TCP1

UniProt ID: P12612
Organism: Saccharomyces cerevisiae
Review Status: COMPLETE
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Gene Description

TCP1 (also known as CCT1) encodes the alpha subunit of the chaperonin-containing T-complex (TRiC/CCT) in S. cerevisiae. TRiC/CCT is an essential, hetero-oligomeric, group II chaperonin composed of eight paralogous subunits (CCT1-8) arranged in two stacked rings of eight subunits each, forming a ~1 MDa complex. The complex functions as an ATP-dependent protein folding machine that assists the folding of actin, tubulin, and a small number of other substrates including WD40-repeat proteins. Each subunit contributes to the overall ATP-dependent protein folding chaperone activity of the complex; individual subunits do not independently fold substrates. TCP1/CCT1 is essential for viability and plays roles in mitotic spindle formation in yeast. The crystal structure of yeast CCT (PMID:21701561) reveals intrinsic asymmetry among the eight subunits, with each displaying unique configurations and substrate-binding properties.

Existing Annotations Review

GO Term Evidence Action Reason
GO:0006457 protein folding
IBA
GO_REF:0000033
ACCEPT
Summary: TCP1 is part of the TRiC/CCT complex that assists protein folding. IBA annotation is consistent with IDA evidence from PMID:16762366 demonstrating that purified yeast CCT catalyses actin folding in vitro.
Reason: Core biological process. The TRiC/CCT complex is an essential protein folding machine, and TCP1 is a required subunit. IBA is well supported by experimental data.
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
file:yeast/TCP1/TCP1-deep-research-falcon.md
TCP1/CCT1 encodes CCT1 (TCP-1; CCT-alpha), one of eight paralogous subunits that assemble into the eukaryotic cytosolic chaperonin TRiC/CCT.
GO:0005832 chaperonin-containing T-complex
IBA
GO_REF:0000033
ACCEPT
Summary: TCP1 is the alpha subunit of the chaperonin-containing T-complex (TRiC/CCT). IBA is consistent with IDA and IPI evidence from PMID:16762366 and PMID:15704212.
Reason: Core complex membership. TCP1 is an integral, essential subunit of TRiC/CCT. Well supported by multiple experimental methods.
GO:0051082 unfolded protein binding
IBA
GO_REF:0000033
MODIFY
Summary: GO:0051082 (unfolded protein binding) is proposed for obsoletion. TCP1, as a subunit of TRiC/CCT, does interact with unfolded substrates (actin, tubulin), but this occurs in the context of the ATP-dependent chaperonin folding cycle, not as a standalone binding function. The correct replacement is GO:0140662 (ATP-dependent protein folding chaperone), with the qualifier contributes_to since TCP1 is a subunit of the complex.
Reason: GO:0051082 is targeted for obsoletion. TCP1 binds unfolded proteins only as part of the TRiC/CCT complex's ATP-dependent folding cycle. The appropriate replacement is GO:0140662 (ATP-dependent protein folding chaperone). This IEA-level annotation via InterPro already exists for this gene.
GO:0000166 nucleotide binding
IEA
GO_REF:0000043
ACCEPT
Summary: TCP1 binds ATP as part of its chaperonin function. This is a parent term of ATP binding and is correct but general.
Reason: Correct. All TRiC/CCT subunits bind nucleotides (ATP/ADP). The more specific term ATP binding (GO:0005524) is also annotated. This broader IEA is acceptable.
GO:0005524 ATP binding
IEA
GO_REF:0000120
ACCEPT
Summary: TCP1 binds ATP through its equatorial domain. Each CCT subunit has an ATP-binding site that is essential for the allosteric chaperonin cycle.
Reason: Correct and fundamental. ATP binding is essential for the TRiC/CCT folding mechanism. UniProt keywords confirm ATP-binding.
GO:0005737 cytoplasm
IEA
GO_REF:0000044
ACCEPT
Summary: TCP1 is a cytoplasmic protein. UniProt subcellular location annotation confirms cytoplasmic localization.
Reason: Correct. TRiC/CCT is a cytoplasmic/cytosolic complex.
GO:0005832 chaperonin-containing T-complex
IEA
GO_REF:0000117
ACCEPT
Summary: Redundant with the IBA and IDA annotations for TRiC/CCT membership. Correct ARBA-based annotation.
Reason: Correct. Redundant with experimental evidence but acceptable.
GO:0006457 protein folding
IEA
GO_REF:0000120
ACCEPT
Summary: Redundant with IBA and IDA annotations for protein folding. Correct.
Reason: Correct. Consistent with IBA and IDA evidence.
GO:0016887 ATP hydrolysis activity
IEA
GO_REF:0000002
ACCEPT
Summary: Each TRiC/CCT subunit has ATPase activity. The crystal structure (PMID:21701561) reveals ATP-binding heterogeneity among subunits, and the complex uses a sequential ATP hydrolysis mechanism.
Reason: Correct. Each CCT subunit contributes ATPase activity to the chaperonin cycle. InterPro-based annotation is well supported.
GO:0051082 unfolded protein binding
IEA
GO_REF:0000120
MODIFY
Summary: GO:0051082 is proposed for obsoletion. Same rationale as the IBA annotation above.
Reason: GO:0051082 is targeted for obsoletion. Should be replaced with GO:0140662 (ATP-dependent protein folding chaperone), which is already annotated via InterPro.
GO:0140662 ATP-dependent protein folding chaperone
IEA
GO_REF:0000002
ACCEPT
Summary: This is the correct molecular function term for TRiC/CCT subunits. InterPro-based annotation via IPR017998 (Chaperone TCP-1). TCP1 contributes to this activity as part of the hetero-oligomeric complex.
Reason: Correct and the most appropriate MF term. GO:0140662 is the proper replacement for the obsoleting GO:0051082. As a complex subunit, the qualifier should ideally be contributes_to rather than enables, but the IEA annotation is correct in substance.
GO:0005515 protein binding
IPI
PMID:16554755
Global landscape of protein complexes in the yeast Saccharom...
MARK AS OVER ANNOTATED
Summary: IPI evidence from the global landscape of protein complexes study (Krogan et al. 2006). TCP1 interacts with POP2 (P39008) and YPP1 (P46951) in TAP-MS experiments.
Reason: Protein binding is uninformative for a chaperonin subunit. Interactions detected in large-scale complex purification studies likely reflect chaperone-substrate or complex-subunit interactions already captured by the TRiC/CCT complex membership annotation. These are better described by the chaperonin complex annotation.
GO:0005515 protein binding
IPI
PMID:19536198
An atlas of chaperone-protein interactions in Saccharomyces ...
MARK AS OVER ANNOTATED
Summary: IPI evidence from the chaperone-protein interactions atlas (Gong et al. 2009). TCP1 interacts with SIT4 (P20604), POP2 (P39008), and YPP1 (P46951).
Reason: Protein binding is uninformative for a chaperonin subunit. These interactions represent chaperonin-substrate relationships that are an inherent part of TRiC/CCT function.
GO:0005515 protein binding
IPI
PMID:20489023
A global protein kinase and phosphatase interaction network ...
MARK AS OVER ANNOTATED
Summary: IPI evidence from a global protein kinase and phosphatase interaction network. TCP1 interacts with SIT4 (P20604).
Reason: Protein binding is uninformative for a chaperonin subunit.
GO:0005515 protein binding
IPI
PMID:21701561
The crystal structure of yeast CCT reveals intrinsic asymmet...
MARK AS OVER ANNOTATED
Summary: IPI evidence from the crystal structure study of yeast CCT. TCP1 interacts with ACT1 (P60010) in the CCT-actin co-crystal structure. This is a well-characterized chaperonin-substrate interaction.
Reason: Protein binding is uninformative. The TCP1-actin interaction is a direct chaperonin-substrate relationship, which is the core function of TRiC/CCT already captured by the protein folding and complex membership annotations.
Supporting Evidence:
PMID:21701561
We have solved the crystal structure of yeast CCT in complex with actin at 3.8 Å resolution, revealing the subunit organisation and the location of discrete patches of co-evolving 'signature residues' that mediate specific interactions between CCT and its substrates.
GO:0005515 protein binding
IPI
PMID:27107014
An inter-species protein-protein interaction network across ...
MARK AS OVER ANNOTATED
Summary: IPI evidence from an inter-species protein-protein interaction network. TCP1 interacts with several human proteins (cross-species interactions).
Reason: Protein binding is uninformative. Cross-species interactions in this context likely reflect conserved chaperonin-substrate relationships.
GO:0005515 protein binding
IPI
PMID:37968396
The social and structural architecture of the yeast protein ...
MARK AS OVER ANNOTATED
Summary: IPI evidence from the social and structural architecture of the yeast protein interactome. TCP1 interacts with SIT4 (P20604).
Reason: Protein binding is uninformative for a chaperonin subunit.
GO:0005515 protein binding
IPI
PMID:9878052
Compartmentation of protein folding in vivo: sequestration o...
MARK AS OVER ANNOTATED
Summary: IPI evidence from the chaperonin-GimC system study (Siegers et al. 1999). TCP1 interacts with ACT1 (P60010). This study demonstrated that TRiC and GimC form an integrated folding compartment that sequesters newly synthesized actin.
Reason: Protein binding is uninformative. The TCP1-actin interaction is a core chaperonin-substrate relationship already captured by the protein folding and complex annotations. The study supports the chaperonin function annotation.
Supporting Evidence:
PMID:9878052
We propose that TRiC and GimC form an integrated 'folding compartment' which functions in cooperation with the translation machinery.
GO:0006457 protein folding
IDA
PMID:16762366
Quantitative actin folding reactions using yeast CCT purifie...
ACCEPT
Summary: PMID:16762366 demonstrated quantitative actin folding using purified yeast CCT. The purified complex catalyses folding of both yeast ACT1p and human beta-actin with nearly identical rate constants.
Reason: Core biological process. Direct experimental demonstration of TRiC/CCT-mediated protein folding in vitro using the purified complex containing TCP1.
Supporting Evidence:
PMID:16762366
Yeast CCT catalyses the folding of yeast ACT1p and human beta-actin with nearly identical rate constants and yields.
GO:0005886 plasma membrane
HDA
PMID:16622836
The plasma membrane proteome of Saccharomyces cerevisiae and...
KEEP AS NON CORE
Summary: HDA evidence from the plasma membrane proteome study. TCP1 was detected in the plasma membrane fraction, though this may reflect co-purification rather than true membrane localization.
Reason: TCP1 was detected in the plasma membrane proteome, but TRiC/CCT is primarily a cytosolic complex. The plasma membrane association may be a minor or artifact localization. Not a core localization.
GO:0005832 chaperonin-containing T-complex
IPI
PMID:15704212
Physiological effects of unassembled chaperonin Cct subunits...
ACCEPT
Summary: PMID:15704212 studied physiological effects of unassembled Cct subunits. TCP1 was shown to be part of the complex through interaction with other subunits (with CCT6/S000002596 as supporting entity).
Reason: Core complex membership with experimental IPI 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:0005832 chaperonin-containing T-complex
IDA
PMID:16762366
Quantitative actin folding reactions using yeast CCT purifie...
ACCEPT
Summary: PMID:16762366 purified the intact yeast CCT complex, confirming TCP1 as a constituent subunit.
Reason: Core complex membership with direct experimental evidence from purified complex.
GO:0051082 unfolded protein binding
IDA
PMID:16762366
Quantitative actin folding reactions using yeast CCT purifie...
MODIFY
Summary: GO:0051082 is proposed for obsoletion. PMID:16762366 demonstrated that the purified CCT complex binds actin folding intermediates (Ac(I)) and processes them to native actin in an ATP-dependent manner. This is chaperonin-mediated folding, not passive unfolded protein binding.
Reason: GO:0051082 is targeted for obsoletion. The experimental evidence from PMID:16762366 actually demonstrates ATP-dependent protein folding chaperone activity. The CCT complex binds actin intermediates in a pre-equilibrium step followed by ATP-driven processing to native actin. This is GO:0140662 (ATP-dependent protein folding chaperone).
Supporting Evidence:
PMID:16762366
The results from this controlled CCT-actin folding assay are consistent with a model where CCT and Ac(I) are in a binding pre-equilibrium with a rate-limiting binding step, followed by a faster ATP-driven processing to native actin.

