CCT6

UniProt ID: P39079
Organism: Saccharomyces cerevisiae S288C
Review Status: COMPLETE
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Gene Description

CCT6 encodes the zeta subunit of the cytosolic group II chaperonin TRiC/CCT. Cct6 contributes to the ATP-driven chaperonin chamber that folds actin, tubulin, and other cytosolic clients, and yeast genetics also shows that excess unassembled Cct6 can suppress diverse conditional phenotypes in an ATP-motif-dependent state.

Existing Annotations Review

GO Term Evidence Action Reason
GO:0006457 protein folding
IBA
GO_REF:0000033 		ACCEPT
Summary: CCT6 participates in protein folding as an obligate subunit of TRiC/CCT, the cytosolic chaperonin that folds actin, tubulin, and other clients.
Reason: Protein folding is the correct biological-process context for the chaperonin complex, supported by direct yeast CCT actin-folding assays and PANTHER/InterPro family evidence.
Supporting Evidence:
file:yeast/CCT6/CCT6-deep-research-falcon.md
a structural/ATPase subunit of the TRiC/CCT chaperonin
GO:0005832 chaperonin-containing T-complex
IBA
GO_REF:0000033 		ACCEPT
Summary: CCT6 is a named subunit of the chaperonin-containing T-complex.
Reason: Complex membership is central to the gene product function and is supported by yeast CCT complex literature and family evidence.
GO:0051082 unfolded protein binding
IBA
GO_REF:0000033 		MODIFY
Summary: GO:0051082 is formally obsolete; Cct6 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Reason: GO:0051082 "unfolded protein binding" is obsolete with GO:0044183 protein folding chaperone and GO:0140309 unfolded protein holdase activity as consider terms.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 Cct6, the evidence supports the GO:0140662 ATP-dependent protein folding chaperone activity of the CCT/TRiC complex; because Cct6 is one subunit of that complex, any final GOA replacement with GO:0140662 should use the contributes_to qualifier.
Propagation Review
Root cause: TERM SCOPING PROBLEM
Failure modes: GRANULARITY MISMATCH
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.
SGD:S000002596 · CCT6 self-donor IDA SUPPORTS TRANSFER
CCT6 appears in its own WITH/FROM because its PMID:16762366 IDA was one of the yeast CCT subunit evidences used to place the 2020 GO:0051082 IBD; this supports inherited CCT/TRiC foldase biology even though the obsolete binding term needs a contributes_to chaperone replacement.
GO:0000166 nucleotide binding
IEA
GO_REF:0000043 		MODIFY
Summary: nucleotide binding is a true but overly broad family/keyword annotation for CCT6; ATP binding, ATP hydrolysis, and ATP-dependent chaperone annotations capture the specific chemistry.
Reason: The retired UniProt keyword row captured the nucleotide-binding fold at overly generic scope; the current InterPro2GO rows split the assertion into ATP binding and ATP hydrolysis, which better match the CCT chaperonin ATPase cycle.
GO:0005524 ATP binding
IEA
GO_REF:0000120 		ACCEPT
Summary: CCT6 contains a conserved TCP-1/CCT ATP-binding site that directly feeds the chaperonin ATPase cycle.
Reason: Retain as a direct subunit molecular function supported by conserved CCT ATPase-domain biology and inherited by the current InterPro ATP-binding row.
GO:0005737 cytoplasm
IEA
GO_REF:0000044 		ACCEPT
Summary: CCT6 functions as part of the cytosolic TRiC/CCT chaperonin.
Reason: Cytoplasm is the established location of the CCT/TRiC folding machine.
GO:0005832 chaperonin-containing T-complex
IEA
GO_REF:0000117 		ACCEPT
Summary: CCT6 is a named subunit of the chaperonin-containing T-complex.
Reason: Complex membership is central to the gene product function and is supported by yeast CCT complex literature and family evidence.
GO:0006457 protein folding
IEA
GO_REF:0000120 		ACCEPT
Summary: CCT6 participates in protein folding as an obligate subunit of TRiC/CCT, the cytosolic chaperonin that folds actin, tubulin, and other clients.
Reason: Protein folding is the correct biological-process context for the chaperonin complex, supported by direct yeast CCT actin-folding assays and PANTHER/InterPro family evidence.
GO:0016887 ATP hydrolysis activity
IEA
GO_REF:0000002 		ACCEPT
Summary: CCT6 is a TCP-1/CCT chaperonin subunit with conserved ATPase machinery that powers TRiC/CCT conformational cycling.
Reason: ATP hydrolysis is a defensible subunit-level molecular function for CCT family members and is directly tied to the chaperonin folding cycle.
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 Cct6, the evidence supports the GO:0140662 ATP-dependent protein folding chaperone activity of the CCT/TRiC complex; because Cct6 is one subunit of that complex, any final GOA replacement with GO:0140662 should use the contributes_to qualifier.
GO:0140662 ATP-dependent protein folding chaperone
IEA
GO_REF:0000002 		ACCEPT
Summary: CCT6 is an obligate subunit of the ATP-dependent TRiC/CCT folding machine.
