutations\",\n      \"journal\": \"Cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic epistasis in Drosophila, ortholog confirmed, multiple kinase interactions demonstrated\",\n      \"pmids\": [\"8020093\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1995,\n      \"finding\": \"Yeast Cdc37 is required for association of the protein kinase Cdc28 with both G1 cyclins (Cln2) and mitotic cyclins (Clb2); loss of Cdc37 function causes decreased Cdc28 activity and reduced cyclin binding.\",\n      \"method\": \"Temperature-sensitive mutant analysis, co-immunoprecipitation, kinase activity assays\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic loss-of-function with biochemical readout (kinase activity, co-IP), yeast ortholog\",\n      \"pmids\": [\"7753858\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1995,\n      \"finding\": \"Vertebrate Cdc37 (first cloned) binds hyaluronan, chondroitin sulfate, and heparin in vitro via glycosaminoglycan-binding motifs, suggesting a role for glycosaminoglycans in cell division control.\",\n      \"method\": \"cDNA cloning, in vitro glycosaminoglycan binding assay, immunoscreening\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single lab, in vitro binding only, functional significance unestablished\",\n      \"pmids\": [\"7608185\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1996,\n      \"finding\": \"Mammalian p50Cdc37 is a protein kinase-targeting subunit of Hsp90 that binds and stabilizes Cdk4; Cdc37 is sufficient to target Hsp90 to Cdk4; the Cdc37/Hsp90 complex associates preferentially with Cdk4 not bound to D-type cyclins and promotes Cdk4 stability.\",\n      \"method\": \"Co-immunoprecipitation, insect cell coexpression, pharmacological Hsp90 inhibition (geldanamycin), half-life measurement\",\n      \"journal\": \"Genes & development\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal methods (co-IP, in vivo and in vitro reconstitution, pharmacological inhibition), replicated across labs\",\n      \"pmids\": [\"8666233\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1996,\n      \"finding\": \"Mammalian CDC37 physically interacts with CDK4 and CDK6 but not with Cdc2, Cdk2, Cdk3, Cdk5, or cyclins; Cdc37 does not directly activate or inhibit Cdk4/cyclin D1 kinase but facilitates complex assembly between Cdk4 and cyclin D1 in vitro; Cdc37 competes with p16 for binding to Cdk4.\",\n      \"method\": \"Yeast two-hybrid, co-immunoprecipitation, in vitro binding and kinase assays, competition assay\",\n      \"journal\": \"Oncogene\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — yeast two-hybrid plus in vitro functional validation, multiple orthogonal methods\",\n      \"pmids\": [\"9150368\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1996,\n      \"finding\": \"CDC37 is required for p60v-src activity and its maintenance in a soluble, biologically active form in yeast; loss of Cdc37 function reduces v-Src-dependent tyrosine phosphorylation and shifts v-Src to urea-solubilized (insoluble) fractions.\",\n      \"method\": \"Temperature-sensitive cdc37 mutant analysis, Western blotting, fractionation, tyrosine phosphorylation assay\",\n      \"journal\": \"Molecular biology of the cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple cdc37 alleles, biochemical fractionation, functional kinase readout\",\n      \"pmids\": [\"8885235\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1997,\n      \"finding\": \"Cdc37 functions as an autonomous molecular chaperone: in vitro it maintains denatured beta-galactosidase in an activation-competent state and stabilizes mature but unstable casein kinase II; in vivo, Cdc37 overexpression compensates for decreased Hsp90 function specifically for v-Src kinase but not for the glucocorticoid receptor, demonstrating chaperone specificity.\",\n      \"method\": \"In vitro refolding assay, in vivo genetic complementation, kinase stability assays\",\n      \"journal\": \"Genes & development\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — in vitro reconstitution plus in vivo genetic assays, multiple client proteins tested\",\n      \"pmids\": [\"9242486\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1997,\n      \"finding\": \"CDC37 is required for proper spindle pole body (SPB) duplication in yeast; CDC37 was identified as a multicopy suppressor of mps1-1; in cdc37-1 mutants, Mps1 kinase activity is markedly reduced despite normal Mps1 protein levels, indicating CDC37 is required for Mps1 kinase activity.\",\n      \"method\": \"Multicopy suppressor screen, genetic epistasis, kinase activity assay, electron microscopy\",\n      \"journal\": \"The Journal of cell biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic suppressor screen, biochemical kinase assay, structural phenotype by EM\",\n      \"pmids\": [\"9060463\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1997,\n      \"finding\": \"p50 (mammalian Cdc37) is the 50-kDa protein in Raf-1 and pp60(v-src) complexes; immunocytochemistry shows primarily cytoplasmic localization around the nuclear membrane.\",\n      \"method\": \"Protein purification, peptide sequencing, cDNA cloning, co-immunoprecipitation, immunocytochemistry\",\n      \"journal\": \"Biochemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — protein identification confirmed by multiple methods (sequencing, cloning, co-IP, ICC), single lab\",\n      \"pmids\": [\"9132011\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1998,\n      \"finding\": \"p50(cdc37) binds directly to the catalytic domain of Raf (sufficient for interaction); p50(cdc37) binds to a site on Hsp90 topologically adjacent to but distinct from the TPR acceptor site; p50(cdc37) and TPR domain proteins form mutually exclusive complexes with Hsp90.\",\n      \"method\": \"Co-immunoprecipitation, direct binding assays, competition assays with TPR domain proteins\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — direct binding mapping, mutual exclusivity assays, multiple orthogonal approaches\",\n      \"pmids\": [\"9685350\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1999,\n      \"finding\": \"p50(cdc37) is the primary determinant of Hsp90 recruitment to Raf-1; coexpression of p50(cdc37) with Raf-1 activates Raf-1 in Sf9 cells; a p50(cdc37) mutant unable to recruit Hsp90 inhibits Raf-1 and MAPK activation; formation of a ternary Raf-1–p50(cdc37)–Hsp90 complex is required for Raf-1 kinase activity.\",\n      \"method\": \"Baculovirus coexpression, dominant-negative mutant, geldanamycin treatment, kinase activity assay\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — dominant-negative and pharmacological inhibition with multiple kinase readouts, Sf9 reconstitution\",\n      \"pmids\": [\"10022854\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1999,\n      \"finding\": \"Cdc37 is required for activity of the yeast kinase Ste11; Cdc37, Ste11, and Hsp90 co-precipitate pairwise; loss of Cdc37 impairs pheromone signaling and Ste11 accumulation/functional maturation, establishing Ste11 as the first endogenous Cdc37 client in yeast.