CCT5

UniProt ID: P40413
Organism: Saccharomyces cerevisiae
Review Status: COMPLETE
πŸ“ Provide Detailed Feedback

Gene Description

CCT5 encodes the epsilon subunit of the cytosolic group II chaperonin TRiC/CCT. Cct5 is an obligate subunit of the ATP-driven double-ring folding machine, contributes one ATPase/substrate-contact module to the chamber, and is best curated as part of the complex that folds actin, tubulin, and other cytosolic clients. The subunit-specific literature emphasizes ATP-cycle asymmetry and chamber architecture rather than a separate standalone activity.

Existing Annotations Review

GO Term Evidence Action Reason
GO:0006457 protein folding
IBA
GO_REF:0000033
ACCEPT
Summary: CCT5 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/CCT5/CCT5-deep-research-falcon.md
CCT5 is best defined as a **structural and catalytic component**
GO:0005832 chaperonin-containing T-complex
IBA
GO_REF:0000033
ACCEPT
Summary: CCT5 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 CCT5; 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: CCT5 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: CCT5 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: CCT5 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: CCT5 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: CCT5 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: CCT5 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: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: CCT5 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
IPI
PMID:15704212
Physiological effects of unassembled chaperonin Cct subunits...
ACCEPT
Summary: CCT5 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:0005832 chaperonin-containing T-complex
IDA
PMID:16762366
Quantitative actin folding reactions using yeast CCT purifie...
ACCEPT
Summary: CCT5 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:15704212
Eukaryotic chaperonins, the Cct complexes, are assembled into two rings, each of which is composed of a stoichiometric array of eight different subunits
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

CCT5 is the epsilon 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
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"
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 CCT5 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"
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/CCT5/CCT5-deep-research-falcon.md
Falcon deep research report for CCT5
  • The Falcon report was reviewed and synthesized into the CCT5 curation, including core-function framing, family/PANTHER context, and evidence limitations.

Suggested Questions for Experts

Q: How does the high-ATP-affinity Cct5 subunit shape client progression through the yeast TRiC/CCT ATPase cycle?

Suggested Experiments

Experiment: Compare ATPase-cycle reporters, client folding assays, and viability for targeted CCT5 ATP-pocket alleles in yeast, separating assembled-complex abundance from kinetic effects.

Hypothesis: Cct5 ATP binding/hydrolysis helps set the timing of TRiC/CCT chamber closure for actin and tubulin clients.

Type: site-directed mutagenesis with chaperonin folding and ATPase assays

πŸ“š Additional Documentation

Deep Research Falcon

(CCT5-deep-research-falcon.md)

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gene_id: CCT5
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uniprot_accession: P40413
protein_description: 'RecName: Full=T-complex protein 1 subunit epsilon; Short=TCP-1-epsilon;
AltName: Full=CCT-epsilon;'
gene_info: Name=CCT5; Synonyms=TCP5; OrderedLocusNames=YJR064W; ORFNames=J1752;
organism_full: Saccharomyces cerevisiae (strain ATCC 204508 / S288c) (Baker's yeast).
protein_family: Belongs to the TCP-1 chaperonin family. .
protein_domains: Chap_CCT_epsi. (IPR012718); 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: P40413
  • Protein Description: RecName: Full=T-complex protein 1 subunit epsilon; Short=TCP-1-epsilon; AltName: Full=CCT-epsilon;
  • Gene Information: Name=CCT5; Synonyms=TCP5; OrderedLocusNames=YJR064W; ORFNames=J1752;
  • Organism (full): Saccharomyces cerevisiae (strain ATCC 204508 / S288c) (Baker's yeast).
  • Protein Family: Belongs to the TCP-1 chaperonin family. .
  • Key Domains: Chap_CCT_epsi. (IPR012718); 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 "CCT5" 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 'CCT5' 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 CCT5 (gene ID: CCT5, UniProt: P40413) 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: P40413
  • Protein Description: RecName: Full=T-complex protein 1 subunit epsilon; Short=TCP-1-epsilon; AltName: Full=CCT-epsilon;
  • Gene Information: Name=CCT5; Synonyms=TCP5; OrderedLocusNames=YJR064W; ORFNames=J1752;
  • Organism (full): Saccharomyces cerevisiae (strain ATCC 204508 / S288c) (Baker's yeast).
  • Protein Family: Belongs to the TCP-1 chaperonin family. .
  • Key Domains: Chap_CCT_epsi. (IPR012718); 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 "CCT5" 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 'CCT5' 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 CCT5 (gene ID: CCT5, UniProt: P40413) 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: Functional Annotation of CCT5 (UniProt P40413) in Saccharomyces cerevisiae (S288c)

Executive summary

CCT5 (ORF YJR064W, synonym TCP5) encodes the epsilon subunit of the cytosolic group II chaperonin TRiC/CCT (also called the TCP‑1 ring complex). CCT5 is not an enzyme with a unique small-molecule substrate; rather, it is an ATP-binding/ATPase chaperonin subunit that contributes to an essential hetero-oligomeric folding machine that supports eukaryotic proteostasis, with strongest evidence for folding/biogenesis of actin and tubulin and for broad roles in assembly of WD40/propeller proteins and other complexes. Yeast genetic and structural studies implicate ATPase-competent CCT5 as critical for viability and for the ATP-driven conformational cycle of the TRiC/CCT chamber. Recent 2023–2024 cryo-EM work in the field (mostly in mammalian TRiC, plus yeast mechanistic cryo-EM studies) refined models for how the ATPase cycle drives substrate translocation and how co-chaperones (prefoldin, phosducin-like proteins) control substrate delivery and chamber occupancyβ€”mechanistic context directly relevant to interpreting yeast CCT5’s function as part of TRiC/CCT. (stoldt1996reviewthecct pages 1-2, grantham2020themolecularchaperone pages 1-2, kelly2020structuralandfunctionala pages 42-48, liu2023pathwayandmechanism pages 1-2, junsun2024astructuralvista pages 1-2)

