DCV1 (systematic name YFR012W) is a small (202-residue) polytopic integral membrane protein of the budding yeast Saccharomyces cerevisiae. It has an N-terminal signal sequence and three predicted transmembrane helices, and belongs to the fungal Sur7/PalI/Rim9 family of tetraspan membrane proteins (Pfam SUR7 / InterPro SUR7-Rim9-like; PANTHER PTHR28013), which also contains its budding-yeast paralog RIM9 and, by whole-genome duplication, TOS7. Family members are plasma-membrane / eisosome-associated proteins, and several act in the fungal Rim101/PacC ambient-pH signalling pathway; DCV1 has itself been localized to the nuclear envelope. Its own molecular function and biological role are not experimentally established. It is dispensable for viability under standard conditions, and its principal recorded genetic characteristic is a requirement for Cdc28 (Cdk1) activity for viability — the source of its name, "Demands Cdc28 kinase activity for Viability".
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0005886 plasma membrane | IBA GO_REF:0000033 | UNDECIDED | Summary: Inherited localization remains plausible but its target context is unresolved. Reason: Actual PTHR28013 root PTN001997363, carrying plasma-membrane, division-site and growing-tip IBDs, is ancestral to exact DCV1 leaf PTN001997377; no loss was recovered. A short donor list, absence of a target assay and nuclear-envelope localization do not refute inheritance or an additional compartment. Growing-tip GO:0035838 refers to polarized growth at the end of an elongated cell; budding-yeast polarized/elongated states must be evaluated rather than ruled out by taxon. Exact DCV1 images and conditions in PMID:33002606 remain inaccessible here and are requested in focused adjudication. Propagation Review Root cause: UNRESOLVED Sources checked: PANTHER:PTN001997363 UNRESOLVED Actual ancestral IBDs lie on target path. Source assay and target compartment coexistence require adjudication; no demonstrated target loss. |
| GO:0032153 cell division site | IBA GO_REF:0000033 | UNDECIDED | Summary: Inherited localization remains plausible but its target context is unresolved. Reason: Actual PTHR28013 root PTN001997363, carrying plasma-membrane, division-site and growing-tip IBDs, is ancestral to exact DCV1 leaf PTN001997377; no loss was recovered. A short donor list, absence of a target assay and nuclear-envelope localization do not refute inheritance or an additional compartment. Growing-tip GO:0035838 refers to polarized growth at the end of an elongated cell; budding-yeast polarized/elongated states must be evaluated rather than ruled out by taxon. Exact DCV1 images and conditions in PMID:33002606 remain inaccessible here and are requested in focused adjudication. Propagation Review Root cause: UNRESOLVED Sources checked: PANTHER:PTN001997363 UNRESOLVED Actual ancestral IBDs lie on target path. Source assay and target compartment coexistence require adjudication; no demonstrated target loss. |
| GO:0035838 growing cell tip | IBA GO_REF:0000033 | UNDECIDED | Summary: Inherited localization remains plausible but its target context is unresolved. Reason: Actual PTHR28013 root PTN001997363, carrying plasma-membrane, division-site and growing-tip IBDs, is ancestral to exact DCV1 leaf PTN001997377; no loss was recovered. A short donor list, absence of a target assay and nuclear-envelope localization do not refute inheritance or an additional compartment. Growing-tip GO:0035838 refers to polarized growth at the end of an elongated cell; budding-yeast polarized/elongated states must be evaluated rather than ruled out by taxon. Exact DCV1 images and conditions in PMID:33002606 remain inaccessible here and are requested in focused adjudication. Propagation Review Root cause: UNRESOLVED Sources checked: PANTHER:PTN001997363 UNRESOLVED Actual ancestral IBDs lie on target path. Source assay and target compartment coexistence require adjudication; no demonstrated target loss. |
