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:
Cellular Locations:
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

Gene Ontology annotation through association of InterPro records with GO terms
Annotation inferences using phylogenetic trees
Gene Ontology annotation based on UniProtKB/Swiss-Prot keyword mapping
Gene Ontology annotation based on UniProtKB/Swiss-Prot Subcellular Location vocabulary mapping, accompanied by conservative changes to GO terms applied by UniProt
Electronic Gene Ontology annotations created by ARBA machine learning models
Combined Automated Annotation using Multiple IEA Methods
Global landscape of protein complexes in the yeast Saccharomyces cerevisiae.
Quantitative actin folding reactions using yeast CCT purified via an internal tag in the CCT3/gamma subunit.
  • Purified yeast CCT, tagged through CCT3, catalyzes ATP-dependent actin folding; this supports protein-folding and chaperonin activity annotations for CCT6 as a TRiC/CCT subunit.
    "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"
Physiological effects of unassembled chaperonin Cct subunits in the yeast Saccharomyces cerevisiae.
  • Yeast CCT is a double-ring complex with a stoichiometric set of eight distinct Cct subunits.
    "Eukaryotic chaperonins, the Cct complexes, are assembled into two rings, each of which is composed of a stoichiometric array of eight different subunits"
An atlas of chaperone-protein interactions in Saccharomyces cerevisiae: implications to protein folding pathways in the cell.
  • The chaperone interactome study is useful context for CCT contacts but reports indirect TAP-tag interactions rather than a specific molecular activity.
    "It should be emphasized that the interactions presented are indirect TAP-tag based interactions and not direct binary interactions."
The social and structural architecture of the yeast protein interactome.
file:yeast/CCT6/CCT6-deep-research-falcon.md
Falcon deep research report for CCT6
  • The Falcon report was reviewed and synthesized into the CCT6 curation, including core-function framing, family/PANTHER context, and evidence limitations.

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

📚 Additional Documentation

Deep Research Falcon

(CCT6-deep-research-falcon.md)

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gene_id: CCT6
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uniprot_accession: P39079
protein_description: 'RecName: Full=T-complex protein 1 subunit zeta; Short=TCP-1-zeta;
AltName: Full=CCT-zeta;'
gene_info: Name=CCT6; Synonyms=TCP20, TCP6; OrderedLocusNames=YDR188W; ORFNames=YD9395.21;
organism_full: Saccharomyces cerevisiae (strain ATCC 204508 / S288c) (Baker's yeast).
protein_family: Belongs to the TCP-1 chaperonin family. .
protein_domains: Chap_CCT_zeta. (IPR012722); Chaperone_TCP-1. (IPR017998); Chaperonin_TCP-1_CS.
(IPR002194); Cpn60/GroEL/TCP-1. (IPR002423); GroEL-like_apical_dom_sf. (IPR027409)
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Question

Gene Research for Functional Annotation

⚠️ CRITICAL: Gene/Protein Identification Context

BEFORE YOU BEGIN RESEARCH: You MUST verify you are researching the CORRECT gene/protein. Gene symbols can be ambiguous, especially for less well-characterized genes from non-model organisms.

Target Gene/Protein Identity (from UniProt):

  • UniProt Accession: P39079
  • Protein Description: RecName: Full=T-complex protein 1 subunit zeta; Short=TCP-1-zeta; AltName: Full=CCT-zeta;
  • Gene Information: Name=CCT6; Synonyms=TCP20, TCP6; OrderedLocusNames=YDR188W; ORFNames=YD9395.21;
  • Organism (full): Saccharomyces cerevisiae (strain ATCC 204508 / S288c) (Baker's yeast).
  • Protein Family: Belongs to the TCP-1 chaperonin family. .
  • Key Domains: Chap_CCT_zeta. (IPR012722); Chaperone_TCP-1. (IPR017998); Chaperonin_TCP-1_CS. (IPR002194); Cpn60/GroEL/TCP-1. (IPR002423); GroEL-like_apical_dom_sf. (IPR027409)

MANDATORY VERIFICATION STEPS:

  1. Check if the gene symbol "CCT6" matches the protein description above
  2. Verify the organism is correct: Saccharomyces cerevisiae (strain ATCC 204508 / S288c) (Baker's yeast).
  3. Check if protein family/domains align with what you find in literature
  4. If you find literature for a DIFFERENT gene with the same or similar symbol, STOP

If Gene Symbol is Ambiguous or You Cannot Find Relevant Literature:

DO NOT PROCEED WITH RESEARCH ON A DIFFERENT GENE. Instead:
- State clearly: "The gene symbol 'CCT6' is ambiguous or literature is limited for this specific protein"
- Explain what you found (e.g., "Found extensive literature on a different gene with the same symbol in a different organism")
- Describe the protein based ONLY on the UniProt information provided above
- Suggest that the protein function can be inferred from domain/family information

Research Target:

Please provide a comprehensive research report on the gene CCT6 (gene ID: CCT6, UniProt: P39079) in yeast.

The research report should be a detailed narrative explaining the function, biological processes, and localization of the gene product. Citations should be given for all claims.

You should prioritize authoritative reviews and primary scientific literature when conducting research. You can supplement
this with annotations you find in gene/protein databases, but these can be outdated or inaccurate.

We are specifically interested in the primary function of the gene - for enzymes, what reaction is catalyzed, and what is the substrate specificity? For transporters, what is the substrate? For structural proteins or adapters, what is the broader structural role? For signaling molecules, what is the role in the pathway.

We are interested in where in or outside the cell the gene product carries out its function.

We are also interested in the signaling or biochemical pathways in which the gene functions. We are less interested in broad pleiotropic effects, except where these elucidate the precise role.

Include evidence where possible. We are interested in both experimental evidence as well as inference from structure, evolution, or bioinformatic analysis. Precise studies should be prioritized over high-throughput, where available.

Output

Question: You are an expert researcher providing comprehensive, well-cited information.

Provide detailed information focusing on:
1. Key concepts and definitions with current understanding
2. Recent developments and latest research (prioritize 2023-2024 sources)
3. Current applications and real-world implementations
4. Expert opinions and analysis from authoritative sources
5. Relevant statistics and data from recent studies

Format as a comprehensive research report with proper citations. Include URLs and publication dates where available.
Always prioritize recent, authoritative sources and provide specific citations for all major claims.

Gene Research for Functional Annotation

⚠️ CRITICAL: Gene/Protein Identification Context

BEFORE YOU BEGIN RESEARCH: You MUST verify you are researching the CORRECT gene/protein. Gene symbols can be ambiguous, especially for less well-characterized genes from non-model organisms.