\",\n      \"method\": \"Genetic cdc37 mutant analysis, co-immunoprecipitation, pheromone signaling assays\",\n      \"journal\": \"FEBS letters\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — co-IP plus functional genetic assay, single lab\",\n      \"pmids\": [\"10664467\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1999,\n      \"finding\": \"ZAP70 kinase domain mutant (M572L) is bound and restored by Cdc37 overexpression; this restoration requires functional HSP90; Cdc37 acts as a molecular chaperone for a temperature-sensitive kinase domain mutant of ZAP70.\",\n      \"method\": \"Mutant ZAP70 expression, Cdc37 overexpression rescue, co-immunoprecipitation, kinase activity assay\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — co-IP and functional rescue with defined mutant, single lab\",\n      \"pmids\": [\"10574909\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"Cdc37 promotes stability of both Cdc28 and Cak1 kinases in yeast; pulse-chase analysis shows Cdc28 and Cak1 are destabilized when Cdc37 function is absent during (but not after) translation, indicating a cotranslational role in kinase folding.\",\n      \"method\": \"Temperature-sensitive mutant, pulse-chase analysis, co-expression in insect cells, kinase activity assay\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — pulse-chase kinetics, insect cell coexpression, multiple kinase substrates, yeast ortholog\",\n      \"pmids\": [\"10629030\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"p50(cdc37) is a nonexclusive Hsp90 cochaperone found in immunoadsorptions with multiple cochaperones (FKBP52, cyp40, p60HOP, Hsp70, p23); it participates in Hsp90-mediated folding of immature kinase molecules and responds to Hsp90's nucleotide-regulated conformational switching.\",\n      \"method\": \"Co-immunoprecipitation with multiple antibodies, salt-stability assay, geldanamycin treatment\",\n      \"journal\": \"Biochemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple co-IP approaches, nucleotide-state dependency shown, single lab\",\n      \"pmids\": [\"10858314\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"Cdc37 functionally interacts with human androgen receptor (AR) via its ligand-binding domain but not with glucocorticoid receptor; dominant-negative Cdc37 downregulates full-length AR; Cdc37 has broader polypeptide client specificity than kinases alone.\",\n      \"method\": \"Reticulocyte lysate binding assay, yeast model, dominant-negative overexpression, immunoprecipitation\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple orthogonal assays (reticulocyte, yeast, mammalian cells), single lab\",\n      \"pmids\": [\"11085988\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"p50(cdc37) interacts co-translationally with nascent HRI kinase chains; the N-terminal domain of p50(cdc37) binds immature HRI while the C-terminal region binds Hsp90; p50(cdc37) stimulates HRI activation in response to heme deficiency; geldanamycin disrupts both Hsp90 and p50(cdc37) binding to HRI, indicating that Hsp90's nucleotide conformation regulates p50(cdc37)'s kinase-binding activity.\",\n      \"method\": \"Reticulocyte lysate translation, co-immunoprecipitation, domain mapping with truncation mutants, geldanamycin treatment, kinase activity assay\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — co-translational interaction defined, domain mapping, functional kinase assay, nucleotide-state dependency\",\n      \"pmids\": [\"11036079\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"Cdc37 co-immunoprecipitates with MOK kinase along with Hsp90, Hsc70, Hsp70, and Hsp60 but not GRP94, FKBP52, or Hop; kinase catalytic subdomains I-IV are required for Hsp90 binding.\",\n      \"method\": \"Co-immunoprecipitation, deletion mutant mapping, geldanamycin-induced degradation assay\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — co-IP with domain mapping, multiple related kinases tested, single lab\",\n      \"pmids\": [\"11278794\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"Cdc37 (p50/CDC37) is a novel interaction partner of the duck hepatitis B virus reverse transcriptase (RT); p50 binds the RT independently of Hsp90 (demonstrated with p50deltaC mutant); this interaction is required for reverse transcription initiation in vitro and for viral DNA replication and RNA packaging in transfected cells.\",\n      \"method\": \"Co-immunoprecipitation, pull-down assay (in vitro and in vivo), purified protein direct interaction, functional reverse transcription assay, viral replication assay\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — purified protein direct binding, in vitro functional assay, cell-based replication assay, Hsp90-independent activity demonstrated\",\n      \"pmids\": [\"11986322\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"Intracellular Akt forms a complex with Hsp90 and Cdc37; Hsp90 inhibition causes ubiquitination and proteasomal degradation of Akt, shortening its half-life from 36 to 12 h; Akt and PDK1 are the only PKA/PKB/PKC-family members affected by Hsp90 inhibitors.\",\n      \"method\": \"Co-immunoprecipitation, Hsp90 inhibitor (geldanamycin) treatment, pulse-chase half-life measurement, ubiquitination assay, proteasome inhibitor\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — co-IP, pulse-chase kinetics, proteasome pathway defined, multiple orthogonal methods\",\n      \"pmids\": [\"12176997\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"Cdc37 and Hsp90 are components of the ~900 kDa IKK complex; Cdc37 directly binds Hsp90 and directly binds the kinase domain of IKKα/IKKβ; geldanamycin disrupts this heterocomplex, preventing TNF-induced IKK activation, NF-κB activation, and IKK recruitment to TNF-R1.\",\n      \"method\": \"Co-immunoprecipitation, direct binding assay, gel filtration, geldanamycin treatment, NF-κB reporter assay, membrane recruitment assay\",\n      \"journal\": \"Molecular cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — direct interaction mapping, multiple functional readouts, complex stoichiometry defined\",\n      \"pmids\": [\"11864612\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"Cdc37p/p50(cdc37) suppresses Hsp90 ATPase activity (like Sti1/Hop/p60); Cdc37p binds Hsp90 as a dimer; suppressed ATPase is restored by immunophilin cochaperone Cpr6/Cyp40; unlike Sti1, Cdc37p forms a stable complex with geldanamycin-bound Hsp90.\",\n      \"method\": \"ATPase activity assay, analytical ultracentrifugation, geldanamycin displacement assay\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — in vitro ATPase assay with defined mechanistic outcome, dimerization established, replicated across labs\",\n      \"pmids\": [\"11916974\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"In yeast, CDC37 is a multicopy suppressor of CKII (cka2-13ts); Cdc37 is a physiological substrate of CKII, phosphorylated at Ser-14 and/or Ser-17; cdc37-S14,17A strains show severe growth defects and reduced CKII activity, and CKII activity is elevated at cell cycle phases requiring Cdc37; this defines a positive feedback loop between CKII and Cdc37.