Core Functions

TCP1 is the alpha subunit of the TRiC/CCT chaperonin complex. It contributes to the complex-level ATP-dependent protein folding chaperone activity (GO:0140662) that folds actin, tubulin, and other substrates. Individual subunits do not independently fold substrates; the activity emerges from the assembled hetero-oligomeric complex. The crystal structure (PMID:21701561) reveals that each subunit has unique configurations and substrate-binding properties, suggesting specialized roles within the complex. TCP1 binds ATP and contributes ATPase activity to the sequential ATP hydrolysis mechanism that drives the chaperonin cycle.

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:21701561
    The cytosolic chaperonin CCT is a 1-MDa protein-folding machine essential for eukaryotic life.
  • file:yeast/TCP1/TCP1-deep-research-falcon.md
    TCP1/CCT1 encodes CCT1 (TCP-1; CCT-alpha), one of eight paralogous subunits that assemble into the eukaryotic cytosolic chaperonin TRiC/CCT. TRiC/CCT is a ~1 MDa ATP-dependent double-ring machine, with eight distinct subunits per ring.
  • file:interpro/panther/PTHR11353/PTHR11353-metadata.yaml
    PANTHER family PTHR11353 is named CHAPERONIN and supports TCP1/CCT1 membership in the conserved chaperonin family.

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.
  • Studied physiological effects of overexpressing individual CCT subunits
    "Overexpression of a single CCT gene in Saccharomyces cerevisiae causes an increase of the corresponding Cct subunit, but not of the Cct complex."
  • Showed that CCT subunits form a stoichiometric array of eight different subunits in two rings
    "Eukaryotic chaperonins, the Cct complexes, are assembled into two rings, each of which is composed of a stoichiometric array of eight different subunits"
Global landscape of protein complexes in the yeast Saccharomyces cerevisiae.
The plasma membrane proteome of Saccharomyces cerevisiae and its response to the antifungal calcofluor.
Quantitative actin folding reactions using yeast CCT purified via an internal tag in the CCT3/gamma subunit.
  • Developed efficient purification protocol for yeast CCT
    "An efficient purification protocol for CCT from Saccharomyces cerevisiae has been developed."
  • Demonstrated quantitative actin folding by purified yeast CCT in vitro
    "Yeast CCT catalyses the folding of yeast ACT1p and human beta-actin with nearly identical rate constants and yields."
  • CCT catalyses folding via a binding pre-equilibrium followed by ATP-driven processing
    "The results from this controlled CCT-actin folding assay are consistent with a model where CCT and Ac(I) are in a binding pre-equilibrium with a rate-limiting binding step, followed by a faster ATP-driven processing to native actin."
An atlas of chaperone-protein interactions in Saccharomyces cerevisiae: implications to protein folding pathways in the cell.
A global protein kinase and phosphatase interaction network in yeast.
The crystal structure of yeast CCT reveals intrinsic asymmetry of eukaryotic cytosolic chaperonins.
  • Solved crystal structure of yeast CCT in complex with actin at 3.8 Å
    "We have solved the crystal structure of yeast CCT in complex with actin at 3.8 Å resolution, revealing the subunit organisation and the location of discrete patches of co-evolving 'signature residues' that mediate specific interactions between CCT and its substrates."
  • Revealed intrinsic asymmetry and subunit individuality in the complex
    "The intrinsic asymmetry is revealed by the structural individuality of the CCT subunits, which display unique configurations, substrate binding properties, ATP-binding heterogeneity and subunit-subunit interactions."
  • CCT uses a sequential rather than concerted ATP hydrolysis mechanism
    "the mechanism by which CCT assists folding is distinct from other chaperonins, with no hydrophobic wall lining a potential Anfinsen cage, and a sequential rather than concerted ATP hydrolysis mechanism."
An inter-species protein-protein interaction network across vast evolutionary distance.
The social and structural architecture of the yeast protein interactome.
Compartmentation of protein folding in vivo: sequestration of non-native polypeptide by the chaperonin-GimC system.
  • TRiC and GimC form an integrated folding compartment for newly synthesized actin
    "We propose that TRiC and GimC form an integrated 'folding compartment' which functions in cooperation with the translation machinery."
  • GimC accelerates actin folding on TRiC at least 5-fold
    "GimC accelerates actin folding at least 5-fold and prevents the premature release of non-native protein from TRiC."
UniProt:P12612
UniProtKB entry for Saccharomyces cerevisiae TCP1/CCT1
  • TCP1 encodes CCT-alpha, a member of the TCP-1 chaperonin family.
    "RecName: Full=T-complex protein 1 subunit alpha; Short=TCP-1-alpha; AltName: Full=CCT-alpha;"
file:yeast/TCP1/TCP1-deep-research-falcon.md
Falcon deep research report for yeast TCP1/CCT1
  • TCP1/CCT1 is a TRiC/CCT subunit in the cytosolic ATP-dependent chaperonin complex.
    "TCP1/CCT1 encodes CCT1 (TCP-1; CCT-alpha), one of eight paralogous subunits that assemble into the eukaryotic cytosolic chaperonin TRiC/CCT."
file:interpro/panther/PTHR11353/PTHR11353-metadata.yaml
PANTHER family PTHR11353 chaperonin metadata
  • PTHR11353 supports TCP1 as part of the conserved chaperonin family.
    "PANTHER family PTHR11353 is named CHAPERONIN and integrates InterPro IPR017998."