Target Gene/Protein Identity (from UniProt):

  • UniProt Accession: P39079
  • Protein Description: RecName: Full=T-complex protein 1 subunit zeta; Short=TCP-1-zeta; AltName: Full=CCT-zeta;
  • Gene Information: Name=CCT6; Synonyms=TCP20, TCP6; OrderedLocusNames=YDR188W; ORFNames=YD9395.21;
  • Organism (full): Saccharomyces cerevisiae (strain ATCC 204508 / S288c) (Baker's yeast).
  • Protein Family: Belongs to the TCP-1 chaperonin family. .
  • Key Domains: Chap_CCT_zeta. (IPR012722); Chaperone_TCP-1. (IPR017998); Chaperonin_TCP-1_CS. (IPR002194); Cpn60/GroEL/TCP-1. (IPR002423); GroEL-like_apical_dom_sf. (IPR027409)

MANDATORY VERIFICATION STEPS:

  1. Check if the gene symbol "CCT6" matches the protein description above
  2. Verify the organism is correct: Saccharomyces cerevisiae (strain ATCC 204508 / S288c) (Baker's yeast).
  3. Check if protein family/domains align with what you find in literature
  4. If you find literature for a DIFFERENT gene with the same or similar symbol, STOP

If Gene Symbol is Ambiguous or You Cannot Find Relevant Literature:

DO NOT PROCEED WITH RESEARCH ON A DIFFERENT GENE. Instead:
- State clearly: "The gene symbol 'CCT6' is ambiguous or literature is limited for this specific protein"
- Explain what you found (e.g., "Found extensive literature on a different gene with the same symbol in a different organism")
- Describe the protein based ONLY on the UniProt information provided above
- Suggest that the protein function can be inferred from domain/family information

Research Target:

Please provide a comprehensive research report on the gene CCT6 (gene ID: CCT6, UniProt: P39079) in yeast.

The research report should be a detailed narrative explaining the function, biological processes, and localization of the gene product. Citations should be given for all claims.

You should prioritize authoritative reviews and primary scientific literature when conducting research. You can supplement
this with annotations you find in gene/protein databases, but these can be outdated or inaccurate.

We are specifically interested in the primary function of the gene - for enzymes, what reaction is catalyzed, and what is the substrate specificity? For transporters, what is the substrate? For structural proteins or adapters, what is the broader structural role? For signaling molecules, what is the role in the pathway.

We are interested in where in or outside the cell the gene product carries out its function.

We are also interested in the signaling or biochemical pathways in which the gene functions. We are less interested in broad pleiotropic effects, except where these elucidate the precise role.

Include evidence where possible. We are interested in both experimental evidence as well as inference from structure, evolution, or bioinformatic analysis. Precise studies should be prioritized over high-throughput, where available.

Research report: CCT6 (YDR188W; UniProt P39079) in Saccharomyces cerevisiae (S288c)

Executive summary

CCT6 (YDR188W; UniProt P39079) encodes T-complex protein 1 subunit zeta (Cct6p; also called CCT-ζ), one of eight paralogous subunits that assemble into the essential cytosolic group II chaperonin TRiC/CCT. TRiC/CCT is a ~1 MDa ATP-dependent double-ring folding machine required for maturation of a specific subset of eukaryotic proteins—classically actin and tubulin—and is estimated to mediate folding of roughly ~10% of newly synthesized polypeptides in yeast. Yeast genetics further indicates that CCT6 is essential, and that excess/unassembled Cct6p (produced by overexpression) can suppress multiple conditional growth defects in otherwise unrelated pathways (TOR signaling, trafficking/vacuole/cell wall, ubiquitin ligase function), implying physiologically meaningful activity beyond (or in addition to) the assembled TRiC complex. Recent 2023–2024 studies refine TRiC allostery/ATPase kinetics, connect TRiC malfunction to stress-response pathways (e.g., cell-wall integrity MAPK signaling), and expand the functional landscape to include nuclear roles for TRiC in transcriptional homeostasis; however, these advances are mostly complex-level and not uniquely CCT6-subunit–specific. (grantham2020themolecularchaperone pages 1-2, dube2023saccharomycescerevisiaesurvival pages 1-4, kabir2005physiologicaleffectsof pages 1-2, kabir2005physiologicaleffectsof pages 2-4)

Evidence map (high-level)