Reason: The term is appropriate as a complex-level chaperonin function; in the synthesized core function it is modeled as a contributed-to molecular function rather than a standalone activity of an isolated subunit.
Supporting Evidence:
PMID:16762366
The eukaryotic cytosolic chaperonin CCT is an essential ATP-dependent protein folding machine whose action is required for folding the cytoskeletal proteins actin and tubulin
GO:0005515 protein binding
IPI
PMID:16554755
Global landscape of protein complexes in the yeast Saccharom... 		REMOVE
Summary: The complex map is useful CCT/TRiC context but does not define a specific Cct6 binding activity.
Reason: This large-scale affinity-purification map is useful evidence for CCT/TRiC complex membership, but it does not define a specific molecular binding activity for Cct6 beyond the established chaperonin complex and ATP-dependent folding function.
GO:0005515 protein binding
IPI
PMID:19536198
An atlas of chaperone-protein interactions in Saccharomyces ... 		REMOVE
Summary: The CCT6-CCT4 TAP evidence supports chaperonin contacts but GO:0005515 is not an informative Cct6 molecular-function assertion.
Reason: The CCT4 interaction is useful physical-interaction context, but it does not define a specific replacement binding activity for this TRiC/CCT subunit; the generic protein-binding annotation should be removed in favor of Cct6's accepted chaperonin-complex and ATP-dependent folding activities.
Supporting Evidence:
PMID:19536198
It should be emphasized that the interactions presented are indirect TAP-tag based interactions and not direct binary interactions.
GO:0005515 protein binding
IPI
PMID:37968396
The social and structural architecture of the yeast protein ... 		REMOVE
Summary: The proteome-scale interactome helps recover CCT/TRiC connectivity but not a specific standalone protein-binding function for Cct6.
Reason: This proteome-scale interactome helps recover CCT/TRiC connectivity, but it does not establish a specific protein-binding molecular function beyond Cct6's core ATP-dependent chaperonin activity.
GO:0006457 protein folding
IDA
PMID:16762366
Quantitative actin folding reactions using yeast CCT purifie... 		ACCEPT
Summary: CCT6 participates in protein folding as an obligate subunit of TRiC/CCT, the cytosolic chaperonin that folds actin, tubulin, and other clients.
Reason: Protein folding is the correct biological-process context for the chaperonin complex, supported by direct yeast CCT actin-folding assays and PANTHER/InterPro family evidence.
Supporting Evidence:
PMID:16762366
The eukaryotic cytosolic chaperonin CCT is an essential ATP-dependent protein folding machine whose action is required for folding the cytoskeletal proteins actin and tubulin
GO:0005832 chaperonin-containing T-complex
IDA
PMID:16762366
Quantitative actin folding reactions using yeast CCT purifie... 		ACCEPT
Summary: CCT6 is a named subunit of the chaperonin-containing T-complex.
Reason: Complex membership is central to the gene product function and is supported by yeast CCT complex literature and family evidence.
Supporting Evidence:
PMID:16762366
The eukaryotic cytosolic chaperonin CCT is an essential ATP-dependent protein folding machine whose action is required for folding the cytoskeletal proteins actin and tubulin
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 Cct6.
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 Cct6, the actin-folding evidence supports the GO:0140662 ATP-dependent protein folding chaperone activity of the CCT/TRiC complex; because Cct6 is one subunit of that complex, any final GOA replacement with GO:0140662 should use the contributes_to qualifier.
Supporting Evidence:
PMID:16762366
The eukaryotic cytosolic chaperonin CCT is an essential ATP-dependent protein folding machine whose action is required for folding the cytoskeletal proteins actin and tubulin
GO:0005524 ATP binding
IEA
GO_REF:0000002 		ACCEPT
Summary: CCT6 has the conserved TCP-1/CCT ATP-binding domains that feed the TRiC conformational cycle.
Reason: Retain as a direct subunit molecular function supported by conserved CCT ATPase-domain biology; the InterPro2GO row now emits this specific ATP-binding assertion for the same chaperonin domains that also support Cct6 ATP hydrolysis.
GO:0005832 chaperonin-containing T-complex
IPI
PMID:21701561
The crystal structure of yeast CCT reveals intrinsic asymmet... 		ACCEPT
Summary: The yeast CCT crystal structure supports Cct6 as a constituent of the chaperonin-containing T-complex.
Reason: ComplexPortal's 2025 row adds the 2011 yeast CCT crystal structure as direct complex-membership evidence. The structure is of the asymmetric yeast CCT/TRiC complex, and Cct6 is the zeta subunit of that complex.
Supporting Evidence:
PMID:21701561
We have solved the crystal structure of yeast CCT in complex with actin