1. Target verification (critical identity disambiguation)

1.1 Verified gene/protein identity

The literature and yeast-specific reviews identify the S. cerevisiae epsilon subunit of the CCT/TRiC chaperonin as CCT5 (historical names include CctΞ΅, TCP1E/TCP5) and explicitly map it to ORF YJR064W in S288c. (Publication date: 1996-05; URL: https://doi.org/10.1002/(sici)1097-0061(199605)12:6<523::aid-yea962>3.0.co;2-c) (stoldt1996reviewthecct pages 1-2)

1.2 Avoiding symbol ambiguity

The symbol CCT5 is also used for orthologous TRiC/CCT subunit 5 proteins in animals, where variants are associated with disease (e.g., hereditary sensory neuropathy). Such papers inform conserved structure/function of CCT5-family proteins but are not yeast-specific functional genetics and should not be conflated with S. cerevisiae phenotypes. (pereira2017structureofthe pages 1-2, kelly2020structuralandfunctionala pages 23-28)

2. Key concepts and definitions (current understanding)

2.1 TRiC/CCT: a eukaryotic group II chaperonin

TRiC/CCT is a group II chaperonin localized to the eukaryotic cytosol, consisting of two stacked rings with eight distinct paralogous subunits per ring (CCT1–CCT8; CCT5 is the epsilon/β€œsubunit 5” paralog). The complex couples ATP binding/hydrolysis to large conformational changes that close a built-in lid over a central folding cavity (unlike bacterial GroEL, which requires GroES). (ghozlan2022thetrickybusiness pages 1-2, kabir2011functionalsubunitsof pages 1-2, kelly2020structuralandfunctionala pages 14-18)

2.2 What CCT5 β€œdoes” at the molecular level

CCT5 is best defined as a structural and catalytic component (ATPase + substrate-interaction surface) of TRiC/CCT rather than a standalone enzyme. TRiC/CCT’s strongest obligate substrates are actin and tubulin, which require TRiC/CCT to reach native conformations/assembly-competent states; CCT5 contributes one of the eight distinct apical-domain surfaces that form the composite substrate-binding environment within the chamber. (grantham2020themolecularchaperone pages 1-2, willison2018thesubstratespecificity pages 1-2)

2.3 Conserved domain architecture

CCT5-family subunits have a canonical chaperonin architecture with equatorial (ATP binding and ring contacts), intermediate (hinge/transmission), and apical (substrate recognition/lid) domains. The ATP-binding region is relatively conserved across paralogs, whereas apical domains are more divergent and contribute to subunit-specific substrate recognition properties. (ghozlan2022thetrickybusiness pages 1-2, pereira2017structureofthe pages 1-2)

3. Yeast-specific functional annotation of CCT5

3.1 Complex membership, subunit arrangement, and chamber electrostatics

Yeast TRiC/CCT structural work places subunits in a defined ring order and groups them into electrostatic β€œhemispheres” within the chamber; CCT5 sits in the CCT2 hemisphere alongside CCT4 and CCT2, contributing to a positively charged partition of the folding environment. (kelly2020structuralandfunctional pages 35-42)

3.2 ATPase asymmetry and subunit-specific conformational role of CCT5

In yeast structural/functional analyses, CCT5 belongs to a high ATP-affinity set of subunits (CCT1/2/4/5), with CCT5 (and CCT4) described as having the highest ATP affinities in one model. CCT5’s apical domain undergoes substantial nucleotide-linked motion (reported as ~14Β° rotation toward the folding cavity upon nucleotide binding), and CCT5 is among the subunits showing larger conformational changes than others in the ring. (kelly2020structuralandfunctionala pages 42-48)

3.3 Essentiality and viability-relevant mutations

Yeast-focused synthesis indicates that all eight CCT genes are essential and that even relatively small perturbations in ATP-binding motifs/ATPase kinetics can cause severe growth and morphology defects. (willison2018thesubstratespecificity pages 2-3)

More directly subunit-linked evidence indicates that mutating the P-loop ATP-binding motif (GDGTT→AAAAA) in high-affinity subunits leads to lethal phenotypes in yeast, implicating ATPase competence of high-affinity subunits including CCT5 as critical for viability. (kelly2020structuralandfunctionala pages 42-48)

3.4 Biological processes and pathway context inferred from yeast CCT/TRiC biology

Because CCT5 functions as an obligate TRiC/CCT subunit, yeast process annotations are best supported at the complex level:

  • Actin and microtubule assembly / cytoskeletal organization: Yeast conditional mutant studies link the Cct complex to in vivo assembly of microtubules and actin, consistent with conserved TRiC/CCT roles in actin and tubulin folding. (1996-05; URL above) (stoldt1996reviewthecct pages 1-2)
  • Genetic interactions with cytoskeletal alleles: Allele-specific synthetic interactions between CCT subunit mutants and actin/tubulin alleles (e.g., inviability of a cct1-1 tub2-402 double mutant) support close functional coupling between CCT and cytoskeletal components. (stoldt1996reviewthecct pages 5-6)
  • Cell cycle regulation via folding of APC/C activators: A yeast CCT interactome/functional synthesis indicates that WD40/propeller proteins and specific cell-cycle regulators such as APC activators Cdc20p and Cdh1p are obligate CCT substrates in yeast. (willison2018thesubstratespecificity pages 1-2)
  • Growth/nutrient signaling linkage (TOR pathway): Expert synthesis highlights TRiC/CCT’s functional linkage to TOR signaling in yeast, including growth defects when CCT activity is reduced and altered phosphorylation of TOR pathway outputs (S6K/S6). (kelly2020structuralandfunctionalb pages 23-28)

3.5 Subcellular localization

CCT5 acts primarily in the cytosol as part of the cytosolic TRiC/CCT folding machine. Current evidence in the retrieved set supports this cytosolic role; no strong evidence was retrieved for a stable organellar or secreted localization for yeast CCT5. (kabir2011functionalsubunitsof pages 1-2, kelly2020structuralandfunctionala pages 14-18)

4. Recent developments (prioritizing 2023–2024)

Recent high-resolution structural and mechanistic work has focused on TRiC/CCT’s ATP-driven cycle and co-chaperone coordination; while much of this is performed on mammalian TRiC, the mechanisms are widely treated as conserved and provide direct interpretive context for yeast subunit roles (including CCT5).

4.1 2023: Cryo-EM delineation of tubulin folding pathway along the ATPase cycle

A 2023 cryo-EM + XL-MS study captured multiple TRiC states with endogenously engaged tubulin and quantified state occupancies. Key reported quantitative findings include open-state classification with 61.6% empty and 38.4% tubulin-like density, and a trapped population with 27.2% both-rings-closed under ATP-AlFx. The work describes gradual substrate translocation/stabilization during ring closure and a near-native tubulin captured in the closed chamber; notably, the tubulin I domain is reported to associate more loosely with the CCT2 hemisphere subunits (CCT7/5/2/4)β€”the same hemisphere that includes yeast CCT5. (Publication date: 2023-05; URL: https://doi.org/10.1038/s42003-023-04915-x) (liu2023pathwayandmechanism pages 1-2, liu2023pathwayandmechanism pages 6-7)

4.2 2024: Structural mechanism for PhLP2A–TRiC coordination and prefoldin displacement

A 2024 Nature Communications cryo-EM/biochemical study resolved how PhLP2A binds open TRiC, how an N-terminal helix engages CCT3/CCT4 apical domains to displace prefoldin, and how ATP-induced closure rearranges PhLP2A contacts. The authors reiterate that TRiC facilitates folding of ~10% of the eukaryotic proteome and show a mechanistic model in which co-chaperones and substrates can segregate into opposing chambers during the folding cycle. (Publication date: 2024-02; URL: https://doi.org/10.1038/s41467-024-45242-x) (junsun2024astructuralvista pages 1-2)

Visual evidence: the paper includes a labeled cryo-EM view of the TRiC ring with subunits CCT1–CCT8 annotated, supporting the defined subunit arrangement that underpins any subunit-specific annotation. (junsun2024astructuralvista media 0880aeaf)

4.3 Yeast-focused mechanistic cryo-EM: ring opening intermediates (context)

A yeast TRiC cryo-EM study of ADP-bound ensembles reports a stepwise ring-opening model in which outward leaning involves consecutive subunits including CCT6/8/7/5, placing CCT5 on a mechanically relevant trajectory during nucleotide-dependent reopening and (putative) substrate release. (Publication: 2025; URL: https://doi.org/10.1017/qrd.2024.17) (jin2025theconformationallandscape pages 1-2)

5. Current applications and real-world implementations

Although yeast CCT5 itself is primarily a basic-science target, TRiC/CCT research has translational applications; yeast is often the model for mechanistic/functional dissection.

5.1 Therapeutic targeting and chemical modulation of TRiC/CCT

Expert syntheses describe TRiC/CCT as a potential therapeutic target in cancer and proteostasis-related diseases. Examples discussed include a TRiC-inhibiting peptide (CT20p) tested in cancer cell line contexts and small molecules/lipids reported to modulate TRiC-mediated folding (e.g., clemastine; 1-deoxydihydroceramide), as well as modulation by stress-response-linked factors (e.g., HSF1A). These applications are complex-level rather than yeast-CCT5-specific but rely on understanding subunit-specific assembly/ATPase features (including those involving CCT5). (kelly2020structuralandfunctionala pages 23-28, shen2025proteinfoldingby pages 5-7)

5.2 Proteostasis engineering and mechanistic tool development in yeast

Yeast serves as an engineering and discovery platform for TRiC/CCT structure-function studies, including strategies for subunit identification in cryo-EM maps by endogenous tagging approaches. Such methods enable subunit-resolved mechanistic annotation of components like CCT5 without overexpression artifacts. (Publication date: 2018-02; URL: https://doi.org/10.1038/s41598-017-18962-y) (context: subunit identification strategy applied to TRiC; CCT5 used as tagged subunit) (from retrieved paper list; not directly evidenced in snippets beyond abstract)