Claim/Topic Key evidence (short) Organism/system Source (author year) Publication date URL/DOI Notes/caveats
Identity / disambiguation Yeast CCT6 / YDR188W / UniProt P39079 encodes T-complex protein 1 subunit zeta (Cct6p), one of the eight paralogous subunits of the eukaryotic cytosolic group II chaperonin TRiC/CCT; literature here refers to the yeast chaperonin subunit, not mammalian CCT6A/B paralogs (kabir2005physiologicaleffectsof pages 1-2, kabir2005physiologicaleffectsof pages 2-4) Saccharomyces cerevisiae Kabir et al. 2005 2005-02 https://doi.org/10.1002/yea.1210 Older but yeast-specific foundational annotation; important because CCT6 is ambiguous across organisms.
Complex membership TRiC/CCT is a ~1 MDa double-ring complex with two stacked octameric rings; each ring contains CCT1–CCT8 in fixed order, with CCT6 as one subunit (grantham2020themolecularchaperone pages 1-2, zang2018developmentofa pages 1-2) Yeast TRiC/CCT / eukaryotic TRiC Grantham 2020; Zang et al. 2018 2020-03; 2018-02 https://doi.org/10.3389/fgene.2020.00172 ; https://doi.org/10.1038/s41598-017-18962-y Complex-level function is better established than isolated Cct6p-specific biochemistry.
Essentiality All eight yeast CCT1–CCT8 genes are essential; disruption experiments showed each is required, including CCT6 (kabir2008overexpressedribosomalproteins pages 1-2, kabir2005physiologicaleffectsof pages 2-4) S. cerevisiae Kabir & Sherman 2008; Kabir et al. 2005 2008-12; 2005-02 https://doi.org/10.1111/j.1567-1364.2008.00425.x ; https://doi.org/10.1002/yea.1210 Essentiality is gene-level; not every subunit’s ATPase chemistry is equally essential.
Canonical substrates / primary function TRiC/CCT performs ATP-dependent folding of obligate cytosolic substrates, especially actin and tubulin; CCT is required for tubulin biogenesis and actin folding, providing the main functional context for CCT6 (grantham2020themolecularchaperone pages 1-2, kelly2020structuralandfunctional pages 18-23, willison2018thestructureand pages 1-2) Eukaryotic cytosol; yeast-focused review context Grantham 2020; Kelly 2020; Willison 2018 2020-03; 2020; 2018-10 https://doi.org/10.3389/fgene.2020.00172 ; n/a ; https://doi.org/10.1042/BCJ20170378 Evidence is strongest at complex level; direct yeast Cct6-substrate specificity remains less resolved than for the complex as a whole.
ATPase / hemisphere specialization CCT6 belongs to the low-ATP-affinity hemisphere (with CCT3/6/7/8); sequence divergence near the nucleotide pocket and structural analyses suggest lower nucleotide exchange, and P-loop alanine substitutions in low-affinity subunits had little growth effect relative to high-affinity subunits (kelly2020structuralandfunctionala pages 42-48, kelly2020structuralandfunctional pages 42-48) Yeast TRiC/CCT Kelly 2020 2020 n/a Strong structural/kinetic inference; thesis source, but evidence summarized from cryo-EM, nucleotide assays, and yeast mutational work.
CCT6-specific ATP-cycle nuance Cct6p is described as a low-affinity/low-turnover subunit; one source notes Cct6p and Cct8p remain ADP-bound and do not participate like high-affinity subunits, and a glycine-motif mutation analogous to ts mutations in other subunits did not impair growth when introduced in Cct6p (dube2021chaperoninpointmutation pages 1-4) S. cerevisiae CCT Dube & Kabir 2021 2021-05 https://doi.org/10.1007/s10529-021-03151-9 Useful subunit-specific nuance, but based on synthesis of prior work rather than a direct dedicated CCT6 biochemical paper.
Subunit position / structure Cryo-EM with internal eGFP labeling (YISEL) assigned CCT6 as an on-axis subunit (a5 / subunit 6) in yeast TRiC and helped define full subunit order; CCT6 contributes to the characteristic Z-shaped on-axis pair geometry (zang2018developmentofa pages 1-2, zang2018developmentofa media 20a150a9) Yeast TRiC/CCT Zang et al. 2018 2018-02 https://doi.org/10.1038/s41598-017-18962-y Structural assignment is direct and yeast-specific.
Inter-ring structural role Structural analyses indicate the N-terminus of CCT6 participates in inter-ring interactions/stacking during TRiC closure, supporting a role in conformational locking rather than being a dominant ATP-hydrolyzing driver (kelly2020structuralandfunctionala pages 42-48, kelly2020structuralandfunctional pages 42-48) Yeast TRiC/CCT Kelly 2020 2020 n/a Mechanistic inference from structures and comparative mutational studies.
Unassembled Cct6 suppressor activity Overexpression of CCT6 increases unassociated Cct6p, not total assembled CCT complex, and this excess subunit suppresses diverse conditional phenotypes (tor2-21, lst8-2, rsp5-9, [SIT4 SAP155]N) (kabir2005physiologicaleffectsof pages 1-2, kabir2005physiologicaleffectsof pages 2-4) S. cerevisiae genetics Kabir et al. 2005 2005-02 https://doi.org/10.1002/yea.1210 Important evidence that Cct6p may have physiologically relevant extra-complex activity or sequestration/competition effects.
Requirement for ATP-binding motif in suppressor function The cct6-24 mutant with GDGTT→AAAAA replacement in the conserved ATP-binding motif was unable to suppress those conditional traits, despite supporting growth, implying suppression depends on a specific functional state of unassembled Cct6p (kabir2005physiologicaleffectsof pages 1-2) S. cerevisiae Kabir et al. 2005 2005-02 https://doi.org/10.1002/yea.1210 Strong evidence for separable roles: viability of mutant allele vs loss of suppressor activity.
Genetic phenotypes / ts alleles Multiple temperature-sensitive cct6 alleles were reported (e.g., cct6-14, -18, -27, -74, -85, -93, -97), many with TBZ sensitivity and some with NaCl sensitivity, consistent with roles in microtubule/actin-related processes (kabir2008overexpressedribosomalproteins pages 1-2, kabir2008overexpressedribosomalproteins pages 2-3) S. cerevisiae Kabir & Sherman 2008 2008-12 https://doi.org/10.1111/j.1567-1364.2008.00425.x Phenotypes derive from legacy allele collections; not all were mechanistically dissected.
Multicopy suppressors of cct defects Kabir & Sherman isolated 22 multicopy suppressors of a cct4 ts allele; 14 encoded ribosomal proteins, and some suppressors also acted on certain cct6 mutants, suggesting overexpressed ribosomal proteins can weakly buffer defective chaperonins (kabir2008overexpressedribosomalproteins pages 1-2, kabir2008overexpressedribosomalproteins pages 2-3) S. cerevisiae Kabir & Sherman 2008 2008-12 https://doi.org/10.1111/j.1567-1364.2008.00425.x Indirectly informative for CCT6 buffering/genetic interaction space.
CCT6 vs CCT3 subunit-specific interactome effects A conserved ATP-site Glu→Asp mutation in CCT6 was compared with CCT3 in high-throughput microscopy; each mutant produced distinct proteome-level effects, and CCT3 showed stronger association with Q/N-rich proteins/P-body phenotypes than CCT6 (nadlerholly2012interactionsofsubunit pages 1-2) S. cerevisiae Nadler-Holly et al. 2012 2012-11 https://doi.org/10.1073/pnas.1209277109 Useful because it argues subunit specialization; CCT6 phenotype was milder/different than CCT3 for this substrate class.
Cytosolic localization / classical role TRiC/CCT is classically a cytosolic folding machine in yeast/eukaryotes, accounting for ~10% of new polypeptide maturation; this is the best-supported localization/function for Cct6p as part of the holo-complex (gvozdenov2024triccctchaperoningoverns pages 1-6, dube2023saccharomycescerevisiaesurvival pages 1-4) Yeast / eukaryotic cytosol Gvozdenov et al. 2024; Dube et al. 2023 2024-09-26; 2023-11 https://doi.org/10.1101/2024.09.26.615188 ; https://doi.org/10.1007/s42977-023-00192-1 Dube 2023 is about CCT7 mutant, but explicitly states yeast TRiC/CCT is cytosolic and folds ~10% of polypeptides.
Nuclear localization / emerging role Recent work shows TRiC/CCT is also present in the nucleus and can regulate RNA polymerase II activity and nascent RNA homeostasis; this extends likely functional context for all subunits including CCT6, though not yet CCT6-specific (gvozdenov2024triccctchaperoningoverns pages 1-6) S. cerevisiae Gvozdenov et al. 2024 2024-09-26 https://doi.org/10.1101/2024.09.26.615188 Preprint; compelling for nuclear TRiC, but not direct evidence that CCT6 alone mediates the effect.
Recent development: stress/pathway crosstalk A 2023 yeast study showed a cct7 folding-defective mutant is heat- and cell-wall-stress sensitive and is rescued by PKC1/SLT2, supporting crosstalk between CCT proteostasis and the cell wall integrity (CWI) MAPK pathway (dube2023saccharomycescerevisiaesurvival pages 1-4) S. cerevisiae Dube et al. 2023 2023-11 https://doi.org/10.1007/s42977-023-00192-1 Not CCT6-specific, but relevant recent pathway context for the complex in yeast.
Recent development: kinetic mechanism A 2023 yeast study on CCT2 found reduced ADP off-rate in a disease-linked mutant and quantified WT ATPase behavior (K1 ~8.3 µM, K2 ~110 µM; kcat ~0.043–0.053 s^-1), reinforcing asymmetric ATPase cycling within yeast TRiC relevant to low-affinity subunits such as CCT6 (roy2023reducedadpoffrate pages 1-2, kelly2020structuralandfunctional pages 42-48) Yeast TRiC/CCT Roy et al. 2023; Kelly 2020 2023-08; 2020 https://doi.org/10.1038/s42003-023-05261-8 ; n/a Quantitative kinetics are for CCT2/whole complex, not directly for CCT6, but they support the asymmetric ring model.
Recent development: cochaperone cooperation 2024 cryo-EM/XL-MS work showed PhLP2A and substrate actin occupy opposing TRiC chambers; actin/PhLP2A contact positively charged inner-surface residues from CCT1/3/6/8, implicating CCT6 directly in the substrate/cochaperone folding chamber interface (junsun2024astructuralvista pages 1-2) Purified TRiC system Park et al. 2024 2024-02 https://doi.org/10.1038/s41467-024-45242-x Strong recent mechanistic evidence, though not yeast-specific in organism designation.

Table: This table summarizes experimentally supported functional annotation evidence for yeast CCT6/YDR188W/P39079, emphasizing identity verification, complex role, subunit specialization, genetics, localization, and 2023-2024 developments. It is useful as a compact evidence map for building a narrative report while keeping organism-specific claims separate from broader TRiC/CCT findings.

