crt10

UniProt ID: O42996
Organism: Schizosaccharomyces pombe 972h-
Review Status: COMPLETE
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Gene Description

Crt10 (SPBC27B12.05, pi073) is a 482-residue WD-repeat protein of fission yeast that carries a short, weakly conserved Crt10-family region in its C-terminal half and is found in both the nucleus and the cytoplasm. It is the one-to-one counterpart of budding-yeast Crt10, a substrate-targeting accessory subunit that directs the Rtt101-Mms1 cullin-RING ubiquitin ligase to the degradation of nonfunctional 25S ribosomal RNA, and it is therefore inferred to act in nonfunctional large-subunit rRNA decay. The fission-yeast protein is about half the length of its budding-yeast counterpart, and its molecular activity, cullin-ligase partners and direct substrates have not been characterized.

Existing Annotations Review

GO Term Evidence Action Reason
GO:0003674 molecular_function
ND
GO_REF:0000015 		ACCEPT
Summary: The ND molecular-function root correctly records that a specific molecular activity has not been established for fission-yeast Crt10.
Reason: The ND molecular-function root correctly records that a specific molecular activity has not been established for fission-yeast Crt10. Its Crt10/WD-repeat architecture supports an interaction protein, but does not identify a catalytic activity or a particular cullin partner. The gene's search record (notes) finds no study of Crt10 in S. pombe that identifies a molecular function.
Supporting Evidence:
file:SCHPO/crt10/crt10-notes.md
There is no characterized molecular activity in fission yeast.
GO:0005634 nucleus
HDA
PMID:16823372
ORFeome cloning and global analysis of protein localization ... 		ACCEPT
Summary: Nuclear and cytoplasmic localization is supported by the protein-localization study cited in the reviewed UniProt record (PMID:16823372); this is consistent with a nucleo-cytoplasmic RNA-surveillance protein.
Reason: Nuclear and cytoplasmic localization is supported by the protein-localization study cited in the reviewed UniProt record (PMID:16823372); this is consistent with a nucleo-cytoplasmic RNA-surveillance protein. Retain the compartment at the stated resolution.
Supporting Evidence:
file:SCHPO/crt10/crt10-uniprot.txt
CC -!- SUBCELLULAR LOCATION: Cytoplasm {ECO:0000269|PubMed:16823372}. Nucleus CC {ECO:0000269|PubMed:16823372}.
GO:0005634 nucleus
IEA
GO_REF:0000044 		ACCEPT
Summary: Nuclear and cytoplasmic localization is supported by the protein-localization study cited in the reviewed UniProt record (PMID:16823372); this is consistent with a nucleo-cytoplasmic RNA-surveillance protein.
Reason: Nuclear and cytoplasmic localization is supported by the protein-localization study cited in the reviewed UniProt record (PMID:16823372); this is consistent with a nucleo-cytoplasmic RNA-surveillance protein. Retain the compartment at the stated resolution.
Supporting Evidence:
file:SCHPO/crt10/crt10-uniprot.txt
CC -!- SUBCELLULAR LOCATION: Cytoplasm {ECO:0000269|PubMed:16823372}. Nucleus CC {ECO:0000269|PubMed:16823372}.
GO:0005737 cytoplasm
HDA
PMID:22146723
Systematic localization study on novel proteins encoded by m... 		ACCEPT
Summary: PomBase curators recorded a cytoplasmic GFP-localization result for this protein from a mitotic localization survey of 56 meiotically up-regulated, uncharacterized ORFs (PMID:22146723), in which most products were cytoplasmic.
Reason: The cached abstract does not name individual ORFs, but the HDA was made by curators who read the full screen data, and the abstract reports that the majority class of products in this screen was cytoplasmic. The result agrees with the independent ORFeome localization (PMID:16823372) that UniProt cites for cytoplasm and nucleus, so there is no basis to question it. Cytoplasm is as precise as a diffuse GFP signal from this screen warrants; the more specific cytosol term is asserted separately from the ORFeome data.
Supporting Evidence:
PMID:22146723
The remaining 38 proteins were detected in the cytoplasm and showed varied spatial patterns.
file:SCHPO/crt10/crt10-uniprot.txt
CC -!- SUBCELLULAR LOCATION: Cytoplasm {ECO:0000269|PubMed:16823372}. Nucleus CC {ECO:0000269|PubMed:16823372}.
GO:0005737 cytoplasm
IEA
GO_REF:0000044 		ACCEPT
Summary: Nuclear and cytoplasmic localization is supported by the protein-localization study cited in the reviewed UniProt record (PMID:16823372); this is consistent with a nucleo-cytoplasmic RNA-surveillance protein.
Reason: Nuclear and cytoplasmic localization is supported by the protein-localization study cited in the reviewed UniProt record (PMID:16823372); this is consistent with a nucleo-cytoplasmic RNA-surveillance protein. Retain the compartment at the stated resolution.
Supporting Evidence:
file:SCHPO/crt10/crt10-uniprot.txt
CC -!- SUBCELLULAR LOCATION: Cytoplasm {ECO:0000269|PubMed:16823372}. Nucleus CC {ECO:0000269|PubMed:16823372}.
GO:0005829 cytosol
HDA
PMID:16823372
ORFeome cloning and global analysis of protein localization ... 		ACCEPT
Summary: Nuclear and cytoplasmic localization is supported by the protein-localization study cited in the reviewed UniProt record (PMID:16823372); this is consistent with a nucleo-cytoplasmic RNA-surveillance protein.
Reason: Nuclear and cytoplasmic localization is supported by the protein-localization study cited in the reviewed UniProt record (PMID:16823372); this is consistent with a nucleo-cytoplasmic RNA-surveillance protein. Retain the compartment at the stated resolution.
Supporting Evidence:
file:SCHPO/crt10/crt10-uniprot.txt
CC -!- SUBCELLULAR LOCATION: Cytoplasm {ECO:0000269|PubMed:16823372}. Nucleus CC {ECO:0000269|PubMed:16823372}.
GO:0070651 nonfunctional rRNA decay
ISO
GO_REF:0000024 		ACCEPT
Summary: PomBase transfers nonfunctional rRNA decay from budding-yeast Crt10 (SGD:S000005424, UniProt Q08226) by curated one-to-one orthology. In budding yeast Crt10 is the accessory subunit that directs the Rtt101-Mms1 cullin-RING ligase to nonfunctional 25S rRNA decay (PMID:25534857).
Reason: PANTHER does not classify budding-yeast Crt10, so there is no shared PANTHER subfamily or PAINT node behind this transfer, and the PomBase ortholog call is the evolutionary basis. A reciprocal phmmer check supports it. Each yeast proteome has a single PF08728 (CRT10) protein, the non-WD40 C-terminal region of O42996 has budding-yeast Crt10 as its only hit, and Crt10 has O42996 as its only fission-yeast hit (file:SCHPO/crt10/crt10-bioinformatics/RESULTS-rereview.md). The similarity is weak and confined to the Crt10-specific region, and the pombe protein is half the length of Crt10. The transfer is therefore accepted at the pathway level PomBase chose. PomBase did not transfer the budding-yeast ubiquitin-ligase complex membership or the ribonucleotide-reductase transcription phenotypes, and that omission is respected here. Crt10 participates as the targeting subunit that brings the ligase to defective ribosomes, which is direct participation in the decay pathway rather than mere necessity, though this has not been tested in fission yeast.
Supporting Evidence:
PMID:25534857
We herein demonstrated that another accessory component, Crt10 was required for 25S NRD, but not for DNA repair, suggesting that this accessory component specifies the function of the E3 complex differently.
file:SCHPO/crt10/crt10-uniprot.txt
DR Pfam; PF08728; CRT10; 1.
file:SCHPO/crt10/crt10-bioinformatics/RESULTS-rereview.md
O42996 and Q08226 are reciprocal sole matches through the Crt10-specific region, which is consistent with the PomBase one-to-one ortholog assignment.