6. Statistics and quantitative data relevant to yeast CCT5 annotation

  • Proteome fraction: TRiC/CCT is widely described as folding roughly ~10% of cytosolic proteins. (junsun2024astructuralvista pages 1-2, liu2023pathwayandmechanism pages 1-2)
  • Yeast transcript estimate for CCT5: A yeast-focused synthesis reports an estimated CCT5 mRNA copy number ~2.24 per cell (derived from global transcript counts at 30Β°C) and notes low variance among CCT subunits in abundance. (Publication date: 2018-06; URL: https://doi.org/10.1098/rstb.2017.0192) (willison2018thesubstratespecificity pages 7-8)
  • Yeast interactome scale: The yeast CCT interactome is summarized as roughly ~300 members, with many being cofactors/effectors rather than direct folding substrates, indicating extensive pathway connectivity beyond actin/tubulin. (willison2018thesubstratespecificity pages 2-3)

7. Interpretation and expert analysis (what is well-supported vs. uncertain for yeast CCT5)

7.1 High-confidence statements (supported directly)

  • CCT5 is the S. cerevisiae TRiC/CCT epsilon subunit encoded by YJR064W. (stoldt1996reviewthecct pages 1-2)
  • CCT5 participates in a cytosolic group II chaperonin complex essential for folding/biogenesis of actin and tubulin (complex-level function with strong yeast linkage). (stoldt1996reviewthecct pages 1-2, willison2018thesubstratespecificity pages 1-2)
  • Yeast structural/functional analyses place CCT5 in a high ATP-affinity hemisphere and show large nucleotide-linked conformational change; yeast viability depends on ATPase-competent high-affinity subunits including CCT5 (P-loop mutant lethality). (kelly2020structuralandfunctionala pages 42-48)

7.2 Medium-confidence/inference statements

  • Subunit-specific substrate recognition: Reviews emphasize that divergence in apical domains across the eight subunits confers substrate selectivity, implying that CCT5 contributes unique binding determinants. However, the retrieved yeast literature did not provide a CCT5-only substrate list; most substrate specificity is attributed to the assembled chamber interface. (willison2018thesubstratespecificity pages 1-2, ghozlan2022thetrickybusiness pages 1-2)

7.3 Not resolved in the retrieved corpus

  • A dedicated, yeast-only experimental characterization of CCT5-specific phenotypes (e.g., temperature-sensitive cct5 alleles) was not retrieved here; available yeast phenotypes in the evidence largely pertain to the TRiC/CCT complex broadly or to other subunits. Accordingly, CCT5-specific phenotype statements above are restricted to ATP-binding motif perturbations and subunit-resolved structural dynamics. (kelly2020structuralandfunctionala pages 42-48, willison2018thesubstratespecificity pages 2-3)

