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; DCV1 localizes to the plasma membrane in vegetative cells, is excluded from the pheromone-response front, has also been reported at the nuclear envelope, and is required for normal mating front-rear polarity; it is proposed to act by restricting plasma-membrane lipid distribution. Its molecular activity remains unresolved. 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 | ACCEPT | Summary: Inherited plasma-membrane localization is confirmed by direct Dcv1 imaging. Reason: PTHR28013 root PTN001997363 carries the plasma-membrane IBD on the DCV1 target path, and PMID:36601911 independently demonstrates target-specific Dcv1 localization at the plasma membrane of vegetative budding-yeast cells. The direct target data support the inherited compartment; the is_active_in qualifier remains inherited from the IBD rather than independently demonstrated with a defined Dcv1 molecular activity. The SGD nuclear-envelope IDA from PMID:33002606 therefore represents a second reported compartment or a conditional biosynthetic pool, not evidence against the conserved family plasma-membrane assignment. Propagation Review Root cause: NO FAILURE CORE Sources checked: PANTHER:PTN001997363 SUPPORTS TRANSFER The ancestral plasma-membrane assertion lies on the target path and is supported by direct Dcv1 plasma-membrane imaging. Supporting Evidence: PMID:36601911 Although Dcv1 localized uniformly on the plasma membrane (PM) of vegetative cells, it was confined to the rear of cells responding to pheromone, away from the pheromone receptor. |
| GO:0032153 cell division site | IBA GO_REF:0000033 | UNDECIDED | Summary: Inherited localization remains plausible but its target context is unresolved. Reason: The division-site IBD is on the PTN001997363 path and the source list is not inherently weak, but the focused DCV1 report found no direct Dcv1 enrichment at the budding-yeast bud neck or cytokinesis plane. PMID:36601911 resolves plasma-membrane residence and growing-tip exclusion, but not cell-division-site localization; treat this inherited compartment as unresolved pending direct Dcv1/septin or Dcv1/Myo1 co-imaging. 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 | REMOVE | Summary: Direct pheromone-response imaging argues against inherited growing-tip localization. Reason: The GO:0035838 IBA traces to PTHR28013 fission-yeast tip-localized seeds, but PMID:36601911 tests the closest budding-yeast polarized-growth state and places Dcv1 at the rear of pheromone-responding cells, away from the pheromone receptor and mating front. The target-specific evidence supports plasma-membrane residence while arguing against transfer of the fission-yeast growing-tip compartment to budding-yeast DCV1. Propagation Review Root cause: PROPAGATION BAD Failure modes: COMPARTMENT OR COMPLEX MISMATCH Sources checked: PANTHER:PTN001997363 SUPPORTS SOURCE BUT NOT TARGET The root node carries growing-cell-tip IBDs from fission-yeast descendants, but direct target evidence places Dcv1 away from the budding-yeast pheromone growth front. Supporting Evidence: PMID:36601911 Although Dcv1 localized uniformly on the plasma membrane (PM) of vegetative cells, it was confined to the rear of cells responding to pheromone, away from the pheromone receptor. |
| GO:0005886 plasma membrane | IEA GO_REF:0000002 | ACCEPT | Summary: InterPro plasma-membrane inference is supported by direct Dcv1 imaging. Reason: The SUR7/Rim9 InterPro-to-GO mapping to plasma membrane is appropriate for DCV1: PMID:36601911 directly localized Dcv1 to the plasma membrane in vegetative cells, and the Sur7/PalI family context also points to fungal plasma-membrane domains. Supporting Evidence: PMID:36601911 Although Dcv1 localized uniformly on the plasma membrane (PM) of vegetative cells, it was confined to the rear of cells responding to pheromone, away from the pheromone receptor. |
| 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. PMID:36601911 shows an additional plasma-membrane pool, so the nuclear envelope should be interpreted as a second reported compartment or biosynthetic/conditional pool rather than as evidence against plasma-membrane localization. |
| 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. The gene's own search record (DCV1-deep-research-falcon.md) finds no study of DCV1 in S. cerevisiae that identifies a molecular function. Supporting Evidence: file:yeast/DCV1/DCV1-deep-research-falcon.md There is no evidence that DCV1 is an enzyme or transporter with a defined substrate. |
| GO:0008150 biological_process | ND GO_REF:0000015 | UNDECIDED | Summary: Root biological-process ND is now uncertain after DCV1-specific pheromone-polarity evidence. Reason: PMID:36601911 directly connects Dcv1 to front-rear polarity in pheromone-responding cells and to restriction of plasma-membrane lipid distribution, so the accepted ND root biological-process placeholder may now be stale. This review does not propose a specific BP from the abstract alone; the full paper should be curated for an exact pheromone-response polarity term, and the root placeholder should remain unresolved until that full-text term choice is made. Supporting Evidence: PMID:36601911 dcv1Ξ conferred mislocalization of sensory, polarity and trafficking proteins, as well as PM lipids. These phenotypes correlated with defects in pheromone-gradient tracking and cell fusion. We propose that Dcv1 helps demarcate the mating-specific front domain primarily by restricting PM lipid distribution. |
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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?