Core Functions

Crt10-family accessory factor inferred, by one-to-one orthology with budding-yeast Crt10, to act in nonfunctional large-subunit rRNA decay, where the budding-yeast protein targets a cullin-RING ubiquitin ligase to defective 25S rRNA-containing ribosomes. The fission-yeast molecular activity and ligase partners are not established, so no molecular function is asserted.

Directly Involved In:
nonfunctional rRNA decay
Cellular Locations:
cytosol nucleus
Supporting Evidence:
  • PMID:25534857
    We herein demonstrated that another accessory component, Crt10 was required for 25S NRD, but not for DNA repair, suggesting that this accessory component specifies the function of the E3 complex differently.
  • file:SCHPO/crt10/crt10-bioinformatics/RESULTS-rereview.md
    O42996 and Q08226 are reciprocal sole matches through the Crt10-specific region, which is consistent with the PomBase one-to-one ortholog assignment.

References

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Suggested Questions for Experts

Q: Does fission-yeast Crt10 associate with a cullin-RING ligase (for example the Cul4-type cullin Pcu4 and its DDB1-like adaptor) in the way budding-yeast Crt10 associates with Rtt101-Mms1, given that the fission-yeast protein lacks most of the budding-yeast Crt10 sequence?

Q: Is the Crt10-specific C-terminal region (residues about 300-400) sufficient for the function of the protein, or is the WD-repeat region also required?