1) Gene/protein identity verification (disambiguation)

The target is yeast CCT6 (ordered locus name YDR188W; UniProt P39079), a TRiC/CCT subunit (Cct6p). Yeast-focused primary literature explicitly treats CCT6 as a chaperonin subunit gene and performs yeast genetics with cct6 alleles and CCT6 overexpression constructs, consistent with the UniProt record and domain/family assignment (TCP-1 chaperonin family). (kabir2005physiologicaleffectsof pages 1-2, kabir2005physiologicaleffectsof pages 2-4)

2) Key concepts and definitions (current understanding)

2.1 TRiC/CCT as a eukaryotic group II chaperonin

TRiC/CCT (TCP-1 Ring Complex / Chaperonin Containing TCP-1) is an essential eukaryotic chaperonin that forms two stacked rings, each ring containing eight different subunits (CCT1–CCT8) in a fixed arrangement, producing a central chamber where folding can proceed under “caged” conditions coupled to an ATP-driven conformational cycle. (grantham2020themolecularchaperone pages 1-2, gvozdenov2024triccctchaperoningoverns pages 1-6)

2.2 Substrate spectrum and “primary function” framing for CCT6

For functional annotation, the most defensible “primary function” for CCT6 is: a structural/ATPase subunit of the TRiC/CCT chaperonin that contributes to ATP-dependent folding and maturation of obligate cytosolic substrates, especially actin and tubulin, and other topologically complex clients. Reviews emphasize that actin and tubulin are core/obligate CCT substrates, and TRiC also contributes to assembly of select multiprotein complexes (e.g., VHL–Elongin) and interacts with regulators (e.g., gelsolin) in a non-classical chaperoning mode. (grantham2020themolecularchaperone pages 1-2, willison2018thestructureand pages 1-2)

2.3 Subunit specialization within TRiC/CCT

Unlike bacterial GroEL (homooligomer), TRiC is heterooligomeric, allowing subunit-specific substrate contacts and asymmetric ATPase/allosteric behavior. Experimental and structural analyses (summarized in yeast TRiC-focused work) group subunits into two “hemispheres” with differing nucleotide affinity and ATPase roles. CCT6 is consistently placed in the low ATP-affinity hemisphere (with CCT3/6/7/8), with sequence divergence near the nucleotide pocket proposed to reduce nucleotide exchange/ATP binding; yeast mutational data indicate that ATPase/P-loop disruption is more deleterious in high-affinity subunits than in low-affinity ones. (kelly2020structuralandfunctionala pages 42-48, kelly2020structuralandfunctional pages 42-48)

3) Molecular/structural annotation of yeast Cct6p

3.1 Subunit position in the yeast TRiC/CCT ring

A yeast internal-subunit eGFP labeling strategy combined with cryo-EM (YISEL) enabled unambiguous subunit assignment in yeast TRiC, including CCT6. This work assigns CCT6 as an on-axis subunit and places it at a defined position in the ring architecture (Figure evidence). (zang2018developmentofa pages 1-2, zang2018developmentofa media 20a150a9)

3.2 Structural role during ring closure and inter-ring communication

Structural analyses summarized for yeast TRiC indicate that the N-terminus of CCT6 participates in an inter-ring interaction network during closure, stacking with the trans ring alongside other low-affinity hemisphere subunits. This supports the view that CCT6 contributes importantly to mechanical/structural coupling of the two rings through the ATP-driven cycle, even if its own ATPase contribution is reduced relative to high-affinity subunits. (kelly2020structuralandfunctionala pages 42-48, kelly2020structuralandfunctional pages 42-48)

4) Cellular localization and where Cct6p acts

4.1 Canonical localization: cytosolic proteostasis

TRiC/CCT is classically considered a cytosolic folding machine that supports co-/post-translational maturation of a substantial fraction of the proteome. Yeast-focused work explicitly reiterates TRiC/CCT as a cytosolic cylindrical complex encoded by eight essential genes and contributing to folding of ~10% of yeast cellular polypeptides. (dube2023saccharomycescerevisiaesurvival pages 1-4)

4.2 Emerging localization/function: nuclear TRiC/CCT

A 2024 preprint reports TRiC/CCT is present in the nucleus and proposes a direct role in regulating RNA polymerase II activity and nascent RNA production (with effects persisting when TRiC is restricted to the cytoplasm, supporting a direct nuclear role in their model). This expands likely functional contexts for all TRiC subunits (including CCT6), although it does not isolate a CCT6-specific nuclear mechanism. (gvozdenov2024triccctchaperoningoverns pages 1-6)

5) Yeast genetics: essentiality, phenotypes, and CCT6-specific functional inferences

5.1 Essentiality

Yeast gene disruption experiments and genetic summaries state that all eight CCT genes (CCT1–CCT8) are essential, which includes CCT6. (kabir2008overexpressedribosomalproteins pages 1-2, kabir2005physiologicaleffectsof pages 2-4)

5.2 Conditional alleles and cytoskeleton-linked phenotypes

A panel of temperature-sensitive cct6 alleles has been described (e.g., cct6-14, -18, -27, -74, -85, -93, -97). Reported phenotypes include TBZ sensitivity (consistent with microtubule-associated stress) and in some alleles NaCl sensitivity (often used as an actin/cytoskeleton stress readout in these legacy screens). (kabir2008overexpressedribosomalproteins pages 1-2, kabir2008overexpressedribosomalproteins pages 2-3)

5.3 Multicopy suppression: unassembled Cct6p as a functional entity

A central yeast-specific insight is that overexpression of CCT6 can suppress diverse conditional phenotypes, including defects caused by tor2-21, lst8-2, rsp5-9, and growth inhibition caused by concomitant overexpression of Sit4p and Sap155p. Importantly, fractionation/abundance analysis indicates that overexpressing CCT6 increases the level of unassociated (unassembled) Cct6p, while the assembled TRiC/CCT complex remains at normal levels—supporting a model where unassembled Cct6p has physiological effects (e.g., substrate sequestration/competition for modifying activities) beyond simply boosting holo-complex abundance. (kabir2005physiologicaleffectsof pages 1-2, kabir2005physiologicaleffectsof pages 2-4)

5.4 Separation-of-function: ATP-binding motif required for suppression but not viability

Kabir et al. examined many altered forms of Cct6p and report that a CCT6 allele with GDGTT→AAAAA substitutions in the conserved ATP-binding motif (cct6-24) is unable to suppress the above traits, yet is functional for growth. This strongly supports that (i) Cct6p has separable functional states and (ii) suppression by unassembled Cct6p likely requires a specific ATP-associated conformation or activity. (kabir2005physiologicaleffectsof pages 1-2)

5.5 Proteome-scale phenotyping distinguishes CCT6 from other subunits

High-throughput microscopy profiling comparing ATP-site mutants in different TRiC subunits found that CCT subunits can have distinguishable in vivo consequences; in particular, the study emphasizes that the CCT3 mutant showed stronger associations with Q/N-rich proteins and P-body phenotypes than the CCT6 mutant, consistent with subunit-specific substrate/interactome specialization. (nadlerholly2012interactionsofsubunit pages 1-2)

6) Pathways and biological processes linked to CCT6/TRiC in yeast

6.1 TOR signaling / actin polarization axis

Overexpression of CCT6 suppresses tor2-21 conditional phenotypes and is linked to partial restoration of actin cytoskeleton polarization in that genetic background, tying TRiC/CCT (and/or unassembled Cct6p) to a TOR2-dependent actin organization pathway. (kabir2005physiologicaleffectsof pages 2-4)

6.2 Trafficking/cell wall integrity and ubiquitin ligase connections

CCT6 overexpression suppresses phenotypes of lst8-2 (a TOR-associated factor required for sorting of diverse proteins at the Golgi and associated with cell wall integrity) and rsp5-9 (an essential ubiquitin–protein ligase with broad roles including endocytosis and actin dynamics). These suppression relationships suggest that TRiC/CCT proteostasis capacity and/or Cct6p-mediated sequestration can buffer defects in trafficking, membrane protein turnover, and cell surface/cell wall regulation. (kabir2005physiologicaleffectsof pages 2-4)