Q: Does any endogenously tagged Dcv1 pool enrich at the bud neck or cytokinesis plane, or is the inherited cell-division-site IBA also a fission-yeast localization over-propagated to budding yeast?
Q: What is the exact GO biological-process term for Dcv1-dependent restriction of plasma-membrane lipids during mating front-rear polarity?
Experiment: Endogenously tag DCV1 (e.g. C-terminal GFP) and image it against nuclear-envelope/ER and plasma-membrane/eisosome (MCC) markers under standard, pheromone and alkaline-pH conditions to resolve the nuclear-envelope IDA relative to the directly observed pheromone-responsive plasma-membrane pool.
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.
Experiment: Image endogenously tagged Dcv1 with a septin or Myo1 bud-neck marker throughout the cell cycle to test the inherited cell-division-site localization.
Hypothesis: The PANTHER cell-division-site IBD may reflect fission-yeast source localization that is not inherited by budding-yeast Dcv1.
What is not known β 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 β its members are non-catalytic tetraspan membrane proteins whose scaffolding/sensing role is not captured by any GO molecular-function term. PMID:36601911 establishes a cellular role in plasma-membrane and polarity organization, but not a defined molecular activity.
OPEN BIOLOGYONTOLOGY MF_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 plasma-membrane protein with a demonstrated pheromone-polarity phenotype but no resolved molecular mechanism. Assigning its activity would clarify how a Sur7/PalI-family claudin-like protein restricts plasma-membrane lipid distribution and would show whether this is a scaffolding, sensing or organizing activity.
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 exact GO biological-process term for DCV1's pheromone-response polarity role remains unresolved. PMID:36601911 establishes that Dcv1 influences mating-specific front-rear polarity, pheromone-gradient tracking, cell fusion and plasma-membrane lipid restriction, but the full text should be curated before choosing a specific term and separating direct participation from downstream phenotypes.
NARROWING BIOLOGYCURATION RESIDUAL_SUBGAP
What is known: dcv1 deletion is viable under standard conditions but is lethal/synthetically sick when Cdc28 activity is compromised, and dcv1 was a hit in a genome-wide chemical-genetic screen of the CDC28 network. The DCV1-specific pheromone-polarity phenotype is now the strongest biological-process lead; membership in the PalI/Rim9 subfamily remains only homology-based support for any Rim101 or ambient-pH role.
Significance: A precise process term would connect DCV1 to the mating-cell polarity program without over-reading downstream fusion or gradient-tracking phenotypes as direct functions.
What would resolve it: Read and curate the full PMID:36601911 paper, then test dcv1 for defects in Rim101 processing / alkaline-pH growth; dissect the dcv1-cdc28 genetic interaction by epistasis or suppressors; and test functional redundancy with the paralog TOS7 via a dcv1 tos7 double mutant.
Provenance (the field's own admissions):
Gap: The relationship between DCV1's plasma-membrane pool and its curated nuclear-envelope pool remains unresolved. PMID:36601911 establishes plasma-membrane localization in vegetative and pheromone-responding cells, while SGD curates a nuclear-envelope IDA from PMID:33002606 whose full text is still not cached.
NARROWING BIOLOGY RESIDUAL_SUBGAP
What is known: DCV1 is certainly membrane-embedded, and plasma-membrane localization is now directly supported for Dcv1. What remains unknown is whether the nuclear-envelope signal represents a functional second location, a biosynthetic/ER pool of a secretory-pathway membrane protein, or a construct-specific condition in the Tos7-focused paper.
Significance: The plasma membrane is directly supported, but the nuclear-envelope evidence should be reconciled before deciding whether DCV1 has a condition-specific nuclear-envelope function.
What would resolve it: Read the full PMID:33002606 source and image endogenously tagged Dcv1 against nuclear-envelope/ER, plasma-membrane/eisosome and bud-neck markers under standard, pheromone and alkaline-pH conditions.
Provenance (the field's own admissions):
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Download this section (compressed HTML)Protein of unknown function; deletion mutant shows strong genetic interaction with cdc28-as1 mutant in the presence of 1-NM-PP1; DCV1 has a paralog, YOL019W, that arose from the whole genome duplication
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