\",\n      \"method\": \"Multicopy suppressor screen, metabolic labeling + immunoprecipitation, site-directed mutagenesis (S14A, S17A, S14,17E), CKII kinase activity assay\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic suppressor, site-specific phosphomutants, kinase activity assay, multiple alleles\",\n      \"pmids\": [\"12435747\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"Cdc37 is essential for chromosome segregation and cytokinesis in Drosophila; Cdc37 loss-of-function phenotypes closely resemble Aurora B inactivation; Aurora B interacts with and requires the Cdc37/Hsp90 complex for stability.\",\n      \"method\": \"Drosophila genetics (loss-of-function), epistasis, co-immunoprecipitation, mitosis/meiosis phenotype analysis\",\n      \"journal\": \"The EMBO journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic epistasis in metazoan model, co-IP, Aurora B identified as Cdc37/Hsp90 client\",\n      \"pmids\": [\"12374737\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"The protein kinase-binding domain of Cdc37 alone is sufficient for yeast cell viability, for efficient MAP kinase pathway signaling, and for partial v-Src folding independent of Hsp90; CDC37 overexpression suppresses Sti1 deletion defects in v-Src folding.\",\n      \"method\": \"CDC37 truncation mutants, yeast viability assay, MAP kinase signaling reporter, v-Src folding assay\",\n      \"journal\": \"The Journal of cell biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple truncation mutants, cell viability and biochemical assays, Hsp90-independent activity demonstrated\",\n      \"pmids\": [\"12499358\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"Hsp90 and Cdc37 interact with the kinase domain of LKB1 and regulate LKB1 stability; Hsp90 inhibitors (geldanamycin, novobiocin) cause proteasomal ubiquitination and degradation of LKB1; a sporadic testicular cancer point mutation in LKB1 weakens interaction with both Hsp90 and Cdc37.\",\n      \"method\": \"LKB1 purification, co-immunoprecipitation, Hsp90 inhibitor treatment, ubiquitination assay, cancer mutation analysis\",\n      \"journal\": \"The Biochemical journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — purification, direct co-IP, pharmacological inhibition, mutational analysis, proteasomal pathway defined\",\n      \"pmids\": [\"12489981\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"Cdc37 is a positive regulator of Spc1 SAPK in fission yeast; Cdc37 physically interacts with Spc1; cdc37 mutation reduces Spc1 protein levels and stress-induced Spc1 phosphorylation by Wis1 MAPKK; Hsp90 mutation does not affect Spc1, indicating a Hsp90-independent function of Cdc37 for this client.\",\n      \"method\": \"Genetic screen, co-immunoprecipitation, kinase assay, stress signaling reporter assay\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic screen, co-IP, phosphorylation assay, Hsp90-independent result validated\",\n      \"pmids\": [\"12861001\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"Crystal structure of the Hsp90 N-domain/Cdc37 core complex reveals that dimeric p50(cdc37) binds surfaces of the Hsp90 N-domain implicated in ATP-dependent N-terminal dimerization; Cdc37 inserts an arginine side chain into the ATP binding pocket to disable catalysis and fixes the lid in an open conformation, arresting the Hsp90 ATPase cycle during client-protein loading.\",\n      \"method\": \"X-ray crystallography, ATPase activity assay, mutagenesis\",\n      \"journal\": \"Cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — crystal structure plus biochemical validation, mechanism of ATPase inhibition defined at atomic level\",\n      \"pmids\": [\"14718169\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"Mammalian CK2 phosphorylates Cdc37 at Ser13 in vitro and in vivo; Ser13 is the unique in vivo phosphorylation site; CK2 phosphorylation of Ser13 is essential for Cdc37's optimal binding to multiple kinase clients (Raf1, Akt, Aurora-B, Cdk4, Src, MOK, MAK, MRK) and for recruitment of Hsp90 to kinase-Cdc37 complexes.\",\n      \"method\": \"In vitro kinase assay with purified CK2, site-directed mutagenesis, in vivo phosphorylation (metabolic labeling), co-immunoprecipitation, CK2 inhibitor treatment\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — in vitro kinase assay, unique phosphorylation site confirmed in vivo, multiple kinase clients tested, CK2 inhibitor validation\",\n      \"pmids\": [\"15082798\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"Cdc37 comprises three discrete structural domains by limited proteolysis: N-terminal domain (residues 1-126) binds client kinases; middle domain (residues 128-282) binds Hsp90; C-terminal domain (283-378) has no ascribed function; residues S127-G163 serve as an interdomain switch; W7A and scanning alanine mutagenesis identified N-terminal residues critical for high-affinity kinase binding.\",\n      \"method\": \"Limited proteolysis, MALDI-TOF MS, peptide microsequencing, domain truncation, scanning alanine mutagenesis, functional binding assay\",\n      \"journal\": \"Biochemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — proteolysis + MS domain mapping, mutagenesis with functional validation\",\n      \"pmids\": [\"14580204\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"Cdc37 recognizes alpha-C-helix and beta4-beta5 strands of the kinase N-lobe as primary binding determinants; Hsp90 requires interaction with adjacent subdomain structures spanning both N- and C-lobes to form high-affinity complexes; Cdc37 interacts only with the N-lobe of kinase catalytic domains.\",\n      \"method\": \"Crystal structure-guided kinase construct design, pull-down assay, salt-stability binding assay, molybdate-independent binding assay\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — structure-guided mutagenesis, in vitro binding assay with defined lobe constructs, single lab\",\n      \"pmids\": [\"15258137\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"Cdc37 and Sti1 physically interact directly (without Hsp90); the combination of cdc37 and sti1 mutations is synthetically lethal in yeast; Cdc37 overexpression suppresses sti1 deletion and restores stable Hsp90 binding to Ste11.\",\n      \"method\": \"GST pull-down with purified proteins, co-immunoprecipitation, synthetic lethality screen, genetic suppression\",\n      \"journal\": \"Molecular biology of the cell / Biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct protein-protein interaction, genetic epistasis, single lab\",\n      \"pmids\": [\"14742721\", \"12437126\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"SAXS solution structure of human Hsp90β-Cdc37 complex shows that a Cdc37 dimer binds the two N-terminal domain/linker regions of the Hsp90 dimer, fixing them in a single conformation suitable for client protein recognition.