CCT6

UniProt ID: P39079
Organism: Saccharomyces cerevisiae
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. Its core GO function is therefore the TRiC/CCT chaperonin role, with unassembled-subunit phenotypes treated as contextual rather than separate core annotations.

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: unfolded protein binding reflects substrate engagement by TRiC/CCT, but it is less informative than the ATP-dependent folding chaperone function of the complex.
Reason: Replace generic substrate-binding language with the specific chaperonin activity supported by yeast CCT actin-folding assays and domain evidence.
GO:0000166 nucleotide binding
IEA
GO_REF:0000043 		MARK AS OVER ANNOTATED
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: Generic nucleotide binding does not add useful functional information beyond the more specific ATP-related chaperonin annotations already present.
GO:0005524 ATP binding
IEA
GO_REF:0000120 		KEEP AS NON CORE
Summary: CCT6 contains a conserved chaperonin ATP-binding site, but ATP binding alone is a domain property rather than the core biological function.
Reason: Keep as a valid supporting molecular property of the CCT ATPase cycle, while treating ATP hydrolysis and complex-level protein folding as the core function.
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: unfolded protein binding reflects substrate engagement by TRiC/CCT, but it is less informative than the ATP-dependent folding chaperone function of the complex.
Reason: Replace generic substrate-binding language with the specific chaperonin activity supported by yeast CCT actin-folding assays and domain evidence.
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... 		MARK AS OVER ANNOTATED
Summary: protein binding is too generic for a CCT subunit and does not describe the chaperonin mechanism or substrate class.
Reason: Physical-interaction datasets are useful evidence context, but generic protein binding should not stand as a functional annotation when the specific TRiC/CCT chaperonin role is known.
GO:0005515 protein binding
IPI
PMID:19536198
An atlas of chaperone-protein interactions in Saccharomyces ... 		MARK AS OVER ANNOTATED
Summary: protein binding is too generic for a CCT subunit and does not describe the chaperonin mechanism or substrate class.
Reason: Physical-interaction datasets are useful evidence context, but generic protein binding should not stand as a functional annotation when the specific TRiC/CCT chaperonin role is known.
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 ... 		MARK AS OVER ANNOTATED
Summary: protein binding is too generic for a CCT subunit and does not describe the chaperonin mechanism or substrate class.
Reason: Physical-interaction datasets are useful evidence context, but generic protein binding should not stand as a functional annotation when the specific TRiC/CCT chaperonin role is known.
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: unfolded protein binding reflects substrate engagement by TRiC/CCT, but it is less informative than the ATP-dependent folding chaperone function of the complex.
Reason: Replace generic substrate-binding language with the specific chaperonin activity supported by yeast CCT actin-folding assays and domain 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

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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