Suggested Questions for Experts

Q: Which yeast TRiC/CCT substrates require CCT1-specific apical or chamber-facing contacts rather than generic complex-level chaperonin activity?

Q: Should the emerging nuclear TRiC/CCT RNA polymerase II role be curated for TCP1 after peer-reviewed confirmation, or treated as a non-core complex phenotype?

Suggested Experiments

Experiment: Combine CCT1 apical/chamber-surface mutants with purified yeast TRiC folding assays and in vivo client abundance/activity readouts for ACT1, tubulins, Cdh1, and Cdc20.

Hypothesis: CCT1 contributes substrate-specific contacts that are required for efficient folding of selected actin, tubulin, or WD40-repeat clients.

Type: client-specific folding assay

Experiment: Validate nuclear TRiC occupancy and RNAPII/RNA phenotypes using independently tagged CCT subunits, acute degron or anchor-away perturbations, and rescue with cytoplasm-restricted versus nucleus-permissive CCT1 variants.

Hypothesis: The nuclear RNA polymerase II phenotype of cct1-2 reflects assembled TRiC/CCT function rather than indirect cytoplasmic proteostasis stress.

Type: nuclear TRiC validation

📚 Additional Documentation

Deep Research Falcon

(TCP1-deep-research-falcon.md)

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template_file: templates/gene_research_go_focused.md
template_variables:
organism: yeast
gene_id: TCP1
gene_symbol: TCP1
uniprot_accession: P12612
protein_description: 'RecName: Full=T-complex protein 1 subunit alpha; Short=TCP-1-alpha;
AltName: Full=CCT-alpha;'
gene_info: Name=TCP1; Synonyms=CCT1; OrderedLocusNames=YDR212W; ORFNames=YD8142.13,
YD8142B.04;
organism_full: Saccharomyces cerevisiae (strain ATCC 204508 / S288c) (Baker's yeast).
protein_family: Belongs to the TCP-1 chaperonin family. .
protein_domains: Chap_CCT_alpha. (IPR012715); Chaperone_TCP-1. (IPR017998); Chaperonin_TCP-1_CS.
(IPR002194); Cpn60/GroEL/TCP-1. (IPR002423); GroEL-like_apical_dom_sf. (IPR027409)
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citation_count: 31


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: P12612
  • Protein Description: RecName: Full=T-complex protein 1 subunit alpha; Short=TCP-1-alpha; AltName: Full=CCT-alpha;
  • Gene Information: Name=TCP1; Synonyms=CCT1; OrderedLocusNames=YDR212W; ORFNames=YD8142.13, YD8142B.04;
  • Organism (full): Saccharomyces cerevisiae (strain ATCC 204508 / S288c) (Baker's yeast).
  • Protein Family: Belongs to the TCP-1 chaperonin family. .
  • Key Domains: Chap_CCT_alpha. (IPR012715); 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 "TCP1" 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 'TCP1' 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 TCP1 (gene ID: TCP1, UniProt: P12612) 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: P12612
  • Protein Description: RecName: Full=T-complex protein 1 subunit alpha; Short=TCP-1-alpha; AltName: Full=CCT-alpha;
  • Gene Information: Name=TCP1; Synonyms=CCT1; OrderedLocusNames=YDR212W; ORFNames=YD8142.13, YD8142B.04;
  • Organism (full): Saccharomyces cerevisiae (strain ATCC 204508 / S288c) (Baker's yeast).
  • Protein Family: Belongs to the TCP-1 chaperonin family. .
  • Key Domains: Chap_CCT_alpha. (IPR012715); 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 "TCP1" 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 'TCP1' 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 TCP1 (gene ID: TCP1, UniProt: P12612) 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: Saccharomyces cerevisiae TCP1/CCT1 (UniProt P12612) — functional annotation

0) Target verification (critical disambiguation)

The UniProt entry provided (P12612) describes T-complex protein 1 subunit alpha (also called TCP-1-alpha, CCT-alpha) encoded by TCP1 (synonym CCT1) in Saccharomyces cerevisiae S288c. The literature gathered here consistently uses TCP1/CCT1 to refer to the CCT/TRiC cytosolic group II chaperonin subunit (not unrelated “TCP1” symbols in other organisms), including yeast genetics that explicitly uses a cct1-2 temperature-sensitive allele to perturb TRiC/CCT function. (gvozdenov2024triccctchaperoningoverns pages 30-33, narayanan2021sorbitolandpkc1 pages 1-3)

Limitation: within the retrieved full-text corpus, I did not find an explicit string mapping (e.g., “UniProt P12612” or “YDR212W”) inside the papers; thus, the identifier-level mapping to P12612/YDR212W is taken from the user-provided UniProt record, while mechanistic/functional claims are supported by peer-reviewed literature on yeast CCT1/TCP1. (gvozdenov2024triccctchaperoningoverns pages 30-33, narayanan2021sorbitolandpkc1 pages 1-3)

1) Key concepts and current understanding (definitions and mechanism)

1.1 What TCP1/CCT1 is

TCP1/CCT1 encodes CCT1 (TCP-1; CCT-alpha), one of eight paralogous subunits that assemble into the eukaryotic cytosolic chaperonin TRiC/CCT. TRiC/CCT is a ~1 MDa ATP-dependent double-ring machine, with eight distinct subunits per ring (CCT1–CCT8), and each subunit has apical/intermediate/equatorial domains; the equatorial domain binds ATP and supports ring assembly, while apical surfaces mediate substrate recognition and the built-in lid. (gestaut2019theatppoweredgymnastics pages 1-2, que2024theroleof pages 2-4, willison2018thesubstratespecificity pages 1-2)

1.2 What TRiC/CCT does (primary molecular function)

TRiC/CCT’s primary biological function is ATP-coupled folding (and in some cases assembly/biogenesis) of a select set of cytosolic proteins, especially those that are topologically complex and aggregation-prone. Substrates bind TRiC in non-native conformations; ATP binding/hydrolysis drives conformational changes that close the chamber and promote productive folding. (gestaut2019theatppoweredgymnastics pages 1-2, gestaut2019theatppoweredgymnastics pages 4-5)

Quantitatively, TRiC/CCT is commonly estimated to engage on the order of ~10% of cytosolic proteins (review-level estimate), reflecting a substantial but selective role in proteostasis. (que2024theroleof pages 2-4, gestaut2019theatppoweredgymnastics pages 4-5)

1.3 Subunit specialization and what “CCT1-specific” means

TRiC/CCT subunits are not redundant: subunit diversification creates asymmetry in ATP binding/allostery and in substrate-recognition surfaces. A key mechanistic concept is a hierarchy of ATP affinities across subunits; in one model, the “high-affinity hemisphere” includes CCT5, CCT4, CCT1, and CCT2, which initiates ATP-driven conformational transitions. (gestaut2019theatppoweredgymnastics pages 4-5)

2) Molecular function and substrate/client specificity (yeast-focused)

2.1 Core/obligate clients

In budding yeast and across eukaryotes, the most established obligate clients of TRiC/CCT are actin and tubulin, which require TRiC/CCT to reach native, functional states. (willison2018thesubstratespecificity pages 1-2, gestaut2019theatppoweredgymnastics pages 4-5)

2.2 WD40/β-propeller proteins and cell-cycle regulation

A major additional client class is WD40-repeat β-propeller proteins. In yeast, TRiC/CCT is reported as the only known folding pathway producing functional, active Cdh1p and Cdc20p (APC/C coactivators that are WD40 propellers), linking TRiC directly to cell-cycle control via APC/C regulation. (willison2018thesubstratespecificity pages 6-6, willison2018thesubstratespecificity pages 1-2)

In a targeted analysis of yeast 7-bladed WD40 proteins (plus one 8-bladed WD40 protein), many showed some binding to CCT, but only a subset were strong interactors (including Cdh1p and Cdc20p), consistent with a restricted substrate spectrum rather than generic folding of all WD40 proteins. (willison2018thesubstratespecificity pages 5-6)