\",\n      \"method\": \"Small angle X-ray scattering (SAXS), biochemical characterization\",\n      \"journal\": \"Journal of molecular biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — SAXS structural data, single lab, limited functional validation\",\n      \"pmids\": [\"15223329\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"JAK1 (but not JAK2) interacts with Hsp90 and CDC37; both interactions are destabilized by Hsp90 inhibitors; CDC37 and Hsp90 are required for interferon type I and II signaling through stabilization of JAK1.\",\n      \"method\": \"Co-immunoprecipitation, siRNA knockdown, Hsp90 inhibitor treatment, interferon signaling assay (STAT1 phosphorylation, antiviral response)\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — co-IP, siRNA, and pharmacological evidence, single lab\",\n      \"pmids\": [\"16280321\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"Single-particle electron microscopy of the Hsp90-Cdc37-Cdk4 ternary complex defines its 3D structure and stoichiometry; comparison with Hsp90 crystal structure localizes Cdc37 and Cdk4 positions and suggests conformational changes in kinase coupled to Hsp90 ATPase cycle.\",\n      \"method\": \"Complex purification, stoichiometry determination, single-particle electron microscopy, crystal structure comparison\",\n      \"journal\": \"Molecular cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — EM structure of full ternary complex, stoichiometry defined, structural mechanistic model\",\n      \"pmids\": [\"16949366\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"Cdc37 interacts with the glycine-rich loop (GXFG motif in canonical GXGXXG) of protein kinase N-lobes; the GSGSFG motif of Raf-1 is necessary for Cdc37 association; the C-terminal portions of kinases determine differential affinity for Cdc37; an unphosphorylated activation segment threonine in non-client kinases permits transient Cdc37 interaction.\",\n      \"method\": \"Phage display, LC-MS/MS, deletion and chimeric kinase mutants, co-immunoprecipitation\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — phage display identifies motif, confirmed by mutagenesis and co-IP, multiple kinases tested\",\n      \"pmids\": [\"16611982\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"In C. elegans embryos, CDC-37 (Cdc37 homolog) is required for establishment phase of embryonic polarity; CDC-37 reduction allows PAR-3-independent cortical accumulation of PAR-6 and PKC-3; CDC-37 acts by maintaining PKC-3 levels and influencing other client proteins; two sites for PAR-6 cortical association are revealed.\",\n      \"method\": \"RNAi knockdown (cdc-37), live imaging, immunofluorescence, epistasis with par mutants\",\n      \"journal\": \"Development (Cambridge, England)\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — RNAi loss-of-function with specific polarity phenotype, epistasis analysis, C. elegans ortholog\",\n      \"pmids\": [\"16943281\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"Cdc37 is required for Ste11-mediated pheromone signaling in yeast; Cdc37 matures de novo synthesized IKKs into enzymatically competent kinases; Cdc37 recruits Hsp90 to the IKK complex transiently and preferentially via IKKα; Cdc37 binding is conferred by both N-terminal and C-terminal residues.\",\n      \"method\": \"RNAi knockdown, IKK kinase maturation assay, co-immunoprecipitation, domain mapping\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — RNAi and domain mapping, functional kinase maturation assay, single lab\",\n      \"pmids\": [\"17728246\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"Cdc37 is required for stability of ~50% of the yeast kinome (51/65 kinases tested); pulse-labeling shows Cdc37 protects nascent kinase chains from rapid cotranslational degradation; kinase abundance can be restored at reduced temperature without fully restoring activity.\",\n      \"method\": \"Large-scale kinase abundance measurement in cdc37 mutant yeast, pulse-chase labeling, temperature-shift experiments\",\n      \"journal\": \"The Journal of cell biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genome-scale analysis with pulse-chase validation, demonstrates general cotranslational chaperone role\",\n      \"pmids\": [\"17242065\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"Pink1 kinase is a novel Cdc37/Hsp90 client kinase; the Cdc37/Hsp90 chaperone system influences both the subcellular distribution and the 66/55 kDa protein ratio of Pink1; PD-causing Pink1 mutations decrease while Parkin expression increases the Pink1 66/55 kDa ratio.\",\n      \"method\": \"Mass spectrometry of immunoisolated Pink1 complexes, co-immunoprecipitation, Hsp90 inhibitor treatment, subcellular fractionation\",\n      \"journal\": \"Human molecular genetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — unbiased MS identification, co-IP confirmation, functional consequences of chaperone disruption shown\",\n      \"pmids\": [\"18003639\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"Aurora B kinase requires Cdc37/Hsp90 complex for stability (confirmed in Drosophila); MLK3 associates with Hsp90 and p50(cdc37) through its catalytic domain; geldanamycin reduces MLK3 levels and blocks TNF-α-induced MLK3 and JNK activation.\",\n      \"method\": \"Co-immunoprecipitation, affinity purification with LC-MS/MS identification, geldanamycin treatment, kinase activity assay\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — affinity purification + MS + co-IP, functional kinase readout, single lab\",\n      \"pmids\": [\"15001580\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"Cdc37 Ser13 phosphorylation is constitutive in uncomplexed Cdc37, in binary kinase-Cdc37 complex, and in ternary Hsp90-Cdc37-kinase complex; PP5/Ppt1 phosphatase specifically dephosphorylates pSer13-Cdc37 when in the ternary Hsp90 complex but not isolated Cdc37; this targeted dephosphorylation directly regulates activation of kinase clients by Hsp90-Cdc37.\",\n      \"method\": \"Phosphospecific antibodies, in vitro phosphatase assay, yeast and human tumor cell co-immunoprecipitation, PP5/Ppt1 genetic knockdown, kinase client activation assay\",\n      \"journal\": \"Molecular cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — in vitro phosphatase assay, validated in two organisms, complex-specific dephosphorylation mechanism defined\",\n      \"pmids\": [\"18922470\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"Conventional and novel (but not atypical) PKC isozymes bind Cdc37 and Hsp90 through a conserved PXXP motif in the C-terminal tail; mutation of both Pro-616 and Pro-619 abolishes PKC phosphorylation and activity; Hsp90 and Cdc37 inhibitors reduce the rate of PKC processing phosphorylation; Hsp90 binding regions on PKC are identified around the PXXP segment via peptide array overlay.