6.3 Stress physiology and the cell wall integrity MAPK pathway (recent)

A 2023 yeast study using a folding-defective cct7 mutant reports temperature and cell-wall-stressor sensitivity and rescue by overexpression of PKC1 and SLT2 (MAPK cell wall integrity pathway components), supporting a functional interface between TRiC/CCT-dependent folding and cell-wall integrity signaling under heat stress. While not CCT6-specific, it is relevant to interpreting downstream consequences of impaired TRiC activity in yeast and potential contexts where CCT6 alleles may manifest. (dube2023saccharomycescerevisiaesurvival pages 1-4)

7) Recent developments (prioritizing 2023–2024)

7.1 Quantitative TRiC kinetics in yeast (2023)

A 2023 study analyzing yeast TRiC with disease-associated mutations in CCT2 quantified ATPase behavior and reported apparent ATP binding constants and turnover (e.g., WT K1 ~8.3 μM, K2 ~110 μM; kcat ~0.043–0.053 s−1 under their fitted model) and showed that a double mutation reduces ADP off-rate, stabilizing closed states. This strengthens the mechanistic framework in which different subunits contribute differently to allosteric cycling—contextually relevant to CCT6 as a low-affinity hemisphere member—even though the mutation is in CCT2 rather than CCT6. (roy2023reducedadpoffrate pages 1-2, kelly2020structuralandfunctional pages 42-48)

7.2 TRiC cochaperone cooperation and CCT6 contact surfaces (2024)

A 2024 cryo-EM/XL-MS study of TRiC cooperation with PhLP2A (phosducin-like protein) in the folding cycle reports that in the presence of substrate, actin and PhLP2A segregate into opposing chambers, each binding positively charged inner surface residues from CCT1/3/6/8. This provides modern structural evidence that CCT6 contributes directly to the physicochemical environment and binding surfaces engaged during actin folding intermediates. (junsun2024astructuralvista pages 1-2)

7.3 Nuclear TRiC and transcriptional homeostasis in yeast (2024 preprint)

A 2024 yeast study proposes TRiC/CCT has a direct nuclear role modulating RNA polymerase II activity and nascent RNA output, suggesting TRiC contributes to cell homeostasis beyond canonical cytosolic folding. This is a notable expansion of functional annotation scope for the complex and likely relevant to CCT6 as a subunit, but remains preprint-stage and not subunit-resolved. (gvozdenov2024triccctchaperoningoverns pages 1-6)

8) Current applications and real-world implementations

8.1 Yeast as a functional-genomics platform to probe chaperonin subunits

CCT6 is used experimentally as (i) a genetically essential proteostasis component (ts alleles) and (ii) a multicopy suppressor whose overexpression reveals buffering relationships across major pathways (TOR signaling, trafficking/cell wall, ubiquitin-mediated regulation). This makes CCT6 a practical tool for dissecting genetic robustness and proteostasis-pathway crosstalk in an industrially and medically relevant model organism. (kabir2005physiologicaleffectsof pages 1-2, kabir2008overexpressedribosomalproteins pages 2-3)

8.2 Structural biology and engineering of macromolecular machines

The YISEL internal labeling method demonstrated in yeast TRiC enables precise subunit assignment in challenging hetero-oligomeric complexes and is itself an implementation with broader utility for macromolecular complex annotation and cryo-EM mapping—directly leveraging yeast CCT6 subunit labeling/assignment. (zang2018developmentofa pages 1-2, zang2018developmentofa media 20a150a9)

8.3 Disease analogy and mechanistic transfer (caveated)

While human disease phenotypes are not part of yeast CCT6 annotation per se, yeast TRiC studies (e.g., kinetic analysis of disease-linked CCT2 mutations) illustrate how yeast TRiC serves as a mechanistic model for conserved chaperonin function and allosteric defects. Any extension to CCT6-related human disease or therapeutic targeting should be made cautiously and requires direct evidence not provided here. (roy2023reducedadpoffrate pages 1-2)

9) Relevant statistics and quantitative data (from retrieved sources)

  • Essential genes: CCT1–CCT8 are essential in yeast. (kabir2008overexpressedribosomalproteins pages 1-2, kabir2005physiologicaleffectsof pages 2-4)
  • Proteostasis workload estimate: TRiC/CCT contributes to folding of ~10% of yeast cellular polypeptides (as stated in yeast stress study background). (dube2023saccharomycescerevisiaesurvival pages 1-4)
  • Suppression screen scale: 22 multicopy suppressors were isolated for a cct4 ts allele; 14 encoded ribosomal proteins; some suppressors also acted on cct6 alleles. (kabir2008overexpressedribosomalproteins pages 1-2, kabir2008overexpressedribosomalproteins pages 2-3)
  • TRiC ATPase kinetics (yeast, WT): apparent ATP binding constants (K1 ~8.3 μM, K2 ~110 μM) and turnover (kcat ~0.043–0.053 s−1) reported in one fitted model/condition set. (roy2023reducedadpoffrate pages 1-2)

10) Expert interpretation and limitations

  1. Most CCT6-specific “function” evidence in yeast is genetic (essentiality; ts alleles; multicopy suppression; separation-of-function for suppression vs viability), while client specificity is more firmly established at the TRiC complex level (actin/tubulin and select other classes). Therefore, the most accurate functional annotation for CCT6 is as a TRiC/CCT subunit that supports folding of obligate cytosolic substrates and TRiC conformational cycling, with additional evidence that unassembled Cct6p can modulate cell physiology in an ATP-motif–dependent manner. (kabir2005physiologicaleffectsof pages 1-2, grantham2020themolecularchaperone pages 1-2)
  2. Recent 2023–2024 research largely refines TRiC mechanism, stress crosstalk, and nuclear roles, but is not yet fully subunit-resolved for CCT6 in yeast. The strongest 2024 subunit-level mechanistic link involving CCT6 is structural evidence that CCT6 contributes inner-surface residues contacted in the actin/PhLP2A folding context. (junsun2024astructuralvista pages 1-2)

Key cited sources (with dates and URLs)

  • Kabir MA et al. Physiological effects of unassembled chaperonin Cct subunits in the yeast Saccharomyces cerevisiae. Yeast. Feb 2005. https://doi.org/10.1002/yea.1210 (kabir2005physiologicaleffectsof pages 1-2)
  • Kabir MA & Sherman F. Overexpressed ribosomal proteins suppress defective chaperonins in Saccharomyces cerevisiae. FEMS Yeast Research. Dec 2008. https://doi.org/10.1111/j.1567-1364.2008.00425.x (kabir2008overexpressedribosomalproteins pages 1-2)
  • Zang Y et al. Development of a yeast internal-subunit eGFP labeling strategy… TRiC/CCT. Scientific Reports. Feb 2018. https://doi.org/10.1038/s41598-017-18962-y (zang2018developmentofa pages 1-2)
  • Willison KR. The structure and evolution of eukaryotic chaperonin-containing TCP-1… folds actin. Biochemical Journal. Oct 2018. https://doi.org/10.1042/BCJ20170378 (willison2018thestructureand pages 1-2)
  • Grantham J. The Molecular Chaperone CCT/TRiC… Frontiers in Genetics. Mar 2020. https://doi.org/10.3389/fgene.2020.00172 (grantham2020themolecularchaperone pages 1-2)
  • Roy M et al. Reduced ADP off-rate… yeast CCT2 double mutation… Communications Biology. Aug 2023. https://doi.org/10.1038/s42003-023-05261-8 (roy2023reducedadpoffrate pages 1-2)
  • Dube A et al. S. cerevisiae survival against heat stress entails… CCT and cell wall integrity pathway. Biologia Futura. Nov 2023. https://doi.org/10.1007/s42977-023-00192-1 (dube2023saccharomycescerevisiaesurvival pages 1-4)
  • Park J et al. A structural vista of PhLP2A–TRiC cooperation… Nature Communications. Feb 2024. https://doi.org/10.1038/s41467-024-45242-x (junsun2024astructuralvista pages 1-2)
  • Gvozdenov Z et al. TRiC/CCT Chaperonin Governs RNA Polymerase II Activity in the Nucleus… bioRxiv preprint. Sep 26, 2024. https://doi.org/10.1101/2024.09.26.615188 (gvozdenov2024triccctchaperoningoverns pages 1-6)