2.3 Substrate-binding logic

Substrate specificity is driven largely by apical domain surfaces that differ among subunits, enabling polyvalent, subunit-selective binding. Review synthesis emphasizes that TRiC tends to fold proteins enriched in β-structure/topological complexity and that it can act as a folding machine and/or a regulated holding/assembly platform for some propellers. (gestaut2019theatppoweredgymnastics pages 4-5, willison2018thesubstratespecificity pages 5-6, monkemeyer2019structuralandfunctional pages 29-31)

3) Cellular localization and where TCP1/CCT1 acts

3.1 Canonical localization: cytosol

TRiC/CCT is classically a cytosolic chaperonin, functioning co- and post-translationally in general proteostasis and in cytoskeletal protein biogenesis (actin/tubulin). (que2024theroleof pages 2-4, willison2018thesubstratespecificity pages 1-2)

3.2 Emerging localization/function: nucleus (2024 preprint)

Recent work in budding yeast reports an assembled TRiC/CCT pool in the nucleus (supported by GFP-tagged subunits and biochemical fractionation/SEC consistent with a ~1 MDa holo-complex in nuclear fractions), and uses the cct1-2 allele to show nuclear TRiC/CCT modulates RNA polymerase II activity and RNA homeostasis. (gvozdenov2024triccctchaperoningoverns pages 6-9, gvozdenov2024triccctchaperoningoverns pages 13-17)

4) Pathways and biological processes involving TCP1/CCT1

4.1 Proteostasis networks and translation-coupled folding

CCT/TRiC is discussed as a major ribosome-associated chaperone within the CLIPS (Chaperones Linked to Protein Synthesis) network, connecting TCP1/CCT1 function to translation elongation and nascent-chain maturation. (que2024theroleof pages 2-4)

4.2 Cell cycle control via folding of APC/C coactivators

By folding the WD40 propeller proteins Cdh1p and Cdc20p, TRiC/CCT contributes directly to APC/C function and thus cell-cycle progression. (willison2018thesubstratespecificity pages 6-6, willison2018thesubstratespecificity pages 1-2)

4.3 Cell wall integrity and stress signaling (phenotype-based linkage)

A yeast cct1-2 mutant shows sensitivity to cell-wall stress agents (SDS, congo red), and its temperature sensitivity is suppressed by 1 M sorbitol or PKC1 overexpression (PKC1 is a key regulator of the yeast cell wall integrity pathway). This supports a functional link between TRiC/CCT proteostasis and maintenance of cell wall integrity, likely via folding/biogenesis of proteins required for cell wall homeostasis. (narayanan2021sorbitolandpkc1 pages 1-3)

4.4 RNA homeostasis / transcriptional control (2024 preprint)

In the 2024 preprint, TRiC/CCT inactivation using cct1-2 causes widespread transcriptional/RNA anomalies, including extensive accumulation of cryptic/noncoding RNAs and increased intergenic transcription. The authors propose TRiC acts as an RNAPII “rheostat” linking proteostasis state to transcriptional output. (gvozdenov2024triccctchaperoningoverns pages 6-9, gvozdenov2024triccctchaperoningoverns pages 13-17)

5) Recent developments (prioritizing 2023–2024)

5.1 ATP-driven folding cycle and cochaperone coordination (2024)

High-resolution cryo-EM and crosslinking mass spectrometry has advanced mechanistic understanding of how TRiC cooperates with cochaperones (e.g., prefoldin and phosducin-like proteins). In particular, 2024 structural work shows an ATP-driven cycle in which PhLP2A binds open TRiC via subunit-selective contacts and rearranges upon chamber closure; in substrate-containing complexes, inner-surface contacts involve a subset of subunits including CCT1. (junsun2024astructuralvista pages 1-2)

5.2 Subunit-specific contacts involving CCT1 (2024)

The 2024 Nature Communications study reports that actin and/or PhLP2A engage positively charged chamber-facing residues from CCT1/CCT3/CCT6/CCT8, and crosslinks can place cochaperone helices proximal to CCT1 cavity-facing residues, supporting direct involvement of CCT1 surfaces in substrate/cochaperone positioning inside the folding chamber. (junsun2024astructuralvista pages 1-2)

5.3 Mechanochemistry in yeast: nucleotide exchange kinetics (2023)

A 2023 yeast kinetic analysis of a disease-linked CCT2 double mutation shows that slowing ADP off-rate can stabilize the closed state and that TRiC ATPase activity is stimulated by a non-folded substrate. Although this work is on CCT2, it strengthens the mechanistic framework for how the TRiC ATPase cycle (in which CCT1 is part of the high-affinity hemisphere) couples nucleotide exchange to folding output. (roy2023reducedadpoffrate pages 1-2, gestaut2019theatppoweredgymnastics pages 4-5)

5.4 Substrate folding intermediates visualized by cryo-EM (2023)

A 2023 cryo-EM ensemble of substrate-engaged TRiC states (human endogenous TRiC with tubulin) provides a modern reference trajectory for how substrates move and stabilize during ring closure across the ATPase cycle. While not yeast-specific, the mechanism supports functional inference for yeast TCP1/CCT1 as part of the conserved folding machine for tubulin-class substrates. (liu2023pathwayandmechanism pages 1-2)

6) Quantitative data and statistics (from recent and authoritative sources)

6.1 Client fraction / proteome coverage

CCT/TRiC is commonly estimated to assist folding/maturation of ~10% of cytoplasmic proteins (review synthesis). (que2024theroleof pages 2-4, gestaut2019theatppoweredgymnastics pages 4-5)

6.2 Yeast expression proxies (mRNA copy number estimates)

A quantitative figure caption in an authoritative substrate-specificity review reports yeast mRNA copy-number estimates: TCP1 ~1.81 mRNA copies/cell, with similar magnitudes for other CCT subunits, and much higher values for abundant clients such as ACT1 ~28.97 and TUB2 ~5.94. (willison2018thesubstratespecificity media 549e9c0a, willison2018thesubstratespecificity media 4a831a29)

6.3 Yeast nuclear transcription phenotypes (2024 preprint)

In the cct1-2 mutant background, the preprint reports strong genome-wide RNA effects. Examples include: intergenic coverage increasing dramatically, and a substantial fraction of the genome exhibiting strong nascent-RNA increases (e.g., ~22.8% of the genome meeting a ≥4-fold threshold for increased nascent RNAs in one analysis), plus measurable readthrough/termination defects at subsets of snoRNA loci. (gvozdenov2024triccctchaperoningoverns pages 6-9, gvozdenov2024triccctchaperoningoverns pages 13-17)

7) Current applications and real-world implementations

7.1 Yeast as an experimental platform for chaperonin biology (and disease-linked mechanisms)

Temperature-sensitive yeast TRiC mutants (including cct1-2) are used as tractable tools for genetic suppression screens and pathway probing, as demonstrated by suppression of cct phenotypes via osmotic stabilization or PKC1 overexpression. This is a concrete real-world implementation of TCP1/CCT1 genetics for dissecting cellular proteostasis and stress pathways. (narayanan2021sorbitolandpkc1 pages 1-3)

7.2 Informing intervention strategies by resolving substrate-specific interactions

Modern structural studies of TRiC with clients/cochaperones are explicitly discussed as informing design of agents targeting TRiC–substrate interactions (e.g., in tubulin folding contexts). While this is largely developed in mammalian systems, it represents translationally oriented use of TRiC mechanistic knowledge enabled by conserved chaperonin architecture that includes CCT1/CCT-alpha. (liu2023pathwayandmechanism pages 1-2)

8) Expert synthesis and interpretation (authoritative perspectives)

A consistent expert view is that TRiC/CCT is a specialist folding machine (not a generalist chaperone), focusing on a restricted client set enriched for difficult-to-fold, aggregation-prone, β-structure-rich proteins, and that subunit diversification (including CCT1) is central to this specialization via asymmetric ATP allostery and subunit-specific binding surfaces. (gestaut2019theatppoweredgymnastics pages 4-5, willison2018thesubstratespecificity pages 7-8, monkemeyer2019structuralandfunctional pages 29-31)

9) Summary evidence map (key sources)

The following table lists the most relevant recent and foundational sources used for this annotation, emphasizing 2023–2024 where available.