\",\n      \"method\": \"Co-immunoprecipitation, site-directed mutagenesis (PXXP and Tyr-446 to Ala), Hsp90/Cdc37 inhibitor treatment, peptide array overlay, processing phosphorylation assay\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — mutagenesis defining binding motif, peptide array, functional phosphorylation assay, multiple PKC isozymes\",\n      \"pmids\": [\"19091746\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"Celastrol disrupts Hsp90-Cdc37 interaction by binding to the Hsp90 C-terminal domain (not the ATP pocket), protecting it from trypsin digestion; Cdc37 binds ADP-bound/nucleotide-free Hsp90 but not ATP-bound Hsp90; classical Hsp90 inhibitors (geldanamycin) do not disrupt Hsp90-Cdc37 interaction.\",\n      \"method\": \"GST pull-down, ELISA, proteolytic fingerprinting, celastrol binding assay, ATPase assay\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — in vitro reconstitution, multiple biochemical methods, Cdc37 nucleotide-state preference mapped\",\n      \"pmids\": [\"19858214\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"Hsp90-Cdc37 complex is part of the p38α signaling complex; Cdc37 directly binds p38α; Cdc37 expression is sufficient and necessary to suppress noncanonical p38α autophosphorylation but has no impact on canonical MKK3-mediated p38 activation.\",\n      \"method\": \"Proteomics + biochemical co-immunoprecipitation, Cdc37 knockdown/overexpression, p38 activation assay (autophosphorylation vs canonical), cardiomyocyte system\",\n      \"journal\": \"Circulation research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — proteomic discovery confirmed by co-IP, gain- and loss-of-function with specific mechanistic discrimination\",\n      \"pmids\": [\"20299663\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"Hsp90-Cdc37 complex stabilizes and activates Ulk1 kinase; Ulk1-Hsp90-Cdc37 interaction is required for phosphorylation and release of Atg13 from Ulk1 and for Atg13 recruitment to damaged mitochondria; Hsp90-Cdc37, Ulk1, and Atg13 phosphorylation are all required for efficient mitophagy.\",\n      \"method\": \"Co-immunoprecipitation, Hsp90 inhibitor treatment, Cdc37 knockdown, mitophagy assay, phosphorylation analysis\",\n      \"journal\": \"Molecular cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — pathway defined by co-IP, pharmacological and genetic loss-of-function, specific mitophagy readout\",\n      \"pmids\": [\"21855797\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"Cdc37 co-localizes with tau in neuronal cells and physically interacts with tau from human brain; Cdc37 suppression destabilizes tau and alters its phosphorylation profile by reducing levels of specific tau kinases (Cdk5, Akt) without affecting others (GSK3β, Mark2); Cdc37 overexpression prevents tau clearance following Hsp90 inhibition.\",\n      \"method\": \"Co-immunoprecipitation from human brain, immunofluorescence colocalization, Cdc37 siRNA knockdown/overexpression, tau kinase level and phosphorylation analysis\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct interaction from human brain tissue, functional consequences with gain and loss of function, single lab\",\n      \"pmids\": [\"21367866\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"Cdc37 directly interacts with IRE1α through a conserved cytosolic motif; Cdc37 knockdown or disruption of Cdc37-IRE1α interaction increases basal IRE1α kinase activity; Cdc37-mediated Hsp90/Cdc37 interaction with IRE1α maintains basal IRE1α activity and contributes to normal insulin synthesis and secretion.\",\n      \"method\": \"Co-immunoprecipitation, Cdc37 siRNA knockdown, IRE1α activity assay, insulin synthesis/secretion measurement\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — co-IP, siRNA, functional IRE1α activity assay, single lab\",\n      \"pmids\": [\"22199355\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"Cdc37 disruption triggers autophagic clearance of TDP-43; Cdc37 depletion causes proteolytic cleavage and nuclear retrotranslocation of TDP-43 followed by autophagic uptake; tau accumulation prevents clearance of cleaved TDP-43.\",\n      \"method\": \"Cdc37 siRNA knockdown, Hsp90 inhibitor treatment, TDP-43 localization assay, autophagy pathway analysis (beclin1 knockdown)\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — siRNA and pharmacological with defined pathway, multiple mechanistic steps defined, single lab\",\n      \"pmids\": [\"22674575\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"Tyrosine phosphorylation of p50(Cdc37) at Y4 and Y298 disrupts client-p50(Cdc37) association; Hsp90 phosphorylation at Y197 dissociates p50(Cdc37) from Hsp90; these phosphorylation events provide directionality to the chaperone cycle; subsequent Hsp90 Y313 phosphorylation promotes AHA1 recruitment.\",\n      \"method\": \"Site-directed mutagenesis of phosphotyrosine sites, co-immunoprecipitation, in vitro phosphorylation, ATPase assay\",\n      \"journal\": \"Molecular cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — mutagenesis of specific tyrosines, mechanistic ordering of chaperone cycle events, multiple orthogonal methods\",\n      \"pmids\": [\"22727666\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"Cdc37 directly antagonizes ATP binding to client kinases; ATP-competitive kinase inhibitors (vemurafenib, lapatinib) block Cdc37 binding to client kinases such as B-Raf and ErbB2, depriving them of access to the Hsp90-Cdc37 complex and causing their degradation in cancer cells.\",\n      \"method\": \"In vitro ATP binding assay, co-immunoprecipitation, kinase inhibitor treatment, client kinase degradation assay\",\n      \"journal\": \"Nature chemical biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — in vitro ATP binding antagonism demonstrated, mechanistic link to kinase degradation in cells established\",\n      \"pmids\": [\"23502424\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"ERK5 interacts with Hsp90-Cdc37 in resting cells; activation of ERK5 induces Hsp90 dissociation from the ERK5-Cdc37 complex via ERK5 C-tail autophosphorylation, leading to nuclear translocation; Cdc37 overexpression alone induces Hsp90 dissociation and nuclear translocation of kinase-inactive ERK5, demonstrating Cdc37-driven kinase-independent transcriptional activity.\",\n      \"method\": \"Tandem affinity purification, co-immunoprecipitation, Hsp90/Cdc37 inhibition, nuclear translocation assay, transcriptional reporter\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — TAP identification, co-IP, gain/loss-of-function, novel kinase-independent Cdc37 mechanism defined\",\n      \"pmids\": [\"23428871\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"RIP3 kinase activation during necroptosis requires a physical association with the HSP90-CDC37 cochaperone complex; CDC37 knockdown prevents cells from responding to necroptosis stimuli; HSP90 inhibitors block RIP3 activation and prevent systemic inflammatory response syndrome in TNF-α-treated rats.