Summary table

Topic Key points Best recent/authoritative source (with year) Evidence/notes
Target identity verification CCT5 in this report refers to the Saccharomyces cerevisiae gene/product encoded by ORF YJR064W; it is the T-complex protein 1 subunit epsilon (CCT/TRiC subunit Ξ΅), also called TCP5/TCP1E/CctΞ΅ in older nomenclature. Stoldt et al., Yeast (1996); Grantham, Front. Genet. (2020) Yeast review explicitly maps the epsilon subunit to YJR064W and lists historical synonyms; later reviews place CCT5 among the eight paralogous CCT/TRiC subunits, helping distinguish it from metazoan CCT5 orthologs with disease literature that should not be conflated with yeast annotation. (stoldt1996reviewthecct pages 1-2, grantham2020themolecularchaperone pages 1-2)
Complex membership CCT5 is one of the 8 distinct subunits per ring of the eukaryotic group II cytosolic chaperonin TRiC/CCT, forming a double-ring complex. In yeast structural work, subunits occupy a defined order within each ring. Jin et al., Subcell. Biochem. (2020); Kelly (2020) Reviews and structural studies agree that TRiC/CCT is a hetero-oligomeric, barrel-shaped chaperonin with two stacked rings; yeast cryo-EM resolves a defined subunit order and places CCT5 in the ring architecture rather than as a standalone enzyme. (kelly2020structuralandfunctionala pages 14-18, kelly2020structuralandfunctional pages 35-42)
Protein family / definition CCT5 belongs to the TCP-1/CCT chaperonin family, i.e. group II chaperonins specialized for ATP-dependent folding of difficult cytosolic proteins in eukaryotes. Ghozlan et al., Front. Cell Dev. Biol. (2022); Kabir et al. (2011) Family-level features match UniProt/domain expectations: eukaryotic cytosolic localization, ATP-dependent conformational cycle, and function within the hetero-oligomeric CCT machine. (ghozlan2022thetrickybusiness pages 1-2, kabir2011functionalsubunitsof pages 1-2)
Domain architecture Like other CCT subunits, CCT5 has the canonical three-domain chaperonin architecture: equatorial domain (ATP binding, ring contacts), intermediate domain (hinge/transmission), and apical domain (substrate/lid functions). Pereira et al., Sci. Rep. (2017); Kelly (2020) These structural features are conserved across CCT5 orthologs and are consistent with the supplied InterPro/domain annotations. The equatorial ATP-binding region is the most conserved; the apical region contributes to subunit-specific substrate recognition. (pereira2017structureofthe pages 1-2, kelly2020structuralandfunctionala pages 14-18)
Cellular localization The biologically relevant localization of CCT5 is cytosolic, as a constituent of the cytosolic TRiC/CCT chaperonin. Kabir et al. (2011); Ghozlan et al. (2022) Available evidence supports cytosolic localization at the complex level; no strong evidence from the retrieved set supports a stable extracellular or organellar role for yeast CCT5. (kabir2011functionalsubunitsof pages 1-2, ghozlan2022thetrickybusiness pages 1-2)
Primary molecular function CCT5 is not a classical metabolic enzyme with a unique small-molecule substrate; instead, it contributes one ATPase/substrate-binding module to the ATP-driven folding chamber of TRiC/CCT. Its function is to help fold cytosolic proteins and maintain proteostasis. Grantham, Front. Genet. (2020); Ghozlan et al., Front. Cell Dev. Biol. (2022) Reviews emphasize that TRiC/CCT folds obligate clients such as actin and tubulin, and likely assists a restricted but important set of additional proteins; CCT5 contributes to this machine as a structurally specialized subunit. (grantham2020themolecularchaperone pages 1-2, ghozlan2022thetrickybusiness pages 1-2)
Core substrates / pathway context At the complex level, TRiC/CCT is best established for folding actin and tubulin and participates more broadly in cytosolic proteostasis, including assembly/folding of some complex or aggregation-prone proteins. Stoldt et al., Yeast (1996); Willison, Phil. Trans. R. Soc. B (2018) Yeast and broader eukaryotic studies converge on actin/tubulin as canonical obligate clients. For yeast CCT5 specifically, evidence is mostly subunit-in-complex rather than substrate specificity assigned to the isolated subunit. (stoldt1996reviewthecct pages 2-4, stoldt1996reviewthecct pages 1-2, willison2018thesubstratespecificity pages 7-8)
Yeast-specific biological processes In yeast, the Cct complex is required for microtubule and actin assembly/organization, linking CCT5 indirectly to cytoskeletal biogenesis, cell growth, and proteostasis. Stoldt et al., Yeast (1996) Conditional-mutant studies in S. cerevisiae showed Cct requirement for in vivo assembly of microtubules and actin; the excerpted evidence is stronger for the complex than for CCT5 alone. (stoldt1996reviewthecct pages 2-4, stoldt1996reviewthecct pages 1-2)
Subunit-specific structural role of CCT5 Yeast cryo-EM and biochemical analyses identify CCT5 as a high-ATP-affinity subunit whose apical domain undergoes substantial nucleotide-linked movement; it contributes to the positively charged CCT2 hemisphere of the chamber. Kelly (2020) CCT5 shows ~14Β° apical-domain rotation on nucleotide binding and is grouped among subunits with larger conformational changes; CCT5/CCT4 are highlighted as having the highest ATP affinities in one yeast analysis. (kelly2020structuralandfunctional pages 42-48, kelly2020structuralandfunctionala pages 42-48, kelly2020structuralandfunctional pages 35-42)
Essentiality / genetic evidence in yeast The overall CCT machine is essential, and reviews note that the eight subunits are products of essential genes in yeast; yeast mutational data further show that disrupting ATP-binding P-loop residues in high-affinity subunits, including CCT5, is lethal. Grantham, Front. Genet. (2020); Kelly (2020) The strongest retrieved CCT5-specific genetic statement is that alanine substitution of the P-loop motif in high-affinity subunits causes lethal phenotypes in yeast, implicating CCT5 ATPase competence in viability. (grantham2020themolecularchaperone pages 1-2, kelly2020structuralandfunctional pages 42-48, kelly2020structuralandfunctionala pages 42-48)
Assembly importance Evidence from structural/biochemical work suggests CCT5 may be particularly important for TRiC assembly, though this is not yet a universally canonical annotation in basic yeast databases. Kelly (2020) The retrieved structural dissertation/review material explicitly states that analyses suggested CCT5 is the most important subunit for assembly of TRiC; this is best treated as a strong mechanistic proposal rather than settled textbook fact. (kelly2020structuralandfunctionalb pages 23-28)
Quantitative/statistical data CCT/TRiC is estimated to assist folding of roughly ~10% of cytosolic proteins. In one yeast-focused synthesis, CCT5 mRNA abundance was estimated at about 2.24 copies/cell, and CCT subunits showed low variance in abundance across the complex. Park et al., Nat. Commun. (2024) for ~10%; Willison, Phil. Trans. R. Soc. B (2018) for yeast abundance synthesis The ~10% figure is widely repeated across structural reviews. The yeast quantitative synthesis indicates coordinated expression of CCT subunits and places actin/tubulin/CCT near central abundance and half-life distributions. (junsun2024astructuralvista pages 1-2, liu2023pathwayandmechanism pages 1-2, willison2018thesubstratespecificity pages 7-8)
Co-chaperone network TRiC/CCT functions with prefoldin (PFD) and phosducin-like proteins (PhLPs); these co-chaperones help deliver or stabilize substrates and regulate the folding cycle. Gestaut et al., Cell (2019); Park et al., Nat. Commun. (2024) This network is directly relevant to functional annotation because CCT5 acts within a multi-component folding pathway rather than alone. Disruption of PFD–TRiC interaction causes widespread aggregation in yeast, illustrating pathway-level importance. (junsun2024astructuralvista pages 1-2, kelly2020structuralandfunctionalb pages 23-28, kelly2020structuralandfunctionala pages 23-28)
2023 development: substrate-folding mechanism Recent cryo-EM work mapped the ATPase-cycle-dependent pathway of tubulin folding by TRiC/CCT, showing gradual substrate translocation/stabilization and a near-native tubulin state in the closed chamber. Liu et al., Commun. Biol. (2023) Quantitative details include open-state classes with 61.6% empty and 38.4% tubulin-like density, a 3.1 Γ… open-state map, and 27.2% both-rings-closed population under ATP-AlFx conditions. Though from human TRiC, these findings strongly inform conserved mechanism relevant to yeast CCT5 annotation. (liu2023pathwayandmechanism pages 6-7, liu2023pathwayandmechanism pages 1-2)
2024 development: co-chaperone mechanism New structural work resolved how PhLP2A and prefoldin interact with open/closed TRiC and showed ATP-driven rearrangements that coordinate substrate handling. Park et al., Nat. Commun. (2024) PhLP2A binds open TRiC through polyvalent contacts, can displace PFD via CCT3/4 contacts, and rearranges during closure; these studies refine current understanding of how subunits such as CCT5 participate in a regulated cochaperone-assisted folding cycle. (junsun2024astructuralvista pages 1-2, junsun2024astructuralvista media 0880aeaf)
Expert interpretation / real-world relevance Authoritative reviews frame TRiC/CCT as a central proteostasis hub and a candidate therapeutic target in aggregation diseases, cancer, and viral infection. Yeast remains an important mechanistic model for defining subunit function and proteostasis defects. Ghozlan et al. (2022); Grantham (2020); Shen & Willardson (2025) These application-oriented insights are mostly complex-level rather than yeast-CCT5-specific, but they explain why subunit-resolved annotation matters: altered CCT subunits affect assembly, substrate folding, and disease-linked proteostasis pathways. (grantham2020themolecularchaperone pages 1-2, ghozlan2022thetrickybusiness pages 1-2, shen2025proteinfoldingby pages 5-7)

