CCT8 encodes the theta subunit of the cytosolic chaperonin-containing T-complex (CCT/TRiC). CCT/TRiC is an ATP-dependent hetero-oligomeric chaperonin formed from eight related subunits in each ring. The assembled complex folds actin, tubulin, and other cytosolic proteins.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0006457 protein folding | IBA GO_REF:0000033 | ACCEPT | Summary: CCT8 is a CCT/TRiC subunit and supports the protein-folding activity of the assembled chaperonin. Reason: Yeast CCT catalyzes actin folding, and PTHR11353 places CCT8 in the conserved chaperonin family. Supporting Evidence: PMID:16762366 Yeast CCT catalyses the folding of yeast ACT1p and human beta-actin with nearly identical rate constants and yields. file:interpro/panther/PTHR11353/PTHR11353-metadata.yaml PANTHER PTHR11353 classifies CCT8 in the chaperonin family. file:yeast/CCT8/CCT8-deep-research-falcon.md Falcon synthesis supports CCT8 as the CCT/TRiC theta subunit with conserved ATP-dependent chaperonin function. |
| GO:0005832 chaperonin-containing T-complex | IBA GO_REF:0000033 | ACCEPT | Summary: CCT8 is an integral component of the chaperonin-containing T-complex. Reason: The CCT complex is built from Cct1p-Cct8p subunits; CCT8 is the theta subunit of that complex. Supporting Evidence: PMID:15704212 Eukaryotic chaperonins, the Cct complexes, are assembled into two rings, each of which is composed of a stoichiometric array of eight different subunits, which are denoted Cct1p-Cct8p. |
| GO:0051082 unfolded protein binding | IBA GO_REF:0000033 | MODIFY | Summary: GO:0051082 is formally obsolete; Cct8 contributes to the CCT/TRiC complex's ATP-dependent protein-folding chaperone activity. Reason: GO:0051082 "unfolded protein binding" is obsolete with GO:0044183 protein folding chaperone and GO:0140309 unfolded protein holdase activity as consider terms. For Cct8, the evidence supports the GO:0140662 ATP-dependent protein folding chaperone activity of the CCT/TRiC complex; because Cct8 is one subunit of that complex, any final GOA replacement with GO:0140662 should use the contributes_to qualifier. This obsolete 2020 IBA is expected to lapse unless PAINT reasserts a molecular-function IBD; GO:0140662 is the appropriate non-obsolete replacement only if GOA retains a CCT8 molecular-function row derived from this source. Propagation Review Root cause: SOURCE STALE OR MISSING Failure modes: SOURCE EVIDENCE WEAK Sources checked: PANTHER:PTN004253040 · PAINT chaperonin node SOURCE STALE OR MISSING The current PTHR11353 PAINT record retains this node for conserved CCT/TRiC protein-folding biology, but it no longer carries obsolete GO:0051082 as a molecular-function IBD. Proposed replacements: ATP-dependent protein folding chaperone |
| GO:0000166 nucleotide binding | IEA GO_REF:0000043 | ACCEPT | Summary: Nucleotide binding is consistent with the conserved CCT chaperonin ATPase fold. Reason: The CCT family uses ATP binding and hydrolysis during substrate folding, so the keyword-derived term is retained as a valid molecular feature. |
| GO:0005524 ATP binding | IEA GO_REF:0000120 | ACCEPT | Summary: ATP binding is consistent with the ATP-dependent CCT/TRiC mechanism. Reason: CCT is an ATP-dependent protein-folding machine and CCT8 is a subunit of that complex. Supporting Evidence: PMID:16762366 The eukaryotic cytosolic chaperonin CCT is an essential ATP-dependent protein folding machine. |
| GO:0005737 cytoplasm | IEA GO_REF:0000044 | ACCEPT | Summary: CCT8 functions in the cytosolic CCT/TRiC chaperonin. Reason: CCT/TRiC folds cytosolic substrates such as actin and tubulin, and UniProt places CCT8 in the cytoplasm. |
| GO:0005832 chaperonin-containing T-complex | IEA GO_REF:0000117 | ACCEPT | Summary: ARBA annotation to the CCT complex is consistent with CCT8 subunit identity. Reason: The complex term is supported by the known Cct1p-Cct8p composition of CCT/TRiC. |
| GO:0006457 protein folding | IEA GO_REF:0000120 | ACCEPT | Summary: Protein folding is the core process mediated by CCT/TRiC. Reason: This broad BP term is retained because CCT8 contributes to the assembled CCT complex that catalyzes substrate folding. |
| GO:0016887 ATP hydrolysis activity | IEA GO_REF:0000002 | ACCEPT | Summary: ATP hydrolysis activity is consistent with CCT/TRiC chaperonin mechanism. Reason: The InterPro/PANTHER chaperonin family supports the conserved ATPase fold used during CCT-mediated substrate folding. |
| GO:0051082 unfolded protein binding | IEA GO_REF:0000120 | MODIFY | Summary: InterPro2GO still emits obsolete GO:0051082; the CCT/TRiC complex-level replacement is ATP-dependent protein folding chaperone activity. Reason: GO:0051082 "unfolded protein binding" is obsolete with GO:0044183 protein folding chaperone and GO:0140309 unfolded protein holdase activity as consider terms. For Cct8, the evidence supports the GO:0140662 ATP-dependent protein folding chaperone activity of the CCT/TRiC complex; because Cct8 is one subunit of that complex, any final GOA replacement with GO:0140662 should use the contributes_to qualifier. Proposed replacements: ATP-dependent protein folding chaperone |