\",\n      \"method\": \"Co-immunoprecipitation, CDC37 siRNA knockdown, HSP90 inhibitor treatment, necroptosis assay, in vivo rat SIRS model\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — co-IP, genetic knockdown, pharmacological inhibition, in vivo validation\",\n      \"pmids\": [\"25852146\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"Cryo-EM structure of the Hsp90-Cdc37-Cdk4 complex at 3.9 Å reveals that the two lobes of Cdk4 are completely separated with the β4-β5 sheet unfolded; Cdc37 mimics part of the kinase N-lobe, stabilizing an open kinase conformation by wedging between the two lobes; Hsp90 clamps around the unfolded kinase β5 strand, protecting it in a trapped unfolded state.\",\n      \"method\": \"Cryo-electron microscopy (3.9 Å), complex reconstitution\",\n      \"journal\": \"Science (New York, N.Y.)\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — near-atomic resolution cryo-EM structure, first full-length complex structure, mechanistic model validated by extensive prior biochemical data\",\n      \"pmids\": [\"27339980\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"Cdc37 acts as a general kinase scanning factor that participates in selective client recruitment by challenging the conformational stability of client kinases through local unfolding; stable complex formation requires multidomain cochaperone interface and is accompanied by conformational changes in clients but not nonclients; this metastable conformational state is the basis for Hsp90-dependence.\",\n      \"method\": \"NMR, hydrogen-deuterium exchange, in vitro binding and stability assays, client vs nonclient kinase discrimination assay\",\n      \"journal\": \"Molecular cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — NMR and HDX with functional binding assays, mechanistic model for client sorting defined\",\n      \"pmids\": [\"27105117\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"Assembly of CDK4 and CDK6 into protein complexes is differentially regulated by Cdc37-Hsp90; Cdc37-Hsp90 relinquishes CDK6 to D3- and virus-type cyclins and INK inhibitors, whereas CDK4 is less readily relinquished to cyclins; CIP/KIP CDK inhibitors cooperate with D-type cyclins to form Cdc37-resistant ternary CDK4/6-cyclin complexes.\",\n      \"method\": \"Co-immunoprecipitation, competition binding assay, differential release assay for CDK4 vs CDK6\",\n      \"journal\": \"Cell reports\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal binding assays, differential CDK4/CDK6 regulation established, mechanistic model for assembly factor activity\",\n      \"pmids\": [\"29091774\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"Crystal structure of the 16-kDa middle domain of human Cdc37 at 1.88 Å shows it exists as a monomer; NMR and mutagenesis identify Leu-205 as a key residue for Cdc37-Hsp90 N-domain complex formation.\",\n      \"method\": \"X-ray crystallography (1.88 Å), NMR spectroscopy, site-directed mutagenesis (L205)\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — crystal structure plus NMR and mutagenesis, key residue identified\",\n      \"pmids\": [\"19073599\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"CryoEM structure of the full-length RAF1-HSP90-CDC37 complex reveals that RAF1 kinase N-lobe is unfolded with its hydrophobic core trapped in the HSP90 dimer; CDC37 wraps around HSP90 and interacts with both N- and C-lobes of RAF1; the structure indicates how CDC37 discriminates between different RAF family members; disruption of CDC37-DFG segment interaction reveals pharmacological vulnerabilities for RAF1 degradation.\",\n      \"method\": \"Cryo-electron microscopy (full-length complex), structural analysis\",\n      \"journal\": \"Molecular cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — near-atomic cryo-EM of full-length ternary complex, mechanistic basis for RAF1 regulation and CDC37 selectivity revealed\",\n      \"pmids\": [\"36055235\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"CryoEM structures of the HSP90-CDC37-BRAFV600E-PP5 complex in autoinhibited and activated conformations reveal that PP5 is activated by recruitment to HSP90 complexes; the V600E mutation favors BRAF association with HSP90-CDC37; PP5 comprehensively dephosphorylates client proteins including BRAFV600E and CRAF, removing 14-3-3 interaction sites and performing a 'factory reset' prior to kinase release.\",\n      \"method\": \"CryoEM structure determination, proteomic phosphatase activity analysis, co-immunoprecipitation\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — multiple cryo-EM structures of different complex states, proteomic phosphatase activity validation, mechanism for kinase release defined\",\n      \"pmids\": [\"36446791\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"Cdc37 is present on the cell surface of breast cancer cells where it interacts with surface HSP90, HER2, and EGFR; functional inhibition of surface HSP90 disrupts the Cdc37/HSP90 and Cdc37/ErbB receptor complexes on the cell surface.\",\n      \"method\": \"Cell-impermeable anti-Cdc37 antibody, co-immunoprecipitation, cancer cell motility assay\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — cell surface localization demonstrated with impermeable antibody, co-IP of surface complexes, single lab\",\n      \"pmids\": [\"22912728\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"CDC37 mutants with single/double point mutations at M164 and L205 (greatly reduced HSP90 binding) retain client kinase association and phenocopy wild-type CDC37 in increasing CDK4-HSP90 association and CDK4 levels; CDC37 can stabilize kinase clients through a mechanism not requiring its direct interaction with HSP90, but still requiring HSP90 activity.\",\n      \"method\": \"Site-directed mutagenesis (M164A, L205A, double mutant), co-immunoprecipitation, client kinase level and half-life measurement, siRNA rescue experiment\",\n      \"journal\": \"Oncogene\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — mutagenesis with comprehensive functional validation, HSP90-binding-independent mechanism defined, multiple orthogonal assays\",\n      \"pmids\": [\"24292678\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"CDC37 (p50Cdc37) is a kinase-specific cochaperone of HSP90 that acts as a two-component scaffold: its N-terminal domain directly recognizes and locally unfolds client kinase N-lobes (via the α-C-helix/β4-β5/glycine-rich loop), while its middle domain binds HSP90's N-terminal nucleotide-binding domain, inserting an arginine into the ATP pocket to arrest the HSP90 ATPase cycle during client loading; cryo-EM structures of the Hsp90-Cdc37-Cdk4 and Hsp90-CDC37-RAF1 complexes show the kinase N-lobe is completely unfolded and trapped by HSP90, with CDC37 wedging between the lobes to stabilize this open state; CDC37 Ser13 must be phosphorylated by CK2 for efficient kinase binding, and this phosphorylation is removed by PP5 (recruited to HSP90 complexes) to trigger client release after a 'factory reset' dephosphorylation; tyrosine phosphorylation of CDC37 at Y4/Y298 and of HSP90 at Y197 further regulate client and CDC37 release during cycle progression; ATP-competitive kinase inhibitors directly compete with CDC37 for kinase binding, explaining their ability to deprive oncogenic kinases of chaperone support; beyond kinases, CDC37 also chaperones the hepadnavirus reverse transcriptase and directly stabilizes tau, and it has Hsp90-independent chaperone activity; loss of CDC37 function leads to proteasomal or autophagic degradation of client kinases cotranslationally.