| GO:0005886 plasma membrane | IEA GO_REF:0000002 | UNDECIDED | Summary: Inherited localization remains plausible but its target context is unresolved. Reason: Actual PTHR28013 root PTN001997363, carrying plasma-membrane, division-site and growing-tip IBDs, is ancestral to exact DCV1 leaf PTN001997377; no loss was recovered. A short donor list, absence of a target assay and nuclear-envelope localization do not refute inheritance or an additional compartment. Growing-tip GO:0035838 refers to polarized growth at the end of an elongated cell; budding-yeast polarized/elongated states must be evaluated rather than ruled out by taxon. Exact DCV1 images and conditions in PMID:33002606 remain inaccessible here and are requested in focused adjudication. |
| GO:0016020 membrane | IEA GO_REF:0000044 | ACCEPT | Summary: Membrane is a correct broad description of this integral membrane protein. Reason: The sequence-supported polytopic topology and SGD nuclear-envelope source annotation both support membrane association. A broad parent term is not an over-annotation merely because a more specific compartment term also exists. |
| GO:0005635 nuclear envelope | IDA PMID:33002606 The Sur7/PalI family transmembrane protein Tos7 (Yol019w) pl... | ACCEPT | Summary: Retain the curator-established nuclear-envelope location. Reason: SGD provides target-specific IDA PMID:33002606. Full text remains unavailable after official fetch and publisher/author searches; the title about TOS7 does not establish target misattribution. Defer to the curator for this coherent membrane localization, with source-review uncertainty explicit. A cellular-component annotation can represent a principal location and need not be downgraded simply because it is not a molecular function. It also does not exclude another membrane pool. |
| GO:0003674 molecular_function | ND GO_REF:0000015 | ACCEPT | Summary: Root molecular-function term with ND (No biological Data available). Accurately reflects that no molecular function has been experimentally or computationally established for DCV1. Reason: DCV1 has no assigned enzymatic activity and no demonstrated specific binding partner; the Sur7/PalI family has no known catalytic activity. The ND root annotation is the honest representation of the current state of knowledge and should be retained. |
| GO:0008150 biological_process | ND GO_REF:0000015 | ACCEPT | Summary: Root biological-process term with ND. Accurately reflects that no biological process has been experimentally established for DCV1. Reason: No coherent biological process is demonstrated for DCV1. The recorded characteristics (a synthetic requirement for CDC28 activity, and dispersed high-throughput deletion phenotypes) are genetic/phenotypic observations rather than a defined pathway role. The family-level Rim101 pH-response role of the paralog RIM9 is not established for DCV1. The ND root annotation should be retained. |
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Download this section (compressed HTML)Q: Does DCV1 function in the Rim101/PacC ambient-pH signalling pathway, as its PalI/Rim9 subfamily membership suggests, or has it diverged from that role?
Q: Why is DCV1 required for viability specifically when Cdc28 (Cdk1) activity is limiting, and what does this reveal about a link between a Sur7/PalI membrane protein and the cell cycle?
Q: Is DCV1 functionally redundant with its whole-genome-duplication paralog TOS7?
Experiment: Endogenously tag DCV1 (e.g. C-terminal GFP) and image it against nuclear-envelope/ER and plasma-membrane/eisosome (MCC) markers under standard and alkaline-pH conditions to resolve the conflicting nuclear-envelope (IDA) vs plasma-membrane (IBA/IEA) localizations.
Hypothesis: DCV1 may have condition-dependent nuclear-envelope and plasma-membrane pools; simultaneous compartment markers and endogenous tagging can determine their distribution.
Experiment: Assay dcv1 mutants for Rim101 proteolytic processing and for growth at alkaline pH, and test genetic interactions with RIM9 and other RIM-pathway genes.
Hypothesis: DCV1 contributes to the Rim101 pH-response pathway characteristic of its PalI/Rim9 subfamily.
Experiment: Construct dcv1 tos7 single and double deletions and characterize growth, cell-wall stress sensitivity, secretion, and CDC28-dependence to test paralog redundancy.
Hypothesis: DCV1 and its WGD paralog TOS7 share overlapping functions masked by redundancy in single mutants.
What is not known — curated, literature-grounded statements of the open unknowns (the inverse of core functions).