Year Citation (short) Publication type Key contribution for TCP1/CCT1 functional annotation Organism/system URL/DOI
2024 Gvozdenov et al. 2024 Preprint Uses the yeast cct1-2 allele to show TRiC/CCT has an assembled nuclear pool and directly modulates RNA polymerase II activity and RNA homeostasis; expands TCP1/CCT1 annotation beyond canonical cytosolic folding to nuclear transcriptional control in budding yeast (gvozdenov2024triccctchaperoningoverns pages 6-9, gvozdenov2024triccctchaperoningoverns pages 13-17, gvozdenov2024triccctchaperoningoverns pages 30-33) Saccharomyces cerevisiae https://doi.org/10.1101/2024.09.26.615188
2024 Park et al. 2024 Primary research Cryo-EM/XL-MS defines ATP-driven cooperation between PhLP2A and TRiC; identifies chamber-facing contacts involving CCT1/CCT3/CCT6/CCT8, supporting a subunit-specific inner-surface role for CCT1/TCP1 in substrate/cochaperone positioning during folding (junsun2024astructuralvista pages 1-2) Mammalian TRiC with general eukaryotic relevance https://doi.org/10.1038/s41467-024-45242-x
2024 Que et al. 2024 Review Summarizes CCT/TRiC as a 1-MDa ATP-dependent 16-subunit complex and major ribosome-associated chaperone in the CLIPS network, assisting folding of roughly 10% of cytoplasmic proteins; useful for defining TCP1/CCT1 core function in translation-linked proteostasis (que2024theroleof pages 2-4) General eukaryotes, includes yeast context https://doi.org/10.1016/j.heliyon.2024.e29029
2023 Roy et al. 2023 Primary research Yeast kinetic study of disease-linked CCT2 mutation shows altered ADP off-rate and stabilization of the closed state, clarifying TRiC mechanochemistry relevant to interpreting how ATP-driven cycling supports functions of all subunits including TCP1/CCT1 (roy2023reducedadpoffrate pages 1-2) Saccharomyces cerevisiae https://doi.org/10.1038/s42003-023-05261-8
2023 Liu et al. 2023 Primary research Cryo-EM captures the tubulin folding pathway through the TRiC ATPase cycle, showing staged substrate translocation and stabilization in the chamber; provides current mechanistic framework for annotating TCP1/CCT1 as part of the ATP-driven folding machine (liu2023pathwayandmechanism pages 1-2) Human endogenous TRiC; mechanism relevant to eukaryotes including yeast https://doi.org/10.1038/s42003-023-04915-x
2019 Gestaut et al. 2019 Review Authoritative review of asymmetric ATP-driven allostery in TRiC/CCT; places CCT1 in the higher-ATP-affinity hemisphere with CCT5/4/2 and explains how subunit diversification underlies specialized substrate contacts and folding dynamics (gestaut2019theatppoweredgymnastics pages 4-5) General eukaryotes with yeast emphasis https://doi.org/10.1016/j.sbi.2019.03.002
2018 Willison 2018 Review Landmark substrate-specificity review: defines CCT/TRiC clients as actin, tubulin, and selected WD40 proteins; notes that yeast TCP1 is a core subunit and gives useful yeast quantitative context, including TCP1 mRNA copy number ~1.81/cell and strong links to Cdh1/Cdc20 folding (willison2018thesubstratespecificity pages 6-6, willison2018thesubstratespecificity pages 7-8, willison2018thesubstratespecificity pages 1-2, willison2018thesubstratespecificity pages 5-6, willison2018thesubstratespecificity media 549e9c0a) Saccharomyces cerevisiae and comparative eukaryotes https://doi.org/10.1098/rstb.2017.0192

Table: This table summarizes the most relevant recent and foundational sources for annotating yeast TCP1/CCT1 as a TRiC/CCT subunit. It highlights what each paper contributes to understanding molecular function, subunit-specific roles, and cellular pathways.

A yeast-focused evidence map of TCP1/CCT1 functional annotation categories is provided here.

Category Key points Best supporting evidence Notes/limitations
molecular function TCP1/CCT1 is the alpha subunit of the essential eukaryotic cytosolic chaperonin TRiC/CCT, a ~1 MDa ATP-dependent double-ring complex with eight distinct subunits per ring. Its primary function is not catalysis of a small-molecule reaction but ATP-coupled assistance of protein folding by binding non-native polypeptides and promoting their productive folding inside the chamber. CCT1 is part of the higher-ATP-affinity hemisphere that helps drive allosteric ring closure and substrate handling. Willison 2018; Gestaut 2019; Que 2024 (willison2018thesubstratespecificity pages 1-2, gestaut2019theatppoweredgymnastics pages 4-5, que2024theroleof pages 2-4) Most mechanistic detail is for the whole TRiC/CCT complex rather than TCP1 alone; direct yeast CCT1 biochemical dissection is limited in the retrieved literature.
clients Best-supported obligate/major client classes are actin and tubulin, plus a restricted subset of WD40/β-propeller proteins including APC/C regulators Cdh1p and Cdc20p. CCT recognizes topologically complex, aggregation-prone substrates and can serve as an assembly/holding platform for some propeller proteins rather than simply releasing a fully folded monomer. Willison 2018; Gestaut 2019; Que 2024 (willison2018thesubstratespecificity pages 1-2, willison2018thesubstratespecificity pages 5-6, willison2018thesubstratespecificity pages 7-8, gestaut2019theatppoweredgymnastics pages 4-5, que2024theroleof pages 2-4) Many client assignments are to the CCT complex as a whole; subunit-specific client preference for yeast CCT1 is inferred from chamber asymmetry and apical-domain specialization.
localization Canonically cytosolic, where it acts co- and post-translationally in proteostasis and cytoskeletal protein biogenesis. Recent yeast work also supports an assembled nuclear TRiC/CCT pool, with cct1-2 perturbation affecting nuclear RNA metabolism and RNA polymerase II output. Gvozdenov 2024; Willison 2018 (gvozdenov2024triccctchaperoningoverns pages 6-9, gvozdenov2024triccctchaperoningoverns pages 13-17, gvozdenov2024triccctchaperoningoverns pages 30-33, willison2018thesubstratespecificity pages 7-8) Nuclear role comes from a 2024 preprint and should be treated as emerging rather than fully settled.
pathways Strongest pathway links are proteostasis, cytoskeleton biogenesis, cell-cycle control, translation-linked folding (CLIPS network), and assembly/function of WD40-containing regulators. Emerging evidence adds transcription/RNA homeostasis via RNAP II regulation in yeast nuclei. Cell-wall integrity phenotypes indicate indirect coupling to PKC1-dependent stress pathways. Willison 2018; Que 2024; Gvozdenov 2024; Narayanan 2021 (willison2018thesubstratespecificity pages 7-8, que2024theroleof pages 2-4, gvozdenov2024triccctchaperoningoverns pages 13-17, narayanan2021sorbitolandpkc1 pages 1-3) Some pathway links are direct client-folding effects; others are downstream consequences of proteostasis failure.
subunit-specific evidence for CCT1 CCT1 contributes specialized chamber/apical surfaces for substrate or cochaperone contacts and participates in the high-affinity ATPase hemisphere. Structural data show actin/PhLP2A interactions involving chamber-facing residues from CCT1 together with CCT3/6/8, supporting a direct role in substrate/cochaperone positioning during the folding cycle. Park 2024; Gestaut 2019 (junsun2024astructuralvista pages 1-2, gestaut2019theatppoweredgymnastics pages 4-5) Structural evidence is from mammalian TRiC, but the subunit architecture and mechanism are highly conserved and routinely used to interpret yeast CCT1/TCP1.
phenotypes Yeast cct1-2 is temperature-sensitive, with growth at 30°C and severe defects at higher temperature; mutants are also sensitive to SDS and congo red, implicating cell-wall integrity defects. Sorbitol and PKC1 overexpression suppress temperature sensitivity, whereas HSP82 overexpression does not. In a newer nuclear context, cct1-2 causes strong accumulation of cryptic/noncoding RNAs and altered transcriptional outputs. Narayanan 2021; Gvozdenov 2024 (narayanan2021sorbitolandpkc1 pages 1-3, gvozdenov2024triccctchaperoningoverns pages 6-9, gvozdenov2024triccctchaperoningoverns pages 13-17, gvozdenov2024triccctchaperoningoverns pages 30-33) Phenotypes reflect loss of complex function, not necessarily a unique moonlighting activity of TCP1 alone.
quantitative data CCT is estimated to assist folding/maturation of about 10% of cytoplasmic proteins. Yeast TCP1 mRNA copy number is reported at ~1.81 per cell, alongside similar low-copy expression of other CCT subunits; ACT1 and TUB2 are much higher (~28.97 and ~5.94). In yeast cct1-2, nascent RNAs increased broadly (~22.8% of genome ≥4-fold), and intergenic transcription rose strongly; ~30 of 68 snoRNAs showed readthrough defects in the 2024 preprint. Que 2024; Willison 2018; Gvozdenov 2024 (que2024theroleof pages 2-4, willison2018thesubstratespecificity pages 7-8, willison2018thesubstratespecificity media 549e9c0a, gvozdenov2024triccctchaperoningoverns pages 6-9, gvozdenov2024triccctchaperoningoverns pages 13-17) Some values are review-derived or preprint-derived; copy-number figures are mRNA estimates, not protein stoichiometry.