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"CDC37 (p50Cdc37) is a kinase-specific cochaperone of HSP90 that selectively recruits, folds, and stabilizes a large fraction of the cellular protein kinome, originally defined as an essential cell-cycle gene acting at Start in yeast and as a regulator of receptor-tyrosine-kinase signaling and cell-cycle kinases in metazoa [#0, #1, #2]. It functions as a two-component scaffold: an N-terminal domain (residues 1–126) recognizes client kinases by engaging the αC-helix/β4-β5 strands and the glycine-rich GXFG loop of the kinase N-lobe, while a middle domain (128–282) docks onto the HSP90 N-terminal domain [#30, #31, #36]. Mechanistically, CDC37 binds the HSP90 N-domain surface required for ATP-dependent dimerization and inserts an arginine into the ATP pocket to arrest the HSP90 ATPase cycle during client loading [#28]. Cryo-EM of the HSP90–CDC37–CDK4 and full-length HSP90–CDC37–RAF1 complexes shows the client kinase N-lobe completely unfolded and trapped within the HSP90 dimer, with CDC37 mimicking part of the N-lobe and wedging between the kinase lobes to stabilize this open state [#54, #58]; CDC37 acts as a general kinase \\\"scanning factor\\\" that discriminates clients from non-clients by challenging their conformational stability through local unfolding [#55]. The cycle is regulated by phosphorylation: CK2 phosphorylation of CDC37 at Ser13 is required for efficient kinase-client binding and HSP90 recruitment [#29], complex-specific dephosphorylation of pSer13 by PP5/Ppt1 triggers client activation and release in a \\\"factory reset\\\" mechanism [#42, #59], and tyrosine phosphorylation of CDC37 (Y4/Y298) and HSP90 (Y197) provides directionality by dissociating client and CDC37 from the chaperone machine [#50]. Through this activity CDC37 stabilizes a broad client set spanning CDK4/CDK6, Raf-1/B-Raf, v-Src, Akt, IKK, JAK1, Aurora B, ULK1, RIP3 and many others, governing cell-cycle progression, MAPK and NF-κB signaling, mitophagy and necroptosis [#4, #11, #20, #21, #24, #46, #53]. CDC37 also retains HSP90-independent chaperone activity, directly binding and maturing certain kinases and non-kinase clients such as the hepadnavirus reverse transcriptase and tau [#7, #19, #25, #47]. Loss of CDC37 function leads to cotranslational proteasomal or autophagic degradation of nascent client kinases [#39, #14]. Because ATP-competitive kinase inhibitors directly compete with CDC37 for the kinase N-lobe, they deprive oncogenic kinases of chaperone support and promote their degradation [#51].\",\n  \"teleology\": [\n    {\n      \"year\": 1983,\n      \"claim\": \"Established CDC37 as an essential gene controlling a discrete cell-cycle decision point, framing the question of which molecular activity underlies this requirement.\",\n      \"evidence\": \"Genetic complementation and transcriptional mapping in S. cerevisiae\",\n      \"pmids\": [\"6346060\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No molecular function assigned\", \"No protein partners identified\", \"Connection to kinases not yet made\"]\n    },\n    {\n      \"year\": 1994,\n      \"claim\": \"Linked Cdc37 to both receptor-tyrosine-kinase signaling and cell-cycle kinase regulation, hinting that kinases are the common denominator of its function.\",\n      \"evidence\": \"Genetic screen and dominant enhancement of Dmcdc2 mutations in Drosophila\",\n      \"pmids\": [\"8020093\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanism of kinase regulation unknown\", \"Direct binding not demonstrated\", \"HSP90 link not yet established\"]\n    },\n    {\n      \"year\": 1996,\n      \"claim\": \"Identified CDC37 as a kinase-targeting subunit of HSP90 and defined CDK4 and v-Src as clients, recasting the gene as a kinase-specific HSP90 cochaperone.\",\n      \"evidence\": \"Co-IP, insect-cell coexpression, geldanamycin inhibition, half-life and fractionation assays (yeast and mammalian)\",\n      \"pmids\": [\"8666233\", \"9150368\", \"8885235\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Domain architecture undefined\", \"Structural basis of HSP90 binding unknown\", \"Whether activity is HSP90-dependent or autonomous unresolved\"]\n    },\n    {\n      \"year\": 1997,\n      \"claim\": \"Demonstrated that CDC37 has autonomous chaperone activity and client specificity distinct from HSP90, and extended its role to spindle pole body duplication via Mps1.\",\n      \"evidence\": \"In vitro refolding assays, genetic complementation, multicopy suppressor screen and kinase activity assays\",\n      \"pmids\": [\"9242486\", \"9060463\", \"9132011\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural basis of autonomous chaperone activity unknown\", \"How client specificity is encoded unresolved\"]\n    },\n    {\n      \"year\": 1999,\n      \"claim\": \"Showed CDC37 is the primary determinant of HSP90 recruitment to clients (Raf-1, Ste11, ZAP70), establishing a defined ternary-complex requirement for kinase activity.\",\n      \"evidence\": \"Baculovirus coexpression, dominant-negative mutants, geldanamycin, co-IP and signaling assays\",\n      \"pmids\": [\"10022854\", \"10664467\", \"10574909\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Order of complex assembly unclear\", \"Structural geometry of ternary complex unknown\"]\n    },\n    {\n      \"year\": 2001,\n      \"claim\": \"Defined a two-domain architecture in which the CDC37 N-terminus binds nascent kinases cotranslationally while the C-terminal region binds HSP90, and showed HSP90 nucleotide state gates CDC37's kinase-binding activity.\",\n      \"evidence\": \"Reticulocyte-lysate translation, truncation domain mapping, geldanamycin, kinase activity assay (HRI)\",\n      \"pmids\": [\"11036079\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Precise domain boundaries not yet mapped\", \"Atomic structure of either interface absent\"]\n    },\n    {\n      \"year\": 2002,\n      \"claim\": \"Established the biochemical mechanism of HSP90 regulation (ATPase suppression, dimeric binding) and broadened the client repertoire to Akt, IKK, LKB1, Aurora B and a Hsp90-independent viral RT, plus a CK2-Cdc37 feedback loop.\",\n      \"evidence\": \"ATPase assays, analytical ultracentrifugation, co-IP, gel filtration, purified-protein binding, site-directed phosphomutants\",\n      \"pmids\": [\"11916974\", \"11864612\", \"12176997\", \"12489981\", \"12374737\", \"12435747\", \"11986322\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural basis of ATPase suppression not yet visualized\", \"How phosphorylation controls binding mechanistically unknown\"]\n    },\n    {\n      \"year\": 2003,\n      \"claim\": \"Revealed Hsp90-independent client maturation (Spc1) and mapped client-determining motifs, refining how CDC37 selectively engages kinases.