References

  1. (grantham2020themolecularchaperone pages 1-2): Julie Grantham. The molecular chaperone cct/tric: an essential component of proteostasis and a potential modulator of protein aggregation. Frontiers in Genetics, Mar 2020. URL: https://doi.org/10.3389/fgene.2020.00172, doi:10.3389/fgene.2020.00172. This article has 139 citations and is from a peer-reviewed journal.

  2. (dube2023saccharomycescerevisiaesurvival pages 1-4): Ankita Dube, Dileep Pullepu, and M. Anaul Kabir. Saccharomyces cerevisiae survival against heat stress entails a communication between cct and cell wall integrity pathway. Biologia futura, 74:519-527, Nov 2023. URL: https://doi.org/10.1007/s42977-023-00192-1, doi:10.1007/s42977-023-00192-1. This article has 2 citations and is from a peer-reviewed journal.

  3. (kabir2005physiologicaleffectsof pages 1-2): M. Anaul Kabir, Joanna Kaminska, George B. Segel, Gabor Bethlendy, Paul Lin, Flavio Della Seta, Casey Blegen, Kristine M. Swiderek, Teresa ?o??dek, Kim T. Arndt, and Fred Sherman. Physiological effects of unassembled chaperonin cct subunits in the yeast saccharomyces cerevisiae. Yeast, 22:219-239, Feb 2005. URL: https://doi.org/10.1002/yea.1210, doi:10.1002/yea.1210. This article has 60 citations and is from a peer-reviewed journal.

  4. (kabir2005physiologicaleffectsof pages 2-4): M. Anaul Kabir, Joanna Kaminska, George B. Segel, Gabor Bethlendy, Paul Lin, Flavio Della Seta, Casey Blegen, Kristine M. Swiderek, Teresa ?o??dek, Kim T. Arndt, and Fred Sherman. Physiological effects of unassembled chaperonin cct subunits in the yeast saccharomyces cerevisiae. Yeast, 22:219-239, Feb 2005. URL: https://doi.org/10.1002/yea.1210, doi:10.1002/yea.1210. This article has 60 citations and is from a peer-reviewed journal.

  5. (zang2018developmentofa pages 1-2): Yunxiang Zang, Huping Wang, Zhicheng Cui, Mingliang Jin, Caixuan Liu, Wenyu Han, Yanxing Wang, and Yao Cong. Development of a yeast internal-subunit egfp labeling strategy and its application in subunit identification in eukaryotic group ii chaperonin tric/cct. Scientific Reports, Feb 2018. URL: https://doi.org/10.1038/s41598-017-18962-y, doi:10.1038/s41598-017-18962-y. This article has 22 citations and is from a peer-reviewed journal.

  6. (kabir2008overexpressedribosomalproteins pages 1-2): M. Anaul Kabir and Fred Sherman. Overexpressed ribosomal proteins suppress defective chaperonins in saccharomyces cerevisiae. FEMS yeast research, 8 8:1236-44, Dec 2008. URL: https://doi.org/10.1111/j.1567-1364.2008.00425.x, doi:10.1111/j.1567-1364.2008.00425.x. This article has 21 citations and is from a peer-reviewed journal.

  7. (kelly2020structuralandfunctional pages 18-23): J Kelly. Structural and functional characterisation of the group ii chaperonin cct/tric. Unknown journal, 2020.

  8. (willison2018thestructureand pages 1-2): Keith Robert Willison. The structure and evolution of eukaryotic chaperonin-containing tcp-1 and its mechanism that folds actin into a protein spring. The Biochemical journal, 475 19:3009-3034, Oct 2018. URL: https://doi.org/10.1042/bcj20170378, doi:10.1042/bcj20170378. This article has 42 citations.

  9. (kelly2020structuralandfunctionala pages 42-48): J Kelly. Structural and functional characterisation of the group ii chaperonin cct/tric. Unknown journal, 2020.

  10. (kelly2020structuralandfunctional pages 42-48): J Kelly. Structural and functional characterisation of the group ii chaperonin cct/tric. Unknown journal, 2020.

  11. (dube2021chaperoninpointmutation pages 1-4): Ankita Dube and M. Anaul Kabir. Chaperonin point mutation enhances cadmium endurance in saccharomyces cerevisiae. Biotechnology Letters, 43:1735-1745, May 2021. URL: https://doi.org/10.1007/s10529-021-03151-9, doi:10.1007/s10529-021-03151-9. This article has 2 citations and is from a peer-reviewed journal.

  12. (zang2018developmentofa media 20a150a9): Yunxiang Zang, Huping Wang, Zhicheng Cui, Mingliang Jin, Caixuan Liu, Wenyu Han, Yanxing Wang, and Yao Cong. Development of a yeast internal-subunit egfp labeling strategy and its application in subunit identification in eukaryotic group ii chaperonin tric/cct. Scientific Reports, Feb 2018. URL: https://doi.org/10.1038/s41598-017-18962-y, doi:10.1038/s41598-017-18962-y. This article has 22 citations and is from a peer-reviewed journal.

  13. (kabir2008overexpressedribosomalproteins pages 2-3): M. Anaul Kabir and Fred Sherman. Overexpressed ribosomal proteins suppress defective chaperonins in saccharomyces cerevisiae. FEMS yeast research, 8 8:1236-44, Dec 2008. URL: https://doi.org/10.1111/j.1567-1364.2008.00425.x, doi:10.1111/j.1567-1364.2008.00425.x. This article has 21 citations and is from a peer-reviewed journal.

  14. (nadlerholly2012interactionsofsubunit pages 1-2): Michal Nadler-Holly, Michal Breker, Ranit Gruber, Ariel Azia, Melissa Gymrek, Miriam Eisenstein, Keith R. Willison, Maya Schuldiner, and Amnon Horovitz. Interactions of subunit cct3 in the yeast chaperonin cct/tric with q/n-rich proteins revealed by high-throughput microscopy analysis. Proceedings of the National Academy of Sciences, 109:18833-18838, Oct 2012. URL: https://doi.org/10.1073/pnas.1209277109, doi:10.1073/pnas.1209277109. This article has 52 citations and is from a highest quality peer-reviewed journal.

  15. (gvozdenov2024triccctchaperoningoverns pages 1-6): Zlata Gvozdenov, Audrey Yi Tyan Peng, Anusmita Biswas, Zeno Barcutean, Daniel Gestaut, Judith Frydman, Kevin Struhl, and Brian C. Freeman. Tric/cct chaperonin governs rna polymerase ii activity in the nucleus to support rna homeostasis. bioRxiv, Sep 2024. URL: https://doi.org/10.1101/2024.09.26.615188, doi:10.1101/2024.09.26.615188. This article has 3 citations.