Table: This table summarizes verified identity, function, localization, and mechanistic evidence for Saccharomyces cerevisiae CCT5/YJR064W, emphasizing what is directly supported for the yeast subunit versus what is inferred from the TRiC/CCT complex. It also highlights recent 2023-2024 developments that refine the current mechanistic annotation of CCT5 within TRiC.

Key figures (visual evidence)

  • Labeled TRiC subunit arrangement and PhLP2A-bound open-state structure (useful for orienting where CCT5 sits in the ring and how cochaperones engage the complex). (junsun2024astructuralvista media 0880aeaf)
  • Comparative schematics of prefoldin and PhLP2A interactions with TRiC (relevant to understanding co-chaperone regulated folding pathways). (junsun2024astructuralvista media 774d2963, junsun2024astructuralvista media e727d38e)

References (URLs and publication dates from evidence)

  • Stoldt V. et al. β€œReview: The Cct eukaryotic chaperonin subunits of Saccharomyces cerevisiae and other yeasts.” Yeast 1996-05. https://doi.org/10.1002/(sici)1097-0061(199605)12:6<523::aid-yea962>3.0.co;2-c (stoldt1996reviewthecct pages 1-2)
  • Willison K.R. β€œThe substrate specificity of eukaryotic cytosolic chaperonin CCT.” Phil. Trans. R. Soc. B 2018-06. https://doi.org/10.1098/rstb.2017.0192 (willison2018thesubstratespecificity pages 7-8, willison2018thesubstratespecificity pages 2-3, willison2018thesubstratespecificity pages 1-2)
  • Grantham J. β€œThe Molecular Chaperone CCT/TRiC: An Essential Component of Proteostasis and a Potential Modulator of Protein Aggregation.” Front. Genet. 2020-03. https://doi.org/10.3389/fgene.2020.00172 (grantham2020themolecularchaperone pages 1-2)
  • Liu C. et al. β€œPathway and mechanism of tubulin folding mediated by TRiC/CCT along its ATPase cycle revealed using cryo-EM.” Communications Biology 2023-05. https://doi.org/10.1038/s42003-023-04915-x (liu2023pathwayandmechanism pages 1-2, liu2023pathwayandmechanism pages 6-7)
  • Park J. et al. β€œA structural vista of phosducin-like PhLP2A–chaperonin TRiC cooperation during the ATP-driven folding cycle.” Nature Communications 2024-02. https://doi.org/10.1038/s41467-024-45242-x (junsun2024astructuralvista pages 1-2, junsun2024astructuralvista media 0880aeaf)

References

  1. (stoldt1996reviewthecct pages 1-2): Volker Stoldt, Felicitas Rademacher, Verena Kehren, Joachim F. Ernst, David A. Pearce, and Fred Sherman. Review: the cct eukaryotic chaperonin subunits of saccharomyces cerevisiae and other yeasts. Yeast, 12:523-529, May 1996. URL: https://doi.org/10.1002/(sici)1097-0061(199605)12:6<523::aid-yea962>3.0.co;2-c, doi:10.1002/(sici)1097-0061(199605)12:6<523::aid-yea962>3.0.co;2-c. This article has 153 citations and is from a peer-reviewed journal.

  2. (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.

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

  4. (liu2023pathwayandmechanism pages 1-2): Caixuan Liu, Mingliang Jin, Shutian Wang, Wenyu Han, Qiaoyu Zhao, Yifan Wang, Cong Xu, Lei Diao, Yue Yin, Chao Peng, Lan Bao, Yanxing Wang, and Yao Cong. Pathway and mechanism of tubulin folding mediated by tric/cct along its atpase cycle revealed using cryo-em. Communications Biology, May 2023. URL: https://doi.org/10.1038/s42003-023-04915-x, doi:10.1038/s42003-023-04915-x. This article has 28 citations and is from a peer-reviewed journal.

  5. (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.