\",\n      \"evidence\": \"Genetic screens, co-IP, kinase and stress-signaling assays (fission yeast)\",\n      \"pmids\": [\"12861001\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Generality of HSP90-independent function unclear\", \"Structural determinant of client selectivity not defined\"]\n    },\n    {\n      \"year\": 2004,\n      \"claim\": \"Solved the crystal structure of the HSP90 N-domain/CDC37 core complex, defining at atomic resolution how CDC37 inserts an arginine into the ATP pocket and fixes the lid open to arrest the ATPase cycle, and delineated CDC37's three-domain organization and kinase N-lobe recognition.\",\n      \"evidence\": \"X-ray crystallography, SAXS, limited proteolysis/MS domain mapping, scanning mutagenesis, ATPase and binding assays, CK2 Ser13 phosphorylation mapping\",\n      \"pmids\": [\"14718169\", \"14580204\", \"15258137\", \"15082798\", \"15223329\", \"14742721\", \"12437126\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structure of full kinase-bound ternary complex still absent\", \"Conformational state of trapped client not visualized\"]\n    },\n    {\n      \"year\": 2006,\n      \"claim\": \"Provided the first 3D view of the full HSP90-CDC37-CDK4 ternary complex and identified the kinase glycine-rich loop as a CDC37 recognition element, connecting client engagement to the ATPase cycle.\",\n      \"evidence\": \"Single-particle electron microscopy, phage display, LC-MS/MS, chimeric-kinase mutagenesis and co-IP\",\n      \"pmids\": [\"16949366\", \"16611982\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Resolution insufficient to resolve client unfolding\", \"Atomic contacts within the complex unresolved\"]\n    },\n    {\n      \"year\": 2008,\n      \"claim\": \"Defined the regulatory phosphatase arm of the cycle, showing PP5/Ppt1 dephosphorylates pSer13-CDC37 specifically within the ternary HSP90 complex to control client activation and release, and crystallized the CDC37 middle domain identifying Leu-205 for HSP90 binding.\",\n      \"evidence\": \"Phosphospecific antibodies, in vitro phosphatase assays, genetic knockdown, crystallography, NMR, peptide-array and mutagenesis (multiple clients including PKC)\",\n      \"pmids\": [\"18922470\", \"19073599\", \"19091746\", \"19858214\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Coupling between dephosphorylation and physical release not structurally resolved\", \"Nucleotide-state preference and inhibitor mechanism only biochemically defined\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Mapped tyrosine-phosphorylation events on CDC37 and HSP90 that impose directionality on the chaperone cycle, and documented a kinase-independent function in which CDC37 alone can drive HSP90 dissociation and client nuclear translocation.\",\n      \"evidence\": \"Site-directed phosphotyrosine mutagenesis, co-IP, ATPase assays, TAP, nuclear translocation and reporter assays (ERK5)\",\n      \"pmids\": [\"22727666\", \"23428871\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Kinases responsible for tyrosine phosphorylation in vivo not fully defined\", \"Generality of kinase-independent translocation role unclear\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Established that CDC37 directly antagonizes client ATP binding and that ATP-competitive kinase inhibitors compete with CDC37 for the kinase N-lobe, providing a mechanistic rationale for inhibitor-induced client degradation in cancer; also showed CDC37 can stabilize clients with greatly reduced direct HSP90 binding.\",\n      \"evidence\": \"In vitro ATP-binding/competition assays, co-IP, inhibitor treatment, client degradation assays, HSP90-binding-deficient CDC37 mutants\",\n      \"pmids\": [\"23502424\", \"24292678\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How CDC37 stabilizes clients without direct HSP90 binding mechanistically unresolved\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Cryo-EM of the HSP90-CDC37-CDK4 complex revealed the client kinase N-lobe fully unfolded and trapped, with CDC37 mimicking the N-lobe and wedging between lobes, and defined CDC37 as a scanning factor that sorts clients by challenging their conformational stability.\",\n      \"evidence\": \"Cryo-EM (3.9 Å), NMR, hydrogen-deuterium exchange, client vs non-client binding assays\",\n      \"pmids\": [\"27339980\", \"27105117\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Snapshot of a single state; dynamics of loading and release not captured\", \"Generality across diverse kinase folds not fully established\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Full-length cryo-EM structures of RAF1- and BRAFV600E-containing HSP90-CDC37 complexes (the latter with PP5) defined the structural basis of RAF-family discrimination and revealed PP5 activation on the complex performing a comprehensive 'factory reset' dephosphorylation prior to client release.\",\n      \"evidence\": \"Cryo-EM of full-length complexes, proteomic phosphatase-activity analysis, co-IP\",\n      \"pmids\": [\"36055235\", \"36446791\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Kinetics of the full load-release cycle not resolved\", \"How diverse non-RAF clients are accommodated structurally unknown\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How CDC37's HSP90-independent chaperone activity operates mechanistically, and how a single cochaperone is tuned to handle the full diversity of its kinase and non-kinase clients, remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Structural basis of autonomous (HSP90-free) chaperone function undefined\", \"Determinants distinguishing client from non-client across the kinome not exhaustively mapped\", \"In vivo regulation of phospho-switches by upstream kinases incompletely characterized\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0044183\", \"supporting_discovery_ids\": [7, 25, 39, 55, 54]},\n      {\"term_id\": \"GO:0140096\", \"supporting_discovery_ids\": [4, 30, 31, 36]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [28, 22, 50, 42]},\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [11, 10, 17]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [9]},\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [60]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-392499\", \"supporting_discovery_ids\": [4, 39, 54, 55]},\n      {\"term_id\": \"R-HSA-1640170\", \"supporting_discovery_ids\": [0, 2, 4, 56]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [11, 21, 34, 45]},\n      {\"term_id\": \"R-HSA-9612973\", \"supporting_discovery_ids\": [46, 49]},\n      {\"term_id\": \"R-HSA-5357801\", \"supporting_discovery_ids\": [53]},\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [21, 34, 53]}\n    ],\n    \"complexes\": [\n      \"HSP90-CDC37 cochaperone complex\",\n      \"IKK complex\"\n    ],\n    \"partners\": [\n      \"HSP90\",\n      \"CDK4\",\n      \"CDK6\",\n      \"RAF1\",\n      \"AKT\",\n      \"PP5\",\n      \"STI1\",\n      \"CSNK2 (CK2)\"\n    ],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"tie","faith_supported":9,"faith_total":9,"faith_pct":100.0}}