Table: This table summarizes the most relevant functional annotation points for yeast TCP1/CCT1, organized by molecular role, clients, localization, pathways, phenotypes, and quantitative evidence. It is designed as a compact evidence map for building the final research report.

10) References (URLs and dates from retrieved corpus)

  • Willison KR. 2018-06. Phil Trans R Soc B “The substrate specificity of eukaryotic cytosolic chaperonin CCT”. https://doi.org/10.1098/rstb.2017.0192 (willison2018thesubstratespecificity pages 6-6, willison2018thesubstratespecificity pages 1-2)
  • Gestaut D, Limatola A, Joachimiak L, Frydman J. 2019-04. Curr Opin Struct Biol “The ATP-powered gymnastics of TRiC/CCT…”. https://doi.org/10.1016/j.sbi.2019.03.002 (gestaut2019theatppoweredgymnastics pages 1-2, gestaut2019theatppoweredgymnastics pages 4-5)
  • Liu C et al. 2023-05. Communications Biology “Pathway and mechanism of tubulin folding…”. https://doi.org/10.1038/s42003-023-04915-x (liu2023pathwayandmechanism pages 1-2)
  • Roy M et al. 2023-08. Communications Biology “Reduced ADP off-rate by the yeast CCT2 double mutation…”. https://doi.org/10.1038/s42003-023-05261-8 (roy2023reducedadpoffrate pages 1-2)
  • Park J et al. 2024-02. Nature Communications “A structural vista of PhLP2A–TRiC cooperation…”. https://doi.org/10.1038/s41467-024-45242-x (junsun2024astructuralvista pages 1-2)
  • Que Y et al. 2024-04. Heliyon “The role of molecular chaperone CCT/TRiC in translation elongation: A literature review”. https://doi.org/10.1016/j.heliyon.2024.e29029 (que2024theroleof pages 2-4)
  • Gvozdenov Z et al. 2024-09. bioRxiv preprint “TRiC/CCT chaperonin governs RNA polymerase II activity in the nucleus…”. https://doi.org/10.1101/2024.09.26.615188 (gvozdenov2024triccctchaperoningoverns pages 6-9, gvozdenov2024triccctchaperoningoverns pages 13-17)
  • Narayanan A, Kabir MA. 2021-08. microPublication Biology “Sorbitol and PKC1 overexpression alleviate temperature sensitivity in chaperonin mutants…”. https://doi.org/10.17912/micropub.biology.000440 (narayanan2021sorbitolandpkc1 pages 1-3)

References

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Citations

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  5. liu2023pathwayandmechanism pages 1-2
  6. roy2023reducedadpoffrate pages 1-2
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  26. https://doi.org/10.1016/j.heliyon.2024.e29029,
  27. https://doi.org/10.1098/rstb.2017.0192,
  28. https://doi.org/10.5282/edoc.23750,
  29. https://doi.org/10.1038/s41467-024-45242-x,
  30. https://doi.org/10.1038/s42003-023-05261-8,
  31. https://doi.org/10.1038/s42003-023-04915-x,