  6. (pereira2017structureofthe pages 1-2): Jose H. Pereira, Ryan P. McAndrew, Oksana A. Sergeeva, Corie Y. Ralston, Jonathan A. King, and Paul D. Adams. Structure of the human tric/cct subunit 5 associated with hereditary sensory neuropathy. Scientific Reports, Jun 2017. URL: https://doi.org/10.1038/s41598-017-03825-3, doi:10.1038/s41598-017-03825-3. This article has 43 citations and is from a peer-reviewed journal.

  7. (kelly2020structuralandfunctionala pages 23-28): J Kelly. Structural and functional characterisation of the group ii chaperonin cct/tric. Unknown journal, 2020.

  8. (ghozlan2022thetrickybusiness pages 1-2): Heba Ghozlan, Amanda Cox, Daniel Nierenberg, Stephen King, and Annette R. Khaled. The tricky business of protein folding in health and disease. Frontiers in Cell and Developmental Biology, May 2022. URL: https://doi.org/10.3389/fcell.2022.906530, doi:10.3389/fcell.2022.906530. This article has 34 citations.

  9. (kabir2011functionalsubunitsof pages 1-2): M. Anaul Kabir, Wasim Uddin, Aswathy Narayanan, Praveen Kumar Reddy, M. Aman Jairajpuri, Fred Sherman, and Zulfiqar Ahmad. Functional subunits of eukaryotic chaperonin cct/tric in protein folding. Journal of Amino Acids, 2011:1-16, Jul 2011. URL: https://doi.org/10.4061/2011/843206, doi:10.4061/2011/843206. This article has 62 citations.

  10. (kelly2020structuralandfunctionala pages 14-18): J Kelly. Structural and functional characterisation of the group ii chaperonin cct/tric. Unknown journal, 2020.

  11. (willison2018thesubstratespecificity pages 1-2): Keith R. Willison. The substrate specificity of eukaryotic cytosolic chaperonin cct. Philosophical Transactions of the Royal Society B: Biological Sciences, 373:20170192, Jun 2018. URL: https://doi.org/10.1098/rstb.2017.0192, doi:10.1098/rstb.2017.0192. This article has 75 citations and is from a domain leading peer-reviewed journal.

  12. (kelly2020structuralandfunctional pages 35-42): J Kelly. Structural and functional characterisation of the group ii chaperonin cct/tric. Unknown journal, 2020.

  13. (willison2018thesubstratespecificity pages 2-3): Keith R. Willison. The substrate specificity of eukaryotic cytosolic chaperonin cct. Philosophical Transactions of the Royal Society B: Biological Sciences, 373:20170192, Jun 2018. URL: https://doi.org/10.1098/rstb.2017.0192, doi:10.1098/rstb.2017.0192. This article has 75 citations and is from a domain leading peer-reviewed journal.

  14. (stoldt1996reviewthecct pages 5-6): Volker Stoldt, Felicitas Rademacher, Verena Kehren, Joachim F. Ernst, David A. Pearce, and Fred Sherman. Review: the cct eukaryotic chaperonin subunits of saccharomyces cerevisiae and other yeasts. Yeast, 12:523-529, May 1996. URL: https://doi.org/10.1002/(sici)1097-0061(199605)12:6<523::aid-yea962>3.0.co;2-c, doi:10.1002/(sici)1097-0061(199605)12:6<523::aid-yea962>3.0.co;2-c. This article has 153 citations and is from a peer-reviewed journal.

  15. (kelly2020structuralandfunctionalb pages 23-28): J Kelly. Structural and functional characterisation of the group ii chaperonin cct/tric. Unknown journal, 2020.

  16. (liu2023pathwayandmechanism pages 6-7): Caixuan Liu, Mingliang Jin, Shutian Wang, Wenyu Han, Qiaoyu Zhao, Yifan Wang, Cong Xu, Lei Diao, Yue Yin, Chao Peng, Lan Bao, Yanxing Wang, and Yao Cong. Pathway and mechanism of tubulin folding mediated by tric/cct along its atpase cycle revealed using cryo-em. Communications Biology, May 2023. URL: https://doi.org/10.1038/s42003-023-04915-x, doi:10.1038/s42003-023-04915-x. This article has 28 citations and is from a peer-reviewed journal.

  17. (junsun2024astructuralvista media 0880aeaf): 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.

  18. (jin2025theconformationallandscape pages 1-2): Mingliang Jin, Yunxiang Zang, Huping Wang, and Yao Cong. The conformational landscape of tric ring-opening and its underlying stepwise mechanism revealed by cryo-em. QRB Discovery, Dec 2025. URL: https://doi.org/10.1017/qrd.2024.17, doi:10.1017/qrd.2024.17. This article has 3 citations.

  19. (shen2025proteinfoldingby pages 5-7): Peter S. Shen and Barry M. Willardson. Protein folding by the cct/tric chaperone complex. Current Opinion in Structural Biology, 91:102999, Apr 2025. URL: https://doi.org/10.1016/j.sbi.2025.102999, doi:10.1016/j.sbi.2025.102999. This article has 10 citations and is from a peer-reviewed journal.

  20. (willison2018thesubstratespecificity pages 7-8): Keith R. Willison. The substrate specificity of eukaryotic cytosolic chaperonin cct. Philosophical Transactions of the Royal Society B: Biological Sciences, 373:20170192, Jun 2018. URL: https://doi.org/10.1098/rstb.2017.0192, doi:10.1098/rstb.2017.0192. This article has 75 citations and is from a domain leading peer-reviewed journal.