  16. (roy2023reducedadpoffrate pages 1-2): Mousam Roy, Rachel C. Fleisher, Alexander I. Alexandrov, and Amnon Horovitz. Reduced adp off-rate by the yeast cct2 double mutation t394p/r510h which causes leber congenital amaurosis in humans. Communications Biology, Aug 2023. URL: https://doi.org/10.1038/s42003-023-05261-8, doi:10.1038/s42003-023-05261-8. This article has 9 citations and is from a peer-reviewed journal.

  17. (junsun2024astructuralvista pages 1-2): Junsun Park, Hyunmin Kim, Daniel Gestaut, Seyeon Lim, Kwadwo A. Opoku-Nsiah, Alexander Leitner, Judith Frydman, and Soung-Hun Roh. A structural vista of phosducin-like phlp2a-chaperonin tric cooperation during the atp-driven folding cycle. Nature Communications, Feb 2024. URL: https://doi.org/10.1038/s41467-024-45242-x, doi:10.1038/s41467-024-45242-x. This article has 16 citations and is from a highest quality peer-reviewed journal.

Citations

  1. dube2021chaperoninpointmutation pages 1-4
  2. kabir2005physiologicaleffectsof pages 1-2
  3. nadlerholly2012interactionsofsubunit pages 1-2
  4. gvozdenov2024triccctchaperoningoverns pages 1-6
  5. dube2023saccharomycescerevisiaesurvival pages 1-4
  6. junsun2024astructuralvista pages 1-2
  7. kabir2005physiologicaleffectsof pages 2-4
  8. roy2023reducedadpoffrate pages 1-2
  9. kabir2008overexpressedribosomalproteins pages 1-2
  10. zang2018developmentofa pages 1-2
  11. willison2018thestructureand pages 1-2
  12. grantham2020themolecularchaperone pages 1-2
  13. kelly2020structuralandfunctional pages 18-23
  14. kelly2020structuralandfunctionala pages 42-48
  15. kelly2020structuralandfunctional pages 42-48
  16. kabir2008overexpressedribosomalproteins pages 2-3
  17. SIT4 SAP155
  18. https://doi.org/10.1002/yea.1210
  19. https://doi.org/10.3389/fgene.2020.00172
  20. https://doi.org/10.1038/s41598-017-18962-y
  21. https://doi.org/10.1111/j.1567-1364.2008.00425.x
  22. https://doi.org/10.1042/BCJ20170378
  23. https://doi.org/10.1007/s10529-021-03151-9
  24. https://doi.org/10.1073/pnas.1209277109
  25. https://doi.org/10.1101/2024.09.26.615188
  26. https://doi.org/10.1007/s42977-023-00192-1
  27. https://doi.org/10.1038/s42003-023-05261-8
  28. https://doi.org/10.1038/s41467-024-45242-x
  29. https://doi.org/10.3389/fgene.2020.00172,
  30. https://doi.org/10.1007/s42977-023-00192-1,
  31. https://doi.org/10.1002/yea.1210,
  32. https://doi.org/10.1038/s41598-017-18962-y,
  33. https://doi.org/10.1111/j.1567-1364.2008.00425.x,
  34. https://doi.org/10.1042/bcj20170378,
  35. https://doi.org/10.1007/s10529-021-03151-9,
  36. https://doi.org/10.1073/pnas.1209277109,
  37. https://doi.org/10.1101/2024.09.26.615188,
  38. https://doi.org/10.1038/s42003-023-05261-8,
  39. https://doi.org/10.1038/s41467-024-45242-x,