Suggested Experiments

Experiment: Express a decoding-centre or peptidyl-transferase-centre mutant rRNA in wild-type and crt10 deletion fission yeast and measure the half-life of the mutant rRNA, to test directly whether Crt10 is required for nonfunctional rRNA decay in this species.

Experiment: Affinity-purify tagged Crt10 from fission yeast and identify co-purifying cullin-RING ligase subunits by mass spectrometry.

External Prediction Reviews

These computational predictions are reviewed separately from the GOA annotation set used for this review. The assessments below are from this project and do not constitute official GO annotations or endorsement by GO/UniProt. They are not included in the existing annotation review above.

ProtNLM2 External predictions

View prediction review YAML · crt10-protnlm-predictions-review.yaml · Review status: COMPLETE

Fission-yeast Crt10 is the inferred ortholog of the budding-yeast Rtt101-Mms1 accessory subunit and is annotated to nonfunctional rRNA decay by orthology; neither ProtNLM2 claim (Cul4-RING complex membership, cellular response to UV-B) has experimental or phylogenetic support in fission yeast.

Source documents: genes/SCHPO/crt10/crt10-protnlm-source.xml · genes/SCHPO/crt10/crt10-uniprot-source.json · genes/SCHPO/crt10/crt10-uniprot.txt

Review score: 2 = concordant with evidence; 1 = uncertain; 0 = discordant with evidence. This is an assessment score, not a model probability.

GO:0080008 Cul4-RING E3 ubiquitin ligase complex GO_CC
UNC — Uncertain Review score: 1/2
Prediction method: ProtNLM2 · Version: pre-release post-processed-2026_02_28k.xml · file:SCHPO/crt10/crt10-protnlm-source.xml
Review rationale: Budding-yeast Crt10 co-purifies with the cullin Rtt101 and binds it through the DDB1-like linker Mms1, and Rtt101-Mms1 is described as a CUL4(DDB1)-like ligase. GO, however, represents that assembly as the Cul8-RING ubiquitin ligase complex (GO:0035361), a sibling of the predicted Cul4-RING complex (GO:0080008) under cullin-RING ubiquitin ligase complex, and the budding-yeast review uses the Cul8 term. No study has tested whether fission-yeast Crt10, which is half the length of its budding-yeast counterpart, associates with any cullin ligase, including Pcu4-Ddb1 (Cul4); PubMed has no fission-yeast Crt10 papers. The gene review asserts no complex membership and notes that PomBase did not transfer the budding-yeast ligase-complex membership. The ProtNLM2 claim is a low-scoring phmmer transfer from Arabidopsis WDR5B Q9SY00 (model_score 0.11; phmmer_score 66.0), a WD-repeat protein outside the Crt10 family, so the source does not justify a family transfer. The complex claim is plausible by analogy but neither validated nor refuted.
Supporting Evidence:
  • PMID:25534857: "We herein demonstrated that another accessory component, Crt10 was required for 25S NRD, but not for DNA repair, suggesting that this accessory component specifies the function of the E3 complex differently."
  • PMID:18704118: "Rtt101 interacts in an Mms1-dependent manner with the putative substrate-specific adaptors Mms22 and Crt10"
  • file:SCHPO/crt10/crt10-uniprot.txt: "DR InterPro; IPR014839; Crt10."
GO:0071493 cellular response to UV-B GO_BP
UNC — Uncertain Review score: 1/2
Prediction method: ProtNLM2 · Version: pre-release post-processed-2026_02_28k.xml · file:SCHPO/crt10/crt10-protnlm-source.xml
Review rationale: No experimental annotation or publication links fission-yeast or budding-yeast Crt10 to UV-B responses; PubMed searches for Crt10 with UV or ultraviolet return nothing, and the gene review carries no DNA-damage or radiation-response term. The source is a TMalign structural comparison to Arabidopsis DHU1 Q8GYY7 (model_score 0.11; chain-normalized scores 0.56569 and 0.36277), so shared WD-repeat fold, not a conserved UV-B mechanism, underlies the claim. The characterized budding-yeast Crt10 directs nonfunctional 25S rRNA decay and is dispensable for the DNA-repair function of the Rtt101 ligase, which argues against but does not test a UV-B response. With no target evidence and no justified transfer, the claim is unresolved.
Supporting Evidence:
  • PMID:25534857: "We herein demonstrated that another accessory component, Crt10 was required for 25S NRD, but not for DNA repair, suggesting that this accessory component specifies the function of the E3 complex differently."
  • file:SCHPO/crt10/crt10-uniprot.txt: "DR Pfam; PF08728; CRT10; 1. DR Pfam; PF00400; WD40; 1."

Deep Research

Falcon

(crt10-deep-research-falcon.md)

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📚 Additional Documentation

Notes

(crt10-notes.md)

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📄 View Raw YAML

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