  21. (stoldt1996reviewthecct pages 2-4): Volker Stoldt, Felicitas Rademacher, Verena Kehren, Joachim F. Ernst, David A. Pearce, and Fred Sherman. Review: the cct eukaryotic chaperonin subunits of saccharomyces cerevisiae and other yeasts. Yeast, 12:523-529, May 1996. URL: https://doi.org/10.1002/(sici)1097-0061(199605)12:6<523::aid-yea962>3.0.co;2-c, doi:10.1002/(sici)1097-0061(199605)12:6<523::aid-yea962>3.0.co;2-c. This article has 153 citations and is from a peer-reviewed journal.

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

  23. (junsun2024astructuralvista media 774d2963): 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.

  24. (junsun2024astructuralvista media e727d38e): 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. stoldt1996reviewthecct pages 1-2
  2. kelly2020structuralandfunctional pages 35-42
  3. kelly2020structuralandfunctionala pages 42-48
  4. willison2018thesubstratespecificity pages 2-3
  5. stoldt1996reviewthecct pages 5-6
  6. willison2018thesubstratespecificity pages 1-2
  7. kelly2020structuralandfunctionalb pages 23-28
  8. junsun2024astructuralvista pages 1-2
  9. jin2025theconformationallandscape pages 1-2
  10. willison2018thesubstratespecificity pages 7-8
  11. grantham2020themolecularchaperone pages 1-2
  12. liu2023pathwayandmechanism pages 1-2
  13. pereira2017structureofthe pages 1-2
  14. kelly2020structuralandfunctionala pages 23-28
  15. ghozlan2022thetrickybusiness pages 1-2
  16. kabir2011functionalsubunitsof pages 1-2
  17. kelly2020structuralandfunctionala pages 14-18
  18. liu2023pathwayandmechanism pages 6-7
  19. shen2025proteinfoldingby pages 5-7
  20. stoldt1996reviewthecct pages 2-4
  21. kelly2020structuralandfunctional pages 42-48
  22. https://doi.org/10.1002/(sici
  23. https://doi.org/10.1038/s42003-023-04915-x
  24. https://doi.org/10.1038/s41467-024-45242-x
  25. https://doi.org/10.1017/qrd.2024.17
  26. https://doi.org/10.1038/s41598-017-18962-y
  27. https://doi.org/10.1098/rstb.2017.0192
  28. https://doi.org/10.3389/fgene.2020.00172
  29. https://doi.org/10.3389/fgene.2020.00172,
  30. https://doi.org/10.1038/s42003-023-04915-x,
  31. https://doi.org/10.1038/s41467-024-45242-x,
  32. https://doi.org/10.1038/s41598-017-03825-3,
  33. https://doi.org/10.3389/fcell.2022.906530,
  34. https://doi.org/10.4061/2011/843206,
  35. https://doi.org/10.1098/rstb.2017.0192,
  36. https://doi.org/10.1017/qrd.2024.17,
  37. https://doi.org/10.1016/j.sbi.2025.102999,

πŸ“„ View Raw YAML

id: P40413
gene_symbol: CCT5
product_type: PROTEIN
status: COMPLETE
taxon:
  id: NCBITaxon:559292
  label: Saccharomyces cerevisiae
description: >-
  CCT5 encodes the epsilon subunit of the cytosolic group II chaperonin TRiC/CCT. Cct5 is an obligate
  subunit of the ATP-driven double-ring folding machine, contributes one ATPase/substrate-contact module
  to the chamber, and is best curated as part of the complex that folds actin, tubulin, and other cytosolic
  clients. The subunit-specific literature emphasizes ATP-cycle asymmetry and chamber architecture rather
  than a separate standalone activity.
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: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: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 CCT5 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: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/CCT5/CCT5-deep-research-falcon.md
  title: Falcon deep research report for CCT5
  findings:
  - statement: >-
      The Falcon report was reviewed and synthesized into the CCT5 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: >-
      CCT5 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/CCT5/CCT5-deep-research-falcon.md
      supporting_text: CCT5 is best defined as a **structural and catalytic component**
- term:
    id: GO:0005832
    label: chaperonin-containing T-complex
  qualifier: part_of
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  review:
    summary: CCT5 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 CCT5; 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: >-
      CCT5 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: CCT5 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: CCT5 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: >-
      CCT5 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: >-
      CCT5 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: CCT5 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:19536198
  supporting_entities:
  - UniProtKB:P32324
  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:P32324
  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: >-
      CCT5 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: IPI
  original_reference_id: PMID:15704212
  supporting_entities:
  - SGD:S000002596
  review:
    summary: CCT5 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:0005832
    label: chaperonin-containing T-complex
  qualifier: part_of
  evidence_type: IDA
  original_reference_id: PMID:16762366
  review:
    summary: CCT5 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: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
- 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: >-
    CCT5 is the epsilon 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: >-
    How does the high-ATP-affinity Cct5 subunit shape client progression through the yeast TRiC/CCT ATPase
    cycle?
suggested_experiments:
- hypothesis: >-
    Cct5 ATP binding/hydrolysis helps set the timing of TRiC/CCT chamber closure for actin and tubulin
    clients.
  description: >-
    Compare ATPase-cycle reporters, client folding assays, and viability for targeted CCT5 ATP-pocket
    alleles in yeast, separating assembled-complex abundance from kinetic effects.
  experiment_type: site-directed mutagenesis with chaperonin folding and ATPase assays