| GO:0140662 ATP-dependent protein folding chaperone | IEA GO_REF:0000002 | ACCEPT | Summary: ATP-dependent protein folding chaperone is the most informative MF annotation for CCT8-containing CCT/TRiC. Reason: CCT/TRiC is an ATP-dependent folding machine, and CCT8 is a core subunit of that complex. Supporting Evidence: PMID:16762366 The eukaryotic cytosolic chaperonin CCT is an essential ATP-dependent protein folding machine. |
| GO:0005515 protein binding | IPI PMID:11805837 Systematic identification of protein complexes in Saccharomy... | REMOVE | Summary: The large-scale mass-spectrometry study supports CCT/TRiC context but not a distinct Cct8 protein-binding function. Reason: This large-scale mass-spectrometry study is useful evidence for CCT/TRiC complex membership, but it does not define a distinct generic protein-binding function beyond the established chaperonin activity. |
| GO:0005515 protein binding | IPI PMID:16554755 Global landscape of protein complexes in the yeast Saccharom... | REMOVE | Summary: The affinity-purification complex map supports CCT membership but not a standalone generic binding activity. Reason: This affinity-purification complex map supports CCT complex membership, but the specific curated functions are CCT/TRiC membership and ATP-dependent chaperonin-mediated folding rather than generic protein binding. |
| GO:0005515 protein binding | IPI PMID:19536198 An atlas of chaperone-protein interactions in Saccharomyces ... | REMOVE | Summary: The TAP-tag chaperone atlas supports CCT/TRiC contacts but GO:0005515 is not an informative Cct8 molecular-function assertion. Reason: PMID:19536198 reports broad TAP-tag chaperone interactions that are often indirect; the more precise function is CCT/TRiC chaperonin activity. Supporting Evidence: PMID:19536198 The interactions presented are indirect TAP-tag based interactions and not direct binary interactions. |
| GO:0005515 protein binding | IPI PMID:21734642 Combinatorial depletion analysis to assemble the network arc... | REMOVE | Summary: The SAGA/ADA perturbation network is peripheral to core CCT8 biology and does not define a specific Cct8 binding activity. Reason: This network analysis of SAGA and ADA perturbations is peripheral to CCT8's core chaperonin role and does not define a specific CCT8 binding activity; retaining only the CCT/TRiC chaperone annotations is more informative. |
| GO:0006457 protein folding | IDA PMID:16762366 Quantitative actin folding reactions using yeast CCT purifie... | ACCEPT | Summary: Direct biochemical evidence supports CCT-mediated protein folding. Reason: Purified yeast CCT folds actin in vitro; CCT8 contributes as a core subunit of that complex. Supporting Evidence: PMID:16762366 Yeast CCT catalyses the folding of yeast ACT1p and human beta-actin with nearly identical rate constants and yields. |
| GO:0005737 cytoplasm | HDA PMID:11914276 Subcellular localization of the yeast proteome. | ACCEPT | Summary: HDA localization to cytoplasm is consistent with the cytosolic CCT/TRiC complex. Reason: CCT/TRiC acts on cytosolic substrates and UniProt describes CCT8 as cytoplasmic. |
| GO:0005832 chaperonin-containing T-complex | IPI PMID:15704212 Physiological effects of unassembled chaperonin Cct subunits... | ACCEPT | Summary: Interaction evidence supports CCT8 membership in CCT/TRiC. Reason: The CCT complex is composed of Cct1p-Cct8p, and CCT8 is the theta subunit. |
| GO:0005832 chaperonin-containing T-complex | IDA PMID:16762366 Quantitative actin folding reactions using yeast CCT purifie... | ACCEPT | Summary: Direct purification of yeast CCT supports this cellular component annotation. Reason: The IDA evidence derives from purified yeast CCT, so the assembled complex term is accurate. |
| GO:0051082 unfolded protein binding | IDA PMID:16762366 Quantitative actin folding reactions using yeast CCT purifie... | MODIFY | Summary: The CCT3-tagged yeast complex supports CCT/TRiC foldase function, not a standalone obsolete unfolded-protein-binding activity for Cct8. Reason: GO:0051082 "unfolded protein binding" is obsolete with GO:0044183 protein folding chaperone and GO:0140309 unfolded protein holdase activity as consider terms. For Cct8, the actin-folding evidence supports the GO:0140662 ATP-dependent protein folding chaperone activity of the CCT/TRiC complex; because Cct8 is one subunit of that complex, any final GOA replacement with GO:0140662 should use the contributes_to qualifier. Proposed replacements: ATP-dependent protein folding chaperone |
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Download this section (compressed HTML)Q: Does the CCT8/theta subunit contribute any substrate-specific contacts that differ from other yeast CCT subunits?
Experiment: Map substrate contacts in yeast CCT/TRiC by crosslinking folded substrates under CCT8-specific perturbation and comparing with other CCT subunits.
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Download this section (compressed HTML)Subunit of the cytosolic chaperonin Cct ring complex; related to Tcp1p, required for the assembly of actin and tubulins in vivo
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