Gap: The molecular function of DCV1 is unknown. No catalytic activity, transport activity, or specific binding partner has been assigned to DCV1, and the Sur7/PalI/Rim9 family to which it belongs has no defined molecular activity — its members are non-catalytic tetraspan membrane proteins whose scaffolding/sensing role is not captured by any GO molecular-function term. GOA carries only the ND root MF term for DCV1.
OPEN BIOLOGYONTOLOGY WHOLLY_DARK
What is known: DCV1 is firmly established as a 202-residue polytopic integral membrane protein (N-terminal signal peptide plus three transmembrane helices) belonging to the fungal Sur7/PalI/Rim9 family (Pfam SUR7; InterPro IPR009571; PANTHER PTHR28013, subfamily SF3 with the PalI/Rim9 orthologs, including the S. cerevisiae paralog RIM9). Its WGD paralog is TOS7. What is NOT known is any activity the protein performs.
Significance: DCV1 is a conserved-family membrane protein that has never been functionally characterized in its own right. Assigning its activity would clarify whether the budding-yeast Sur7/PalI subfamily has functions beyond the eisosome/pH-response roles known for other members, and a suitable ontology term for non-catalytic tetraspan scaffold/sensor activity would let such functions be expressed at all.
What would resolve it: DCV1-specific biochemistry and interaction mapping (affinity/proximity proteomics, reconstitution) to identify partners or any activity; and, for the ontology gap, a GO molecular-function term for the scaffolding/pH-sensing activity of Sur7/PalI-family tetraspan membrane proteins.
Provenance (the field's own admissions):
Gap: The biological process DCV1 participates in is unknown. Whether DCV1 functions in the Rim101/PacC ambient-pH response pathway (the process characterized for its subfamily relative RIM9), in eisosome/plasma-membrane organization, or in some unrelated process, has not been tested; its only distinctive genetic characteristic is a requirement for Cdc28 (Cdk1) activity for viability, which is a genetic interaction rather than a defined pathway role.
OPEN BIOLOGY BP_DARK
What is known: dcv1 deletion is viable under standard conditions but is lethal/synthetically sick when Cdc28 activity is compromised (the origin of the gene name), and dcv1 was a hit in a genome-wide chemical-genetic screen of the CDC28 network. High-throughput deletion phenotypes are dispersed (altered metal-ion accumulation, MMS sensitivity, reduced chronological lifespan) and do not converge on one process. Membership in the PalI/Rim9 subfamily is suggestive of a pH-response role but is homology-based only.
Significance: A defined process would explain why loss of DCV1 becomes lethal specifically when CDK1 activity is limiting, potentially linking a Sur7/PalI-family membrane protein to cell-cycle robustness — an unexpected connection for this family.
What would resolve it: Test dcv1 for defects in Rim101 processing / alkaline-pH growth and in eisosome/MCC organization; dissect the dcv1-cdc28 genetic interaction (epistasis, suppressors); and test functional redundancy with the paralog TOS7 via a dcv1 tos7 double mutant.
Provenance (the field's own admissions):
Gap: The subcellular localization of DCV1 is not resolved. A single SGD IDA places DCV1 at the nuclear envelope, whereas family/phylogenetic (IBA/IEA) evidence predicts the plasma membrane/eisosome; these have not been reconciled by an independent DCV1-specific study.
OPEN BIOLOGY CC_DARK
What is known: DCV1 is certainly membrane-embedded (three TM helices). The nuclear-envelope assignment rests on one IDA (curated by SGD from PMID:33002606, which I could not verify in full text), while plasma-membrane assignments are homology-based propagations across the Sur7/PalI family.
Significance: Correct localization is a prerequisite for inferring function: a nuclear-envelope/ER protein and a plasma-membrane eisosome protein imply very different roles for DCV1.
What would resolve it: Independent, DCV1-specific localization (endogenously tagged Dcv1 imaged against nuclear envelope/ER and plasma-membrane/eisosome markers) under standard and stress (e.g. alkaline pH) conditions.
Provenance (the field's own admissions):
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