Core Functions

CCT6 is the zeta subunit of the cytosolic TRiC/CCT chaperonin. The subunit contributes ATPase and substrate-contact surfaces to the hetero-oligomeric double-ring complex, whose ATP-dependent conformational cycle folds actin, tubulin, and other cytosolic client proteins. The synthesized function is modeled as subunit ATP hydrolysis contributing to the complex-level ATP-dependent protein folding chaperone activity.

Molecular Function:
ATP hydrolysis activity
Directly Involved In:
protein folding
Cellular Locations:
cytoplasm
In Complex:
chaperonin-containing T-complex
Supporting Evidence:
  • PMID:16762366
    The eukaryotic cytosolic chaperonin CCT is an essential ATP-dependent protein folding machine whose action is required for folding the cytoskeletal proteins actin and tubulin
  • 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

References

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Suggested Questions for Experts

Q: Which physiological effects of CCT6 overexpression are caused by unassembled Cct6p versus altered flux through assembled TRiC/CCT?

Suggested Experiments

Experiment: Measure assembled TRiC/CCT, free Cct6p, and candidate client interactions across CCT6 overexpression and ATP-motif mutant backgrounds that differ in suppression but retain viability.

Hypothesis: Unassembled Cct6p suppresses selected conditional phenotypes by sequestering or buffering client proteins independently of increasing assembled TRiC/CCT.

Type: native complex profiling with affinity purification and genetic suppression assays

Deep Research

Falcon

(CCT6-deep-research-falcon.md)

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SGD

(CCT6-deep-research-sgd.md)
SGD gene description for CCT6 (yeast) SGD

SGD gene description for CCT6 (yeast)

Subunit of the cytosolic chaperonin Cct ring complex; related to Tcp1p, essential protein that is required for the assembly of actin and tubulins in vivo; contains an ATP-binding motif

📚 Additional Documentation

Notes

(CCT6-notes.md)

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📄 View Raw YAML

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