📄 View Raw YAML

id: P12612
gene_symbol: TCP1
product_type: PROTEIN
status: COMPLETE
taxon:
  id: NCBITaxon:559292
  label: Saccharomyces cerevisiae
description: >-
  TCP1 (also known as CCT1) encodes the alpha subunit of the chaperonin-containing T-complex
  (TRiC/CCT) in S. cerevisiae. TRiC/CCT is an essential, hetero-oligomeric, group II chaperonin
  composed of eight paralogous subunits (CCT1-8) arranged in two stacked rings of eight subunits
  each, forming a ~1 MDa complex. The complex functions as an ATP-dependent protein folding
  machine that assists the folding of actin, tubulin, and a small number of other substrates
  including WD40-repeat proteins. Each subunit contributes to the overall ATP-dependent protein
  folding chaperone activity of the complex; individual subunits do not independently fold
  substrates. TCP1/CCT1 is essential for viability and plays roles in mitotic spindle formation
  in yeast. The crystal structure of yeast CCT (PMID:21701561) reveals intrinsic asymmetry
  among the eight subunits, with each displaying unique configurations and substrate-binding
  properties.
existing_annotations:
# ============================================================
# IBA ANNOTATIONS (phylogenetically inferred)
# ============================================================
- term:
    id: GO:0006457
    label: protein folding
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  review:
    summary: >-
      TCP1 is part of the TRiC/CCT complex that assists protein folding. IBA annotation
      is consistent with IDA evidence from PMID:16762366 demonstrating that purified yeast
      CCT catalyses actin folding in vitro.
    action: ACCEPT
    reason: >-
      Core biological process. The TRiC/CCT complex is an essential protein folding machine,
      and TCP1 is a required subunit. IBA is well supported by experimental data.
    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_id: file:yeast/TCP1/TCP1-deep-research-falcon.md
        supporting_text: >-
          TCP1/CCT1 encodes CCT1 (TCP-1; CCT-alpha), one of eight paralogous
          subunits that assemble into the eukaryotic cytosolic chaperonin
          TRiC/CCT.
- term:
    id: GO:0005832
    label: chaperonin-containing T-complex
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  review:
    summary: >-
      TCP1 is the alpha subunit of the chaperonin-containing T-complex (TRiC/CCT). IBA is
      consistent with IDA and IPI evidence from PMID:16762366 and PMID:15704212.
    action: ACCEPT
    reason: >-
      Core complex membership. TCP1 is an integral, essential subunit of TRiC/CCT.
      Well supported by multiple experimental methods.
- term:
    id: GO:0051082
    label: unfolded protein binding
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  review:
    summary: >-
      GO:0051082 (unfolded protein binding) is proposed for obsoletion. TCP1, as a subunit
      of TRiC/CCT, does interact with unfolded substrates (actin, tubulin), but this occurs
      in the context of the ATP-dependent chaperonin folding cycle, not as a standalone
      binding function. The correct replacement is GO:0140662 (ATP-dependent protein folding
      chaperone), with the qualifier contributes_to since TCP1 is a subunit of the complex.
    action: MODIFY
    reason: >-
      GO:0051082 is targeted for obsoletion. TCP1 binds unfolded proteins only as part of
      the TRiC/CCT complex's ATP-dependent folding cycle. The appropriate replacement is
      GO:0140662 (ATP-dependent protein folding chaperone). This IEA-level annotation via
      InterPro already exists for this gene.
    proposed_replacement_terms:
      - id: GO:0140662
        label: ATP-dependent protein folding chaperone
# ============================================================
# IEA ANNOTATIONS (computationally inferred)
# ============================================================
- term:
    id: GO:0000166
    label: nucleotide binding
  evidence_type: IEA
  original_reference_id: GO_REF:0000043
  review:
    summary: >-
      TCP1 binds ATP as part of its chaperonin function. This is a parent term of ATP binding
      and is correct but general.
    action: ACCEPT
    reason: >-
      Correct. All TRiC/CCT subunits bind nucleotides (ATP/ADP). The more specific term
      ATP binding (GO:0005524) is also annotated. This broader IEA is acceptable.
- term:
    id: GO:0005524
    label: ATP binding
  evidence_type: IEA
  original_reference_id: GO_REF:0000120
  review:
    summary: >-
      TCP1 binds ATP through its equatorial domain. Each CCT subunit has an ATP-binding
      site that is essential for the allosteric chaperonin cycle.
    action: ACCEPT
    reason: >-
      Correct and fundamental. ATP binding is essential for the TRiC/CCT folding mechanism.
      UniProt keywords confirm ATP-binding.
- term:
    id: GO:0005737
    label: cytoplasm
  evidence_type: IEA
  original_reference_id: GO_REF:0000044
  review:
    summary: >-
      TCP1 is a cytoplasmic protein. UniProt subcellular location annotation confirms
      cytoplasmic localization.
    action: ACCEPT
    reason: >-
      Correct. TRiC/CCT is a cytoplasmic/cytosolic complex.
- term:
    id: GO:0005832
    label: chaperonin-containing T-complex
  evidence_type: IEA
  original_reference_id: GO_REF:0000117
  review:
    summary: >-
      Redundant with the IBA and IDA annotations for TRiC/CCT membership. Correct ARBA-based
      annotation.
    action: ACCEPT
    reason: >-
      Correct. Redundant with experimental evidence but acceptable.
- term:
    id: GO:0006457
    label: protein folding
  evidence_type: IEA
  original_reference_id: GO_REF:0000120
  review:
    summary: >-
      Redundant with IBA and IDA annotations for protein folding. Correct.
    action: ACCEPT
    reason: >-
      Correct. Consistent with IBA and IDA evidence.
- term:
    id: GO:0016887
    label: ATP hydrolysis activity
  evidence_type: IEA
  original_reference_id: GO_REF:0000002
  review:
    summary: >-
      Each TRiC/CCT subunit has ATPase activity. The crystal structure (PMID:21701561)
      reveals ATP-binding heterogeneity among subunits, and the complex uses a sequential
      ATP hydrolysis mechanism.
    action: ACCEPT
    reason: >-
      Correct. Each CCT subunit contributes ATPase activity to the chaperonin cycle.
      InterPro-based annotation is well supported.
- term:
    id: GO:0051082
    label: unfolded protein binding
  evidence_type: IEA
  original_reference_id: GO_REF:0000120
  review:
    summary: >-
      GO:0051082 is proposed for obsoletion. Same rationale as the IBA annotation above.
    action: MODIFY
    reason: >-
      GO:0051082 is targeted for obsoletion. Should be replaced with GO:0140662
      (ATP-dependent protein folding chaperone), which is already annotated via InterPro.
    proposed_replacement_terms:
      - id: GO:0140662
        label: ATP-dependent protein folding chaperone
- term:
    id: GO:0140662
    label: ATP-dependent protein folding chaperone
  evidence_type: IEA
  original_reference_id: GO_REF:0000002
  review:
    summary: >-
      This is the correct molecular function term for TRiC/CCT subunits. InterPro-based
      annotation via IPR017998 (Chaperone TCP-1). TCP1 contributes to this activity as
      part of the hetero-oligomeric complex.
    action: ACCEPT
    reason: >-
      Correct and the most appropriate MF term. GO:0140662 is the proper replacement for
      the obsoleting GO:0051082. As a complex subunit, the qualifier should ideally be
      contributes_to rather than enables, but the IEA annotation is correct in substance.
# ============================================================
# IPI ANNOTATIONS (protein binding)
# ============================================================
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:16554755
  review:
    summary: >-
      IPI evidence from the global landscape of protein complexes study (Krogan et al. 2006).
      TCP1 interacts with POP2 (P39008) and YPP1 (P46951) in TAP-MS experiments.
    action: MARK_AS_OVER_ANNOTATED
    reason: >-
      Protein binding is uninformative for a chaperonin subunit. Interactions detected in
      large-scale complex purification studies likely reflect chaperone-substrate or
      complex-subunit interactions already captured by the TRiC/CCT complex membership
      annotation. These are better described by the chaperonin complex annotation.
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:19536198
  review:
    summary: >-
      IPI evidence from the chaperone-protein interactions atlas (Gong et al. 2009).
      TCP1 interacts with SIT4 (P20604), POP2 (P39008), and YPP1 (P46951).
    action: MARK_AS_OVER_ANNOTATED
    reason: >-
      Protein binding is uninformative for a chaperonin subunit. These interactions
      represent chaperonin-substrate relationships that are an inherent part of TRiC/CCT
      function.
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:20489023
  review:
    summary: >-
      IPI evidence from a global protein kinase and phosphatase interaction network.
      TCP1 interacts with SIT4 (P20604).
    action: MARK_AS_OVER_ANNOTATED
    reason: >-
      Protein binding is uninformative for a chaperonin subunit.
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:21701561
  review:
    summary: >-
      IPI evidence from the crystal structure study of yeast CCT. TCP1 interacts with
      ACT1 (P60010) in the CCT-actin co-crystal structure. This is a well-characterized
      chaperonin-substrate interaction.
    action: MARK_AS_OVER_ANNOTATED
    reason: >-
      Protein binding is uninformative. The TCP1-actin interaction is a direct
      chaperonin-substrate relationship, which is the core function of TRiC/CCT
      already captured by the protein folding and complex membership annotations.
    supported_by:
      - reference_id: PMID:21701561
        supporting_text: "We have solved the crystal structure of yeast CCT in complex with actin at 3.8 Å resolution, revealing the subunit organisation and the location of discrete patches of co-evolving 'signature residues' that mediate specific interactions between CCT and its substrates."
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:27107014
  review:
    summary: >-
      IPI evidence from an inter-species protein-protein interaction network. TCP1 interacts
      with several human proteins (cross-species interactions).
    action: MARK_AS_OVER_ANNOTATED
    reason: >-
      Protein binding is uninformative. Cross-species interactions in this context
      likely reflect conserved chaperonin-substrate relationships.
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:37968396
  review:
    summary: >-
      IPI evidence from the social and structural architecture of the yeast protein
      interactome. TCP1 interacts with SIT4 (P20604).
    action: MARK_AS_OVER_ANNOTATED
    reason: >-
      Protein binding is uninformative for a chaperonin subunit.
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:9878052
  review:
    summary: >-
      IPI evidence from the chaperonin-GimC system study (Siegers et al. 1999). TCP1
      interacts with ACT1 (P60010). This study demonstrated that TRiC and GimC form an
      integrated folding compartment that sequesters newly synthesized actin.
    action: MARK_AS_OVER_ANNOTATED
    reason: >-
      Protein binding is uninformative. The TCP1-actin interaction is a core
      chaperonin-substrate relationship already captured by the protein folding and
      complex annotations. The study supports the chaperonin function annotation.
    supported_by:
      - reference_id: PMID:9878052