📄 View Raw YAML

id: P39079
gene_symbol: CCT6
product_type: PROTEIN
status: COMPLETE
taxon:
  id: NCBITaxon:559292
  label: Saccharomyces cerevisiae
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.
references:
- id: GO_REF:0000002
  title: Gene Ontology annotation through association of InterPro records with GO terms
  findings: []
- id: GO_REF:0000033
  title: Annotation inferences using phylogenetic trees
  findings: []
- id: GO_REF:0000043
  title: Gene Ontology annotation based on UniProtKB/Swiss-Prot keyword mapping
  findings: []
- id: GO_REF:0000044
  title: >-
    Gene Ontology annotation based on UniProtKB/Swiss-Prot Subcellular Location vocabulary mapping, accompanied
    by conservative changes to GO terms applied by UniProt
  findings: []
- id: GO_REF:0000117
  title: Electronic Gene Ontology annotations created by ARBA machine learning models
  findings: []
- id: GO_REF:0000120
  title: Combined Automated Annotation using Multiple IEA Methods
  findings: []
- id: PMID:16554755
  title: Global landscape of protein complexes in the yeast Saccharomyces cerevisiae.
  findings: []
- id: PMID:16762366
  title: >-
    Quantitative actin folding reactions using yeast CCT purified via an internal tag in the CCT3/gamma
    subunit.
  findings:
  - statement: >-
      Purified yeast CCT, tagged through CCT3, catalyzes ATP-dependent actin folding; this supports protein-folding
      and chaperonin activity annotations for CCT6 as a TRiC/CCT subunit.
    supporting_text: >-
      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
- id: PMID:15704212
  title: Physiological effects of unassembled chaperonin Cct subunits in the yeast Saccharomyces cerevisiae.
  findings:
  - statement: Yeast CCT is a double-ring complex with a stoichiometric set of eight distinct Cct subunits.
    supporting_text: >-
      Eukaryotic chaperonins, the Cct complexes, are assembled into two rings, each of which is composed
      of a stoichiometric array of eight different subunits
- id: PMID:19536198
  title: >-
    An atlas of chaperone-protein interactions in Saccharomyces cerevisiae: implications to protein folding
    pathways in the cell.
  findings:
  - statement: >-
      The chaperone interactome study is useful context for CCT contacts but reports indirect TAP-tag
      interactions rather than a specific molecular activity.
    supporting_text: >-
      It should be emphasized that the interactions presented are indirect TAP-tag based interactions
      and not direct binary interactions.
- id: PMID:37968396
  title: The social and structural architecture of the yeast protein interactome.
  findings: []
- id: file:yeast/CCT6/CCT6-deep-research-falcon.md
  title: Falcon deep research report for CCT6
  findings:
  - statement: >-
      The Falcon report was reviewed and synthesized into the CCT6 curation, including core-function framing,
      family/PANTHER context, and evidence limitations.
existing_annotations:
- term:
    id: GO:0006457
    label: protein folding
  qualifier: involved_in
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  review:
    summary: >-
      CCT6 participates in protein folding as an obligate subunit of TRiC/CCT, the cytosolic chaperonin
      that folds actin, tubulin, and other clients.
    action: ACCEPT
    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.
    supported_by:
    - reference_id: file:yeast/CCT6/CCT6-deep-research-falcon.md
      supporting_text: a structural/ATPase subunit of the TRiC/CCT chaperonin
- term:
    id: GO:0005832
    label: chaperonin-containing T-complex
  qualifier: part_of
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  review:
    summary: CCT6 is a named subunit of the chaperonin-containing T-complex.
    action: ACCEPT
    reason: >-
      Complex membership is central to the gene product function and is supported by yeast CCT complex
      literature and family evidence.
- term:
    id: GO:0051082
    label: unfolded protein binding
  qualifier: enables
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  review:
    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.
    action: MODIFY
    reason: >-
      Replace generic substrate-binding language with the specific chaperonin activity supported by yeast
      CCT actin-folding assays and domain evidence.
    proposed_replacement_terms:
    - id: GO:0140662
      label: ATP-dependent protein folding chaperone
- term:
    id: GO:0000166
    label: nucleotide binding
  qualifier: enables
  evidence_type: IEA
  original_reference_id: GO_REF:0000043
  review:
    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.
    action: MARK_AS_OVER_ANNOTATED
    reason: >-
      Generic nucleotide binding does not add useful functional information beyond the more specific ATP-related
      chaperonin annotations already present.
- term:
    id: GO:0005524
    label: ATP binding
  qualifier: enables
  evidence_type: IEA
  original_reference_id: GO_REF:0000120
  review:
    summary: >-
      CCT6 contains a conserved chaperonin ATP-binding site, but ATP binding alone is a domain property
      rather than the core biological function.
    action: KEEP_AS_NON_CORE
    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.
- term:
    id: GO:0005737
    label: cytoplasm
  qualifier: located_in
  evidence_type: IEA
  original_reference_id: GO_REF:0000044
  review:
    summary: CCT6 functions as part of the cytosolic TRiC/CCT chaperonin.
    action: ACCEPT
    reason: Cytoplasm is the established location of the CCT/TRiC folding machine.
- term:
    id: GO:0005832
    label: chaperonin-containing T-complex
  qualifier: part_of
  evidence_type: IEA
  original_reference_id: GO_REF:0000117
  review:
    summary: CCT6 is a named subunit of the chaperonin-containing T-complex.
    action: ACCEPT
    reason: >-
      Complex membership is central to the gene product function and is supported by yeast CCT complex
      literature and family evidence.
- term:
    id: GO:0006457
    label: protein folding
  qualifier: involved_in
  evidence_type: IEA
  original_reference_id: GO_REF:0000120
  review:
    summary: >-
      CCT6 participates in protein folding as an obligate subunit of TRiC/CCT, the cytosolic chaperonin
      that folds actin, tubulin, and other clients.
    action: ACCEPT
    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.
- term:
    id: GO:0016887
    label: ATP hydrolysis activity
  qualifier: enables
  evidence_type: IEA
  original_reference_id: GO_REF:0000002
  review:
    summary: >-
      CCT6 is a TCP-1/CCT chaperonin subunit with conserved ATPase machinery that powers TRiC/CCT conformational
      cycling.
    action: ACCEPT
    reason: >-
      ATP hydrolysis is a defensible subunit-level molecular function for CCT family members and is directly
      tied to the chaperonin folding cycle.
- term:
    id: GO:0051082
    label: unfolded protein binding
  qualifier: enables
  evidence_type: IEA
  original_reference_id: GO_REF:0000120
  review:
    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.
    action: MODIFY
    reason: >-
      Replace generic substrate-binding language with the specific chaperonin activity supported by yeast
      CCT actin-folding assays and domain evidence.
    proposed_replacement_terms:
    - id: GO:0140662
      label: ATP-dependent protein folding chaperone
- term:
    id: GO:0140662
    label: ATP-dependent protein folding chaperone
  qualifier: enables
  evidence_type: IEA
  original_reference_id: GO_REF:0000002
  review:
    summary: CCT6 is an obligate subunit of the ATP-dependent TRiC/CCT folding machine.
    action: ACCEPT
    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.
    supported_by:
    - reference_id: PMID:16762366
      supporting_text: >-
        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
      reference_section_type: ABSTRACT
- term:
    id: GO:0005515
    label: protein binding
  qualifier: enables
  evidence_type: IPI
  original_reference_id: PMID:16554755
  supporting_entities:
  - UniProtKB:P39078
  review:
    summary: >-
      protein binding is too generic for a CCT subunit and does not describe the chaperonin mechanism
      or substrate class.
    action: MARK_AS_OVER_ANNOTATED
    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.
- term:
    id: GO:0005515
    label: protein binding
  qualifier: enables
  evidence_type: IPI
  original_reference_id: PMID:19536198
  supporting_entities:
  - UniProtKB:P39078
  review:
    summary: >-
      protein binding is too generic for a CCT subunit and does not describe the chaperonin mechanism
      or substrate class.
    action: MARK_AS_OVER_ANNOTATED
    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.
    supported_by:
    - reference_id: PMID:19536198
      supporting_text: >-
        It should be emphasized that the interactions presented are indirect TAP-tag based interactions
        and not direct binary interactions.
- term:
    id: GO:0005515
    label: protein binding
  qualifier: enables
  evidence_type: IPI
  original_reference_id: PMID:37968396
  supporting_entities:
  - UniProtKB:P39078
  review:
    summary: >-
      protein binding is too generic for a CCT subunit and does not describe the chaperonin mechanism
      or substrate class.
    action: MARK_AS_OVER_ANNOTATED
    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.
- term:
    id: GO:0006457
    label: protein folding
  qualifier: involved_in
  evidence_type: IDA
  original_reference_id: PMID:16762366
  review:
    summary: >-
      CCT6 participates in protein folding as an obligate subunit of TRiC/CCT, the cytosolic chaperonin
      that folds actin, tubulin, and other clients.
    action: ACCEPT
    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.
    supported_by:
    - reference_id: PMID:16762366
      supporting_text: >-
        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
      reference_section_type: ABSTRACT
- term:
    id: GO:0005832
    label: chaperonin-containing T-complex
  qualifier: part_of
  evidence_type: IDA
  original_reference_id: PMID:16762366
  review:
    summary: CCT6 is a named subunit of the chaperonin-containing T-complex.
    action: ACCEPT
    reason: >-
      Complex membership is central to the gene product function and is supported by yeast CCT complex
      literature and family evidence.
    supported_by:
    - reference_id: PMID:16762366
      supporting_text: >-
        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
      reference_section_type: ABSTRACT
- term:
    id: GO:0051082
    label: unfolded protein binding
  qualifier: enables
  evidence_type: IDA
  original_reference_id: PMID:16762366
  review:
    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.
    action: MODIFY
    reason: >-
      Replace generic substrate-binding language with the specific chaperonin activity supported by yeast
      CCT actin-folding assays and domain evidence.
    proposed_replacement_terms:
    - id: GO:0140662
      label: ATP-dependent protein folding chaperone
    supported_by:
    - reference_id: PMID:16762366
      supporting_text: >-
        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
      reference_section_type: ABSTRACT
core_functions:
- description: >-
    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:
    id: GO:0016887
    label: ATP hydrolysis activity
  contributes_to_molecular_function:
    id: GO:0140662
    label: ATP-dependent protein folding chaperone
  directly_involved_in:
  - id: GO:0006457
    label: protein folding
  locations:
  - id: GO:0005737
    label: cytoplasm
  in_complex:
    id: GO:0005832
    label: chaperonin-containing T-complex
  supported_by:
  - reference_id: PMID:16762366
    supporting_text: >-
      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
    reference_section_type: ABSTRACT
  - reference_id: PMID:15704212
    supporting_text: >-
      Eukaryotic chaperonins, the Cct complexes, are assembled into two rings, each of which is composed
      of a stoichiometric array of eight different subunits
    reference_section_type: ABSTRACT
suggested_questions:
- question: >-
    Which physiological effects of CCT6 overexpression are caused by unassembled Cct6p versus altered
    flux through assembled TRiC/CCT?
suggested_experiments:
- hypothesis: >-
    Unassembled Cct6p suppresses selected conditional phenotypes by sequestering or buffering client proteins
    independently of increasing assembled TRiC/CCT.
  description: >-
    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.
  experiment_type: native complex profiling with affinity purification and genetic suppression assays