        supporting_text: "We propose that TRiC and GimC form an integrated 'folding compartment' which functions in cooperation with the translation machinery."
# ============================================================
# IDA ANNOTATIONS (direct experimental evidence)
# ============================================================
- term:
    id: GO:0006457
    label: protein folding
  evidence_type: IDA
  original_reference_id: PMID:16762366
  review:
    summary: >-
      PMID:16762366 demonstrated quantitative actin folding using purified yeast CCT.
      The purified complex catalyses folding of both yeast ACT1p and human beta-actin
      with nearly identical rate constants.
    action: ACCEPT
    reason: >-
      Core biological process. Direct experimental demonstration of TRiC/CCT-mediated
      protein folding in vitro using the purified complex containing TCP1.
    supported_by:
      - reference_id: PMID:16762366
        supporting_text: "Yeast CCT catalyses the folding of yeast ACT1p and human beta-actin with nearly identical rate constants and yields."
- term:
    id: GO:0005886
    label: plasma membrane
  evidence_type: HDA
  original_reference_id: PMID:16622836
  review:
    summary: >-
      HDA evidence from the plasma membrane proteome study. TCP1 was detected in the
      plasma membrane fraction, though this may reflect co-purification rather than
      true membrane localization.
    action: KEEP_AS_NON_CORE
    reason: >-
      TCP1 was detected in the plasma membrane proteome, but TRiC/CCT is primarily
      a cytosolic complex. The plasma membrane association may be a minor or
      artifact localization. Not a core localization.
- term:
    id: GO:0005832
    label: chaperonin-containing T-complex
  evidence_type: IPI
  original_reference_id: PMID:15704212
  review:
    summary: >-
      PMID:15704212 studied physiological effects of unassembled Cct subunits. TCP1
      was shown to be part of the complex through interaction with other subunits
      (with CCT6/S000002596 as supporting entity).
    action: ACCEPT
    reason: >-
      Core complex membership with experimental IPI 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"
- term:
    id: GO:0005832
    label: chaperonin-containing T-complex
  evidence_type: IDA
  original_reference_id: PMID:16762366
  review:
    summary: >-
      PMID:16762366 purified the intact yeast CCT complex, confirming TCP1 as a
      constituent subunit.
    action: ACCEPT
    reason: >-
      Core complex membership with direct experimental evidence from purified complex.
- term:
    id: GO:0051082
    label: unfolded protein binding
  evidence_type: IDA
  original_reference_id: PMID:16762366
  review:
    summary: >-
      GO:0051082 is proposed for obsoletion. PMID:16762366 demonstrated that the purified
      CCT complex binds actin folding intermediates (Ac(I)) and processes them to native
      actin in an ATP-dependent manner. This is chaperonin-mediated folding, not passive
      unfolded protein binding.
    action: MODIFY
    reason: >-
      GO:0051082 is targeted for obsoletion. The experimental evidence from PMID:16762366
      actually demonstrates ATP-dependent protein folding chaperone activity. The CCT complex
      binds actin intermediates in a pre-equilibrium step followed by ATP-driven processing
      to native actin. This is GO:0140662 (ATP-dependent protein folding chaperone).
    proposed_replacement_terms:
      - id: GO:0140662
        label: ATP-dependent protein folding chaperone
    supported_by:
      - reference_id: PMID:16762366
        supporting_text: "The results from this controlled CCT-actin folding assay are consistent with a model where CCT and Ac(I) are in a binding pre-equilibrium with a rate-limiting binding step, followed by a faster ATP-driven processing to native actin."
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: Studied physiological effects of overexpressing individual CCT subunits
      supporting_text: "Overexpression of a single CCT gene in Saccharomyces cerevisiae causes an increase of the corresponding Cct subunit, but not of the Cct complex."
    - statement: Showed that CCT subunits form a stoichiometric array of eight different subunits in two rings
      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:16554755
  title: Global landscape of protein complexes in the yeast Saccharomyces cerevisiae.
  findings: []
- id: PMID:16622836
  title: The plasma membrane proteome of Saccharomyces cerevisiae and its response
    to the antifungal calcofluor.
  findings: []
- id: PMID:16762366
  title: Quantitative actin folding reactions using yeast CCT purified via an internal
    tag in the CCT3/gamma subunit.
  findings:
    - statement: Developed efficient purification protocol for yeast CCT
      supporting_text: "An efficient purification protocol for CCT from Saccharomyces cerevisiae has been developed."
    - statement: Demonstrated quantitative actin folding by purified yeast CCT in vitro
      supporting_text: "Yeast CCT catalyses the folding of yeast ACT1p and human beta-actin with nearly identical rate constants and yields."
    - statement: CCT catalyses folding via a binding pre-equilibrium followed by ATP-driven processing
      supporting_text: "The results from this controlled CCT-actin folding assay are consistent with a model where CCT and Ac(I) are in a binding pre-equilibrium with a rate-limiting binding step, followed by a faster ATP-driven processing to native actin."
- id: PMID:19536198
  title: 'An atlas of chaperone-protein interactions in Saccharomyces cerevisiae:
    implications to protein folding pathways in the cell.'
  findings: []
- id: PMID:20489023
  title: A global protein kinase and phosphatase interaction network in yeast.
  findings: []
- id: PMID:21701561
  title: The crystal structure of yeast CCT reveals intrinsic asymmetry of eukaryotic
    cytosolic chaperonins.
  findings:
    - statement: Solved crystal structure of yeast CCT in complex with actin at 3.8 Å
      supporting_text: "We have solved the crystal structure of yeast CCT in complex with actin at 3.8 Å resolution, revealing the subunit organisation and the location of discrete patches of co-evolving 'signature residues' that mediate specific interactions between CCT and its substrates."
    - statement: Revealed intrinsic asymmetry and subunit individuality in the complex
      supporting_text: "The intrinsic asymmetry is revealed by the structural individuality of the CCT subunits, which display unique configurations, substrate binding properties, ATP-binding heterogeneity and subunit-subunit interactions."
    - statement: CCT uses a sequential rather than concerted ATP hydrolysis mechanism
      supporting_text: "the mechanism by which CCT assists folding is distinct from other chaperonins, with no hydrophobic wall lining a potential Anfinsen cage, and a sequential rather than concerted ATP hydrolysis mechanism."
- id: PMID:27107014
  title: An inter-species protein-protein interaction network across vast evolutionary
    distance.
  findings: []
- id: PMID:37968396
  title: The social and structural architecture of the yeast protein interactome.
  findings: []
- id: PMID:9878052
  title: 'Compartmentation of protein folding in vivo: sequestration of non-native
    polypeptide by the chaperonin-GimC system.'
  findings:
    - statement: TRiC and GimC form an integrated folding compartment for newly synthesized actin
      supporting_text: "We propose that TRiC and GimC form an integrated 'folding compartment' which functions in cooperation with the translation machinery."
    - statement: GimC accelerates actin folding on TRiC at least 5-fold
      supporting_text: "GimC accelerates actin folding at least 5-fold and prevents the premature release of non-native protein from TRiC."
- id: UniProt:P12612
  title: UniProtKB entry for Saccharomyces cerevisiae TCP1/CCT1
  findings:
    - statement: TCP1 encodes CCT-alpha, a member of the TCP-1 chaperonin family.
      supporting_text: "RecName: Full=T-complex protein 1 subunit alpha; Short=TCP-1-alpha; AltName: Full=CCT-alpha;"
- id: file:yeast/TCP1/TCP1-deep-research-falcon.md
  title: Falcon deep research report for yeast TCP1/CCT1
  findings:
    - statement: TCP1/CCT1 is a TRiC/CCT subunit in the cytosolic ATP-dependent chaperonin complex.
      supporting_text: >-
        TCP1/CCT1 encodes CCT1 (TCP-1; CCT-alpha), one of eight paralogous
        subunits that assemble into the eukaryotic cytosolic chaperonin
        TRiC/CCT.
- id: file:interpro/panther/PTHR11353/PTHR11353-metadata.yaml
  title: PANTHER family PTHR11353 chaperonin metadata
  findings:
    - statement: PTHR11353 supports TCP1 as part of the conserved chaperonin family.
      supporting_text: PANTHER family PTHR11353 is named CHAPERONIN and integrates InterPro IPR017998.
core_functions:
  - 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
    description: >-
      TCP1 is the alpha subunit of the TRiC/CCT chaperonin complex. It contributes to the
      complex-level ATP-dependent protein folding chaperone activity (GO:0140662) that folds
      actin, tubulin, and other substrates. Individual subunits do not independently fold
      substrates; the activity emerges from the assembled hetero-oligomeric complex. The
      crystal structure (PMID:21701561) reveals that each subunit has unique configurations
      and substrate-binding properties, suggesting specialized roles within the complex.
      TCP1 binds ATP and contributes ATPase activity to the sequential ATP hydrolysis
      mechanism that drives the chaperonin cycle.
    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_id: PMID:21701561
        supporting_text: "The cytosolic chaperonin CCT is a 1-MDa protein-folding machine essential for eukaryotic life."
      - reference_id: file:yeast/TCP1/TCP1-deep-research-falcon.md
        supporting_text: >-
          TCP1/CCT1 encodes CCT1 (TCP-1; CCT-alpha), one of eight paralogous
          subunits that assemble into the eukaryotic cytosolic chaperonin
          TRiC/CCT. TRiC/CCT is a ~1 MDa ATP-dependent double-ring machine,
          with eight distinct subunits per ring.
      - reference_id: file:interpro/panther/PTHR11353/PTHR11353-metadata.yaml
        supporting_text: PANTHER family PTHR11353 is named CHAPERONIN and supports TCP1/CCT1 membership in the conserved chaperonin family.
proposed_new_terms: []
suggested_questions:
  - question: >-
      Which yeast TRiC/CCT substrates require CCT1-specific apical or
      chamber-facing contacts rather than generic complex-level chaperonin
      activity?
  - question: >-
      Should the emerging nuclear TRiC/CCT RNA polymerase II role be curated for
      TCP1 after peer-reviewed confirmation, or treated as a non-core complex
      phenotype?
suggested_experiments:
  - experiment_type: client-specific folding assay
    hypothesis: >-
      CCT1 contributes substrate-specific contacts that are required for
      efficient folding of selected actin, tubulin, or WD40-repeat clients.
    description: >-
      Combine CCT1 apical/chamber-surface mutants with purified yeast TRiC
      folding assays and in vivo client abundance/activity readouts for ACT1,
      tubulins, Cdh1, and Cdc20.
  - experiment_type: nuclear TRiC validation
    hypothesis: >-
      The nuclear RNA polymerase II phenotype of cct1-2 reflects assembled
      TRiC/CCT function rather than indirect cytoplasmic proteostasis stress.
    description: >-
      Validate nuclear TRiC occupancy and RNAPII/RNA phenotypes using
      independently tagged CCT subunits, acute degron or anchor-away
      perturbations, and rescue with cytoplasm-restricted versus
      nucleus-permissive CCT1 variants.