Pom1 is a DYRK-family dual-specificity protein kinase that acts as a spatial cell-end marker in fission yeast. It forms a concentration gradient on the plasma membrane that is highest at the cell tips and lowest at mid-cell. Pom1 is recruited to the cortex at cell tips by the Tea1-Tea4/Mod5 microtubule-based landmark system; Tea4-promoted dephosphorylation (via protein phosphatase 1 Dis2) drives membrane association, while intermolecular autophosphorylation in a membrane-binding basic region lowers lipid affinity and releases Pom1, shaping and buffering the gradient. Pom1 autophosphorylates on tyrosine and phosphorylates substrates on serine/threonine. Through this gradient Pom1 couples cell geometry to two main outputs: it times mitotic entry as part of cell-size control by inhibiting the medial SAD-family kinase Cdr2 (and Cdr1), which otherwise inhibit Wee1; and it positions the cytokinetic division plane at mid-cell by restricting Mid1 distribution and by phosphorylating the F-BAR protein Cdc15 to prevent septum assembly at cell ends. Pom1 also promotes the activation of bipolar growth (NETO) and cell polarity, in part by controlling the localization and phosphorylation of the Cdc42 GAP Rga4 to ensure bipolar activation of Cdc42.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0005737 cytoplasm | IBA GO_REF:0000033 | KEEP AS NON CORE | Summary: Phylogenetic (IBA) annotation to the broad cytoplasm term. Pom1 is a peripheral plasma-membrane/cell-cortex protein that forms gradients emanating from cell tips, so this term is not wrong but is uninformative and far less specific than the experimentally supported cortical/membrane locations. Keep as non-core. Reason: Too general; the informative, experimentally supported localizations are cell cortex of cell tip, plasma membrane, and site of polarized growth. |
| GO:0005856 cytoskeleton | IBA GO_REF:0000033 | REMOVE | Summary: Phylogenetic (IBA) annotation. There is no experimental evidence that Pom1 is a structural component of the cytoskeleton; it is a cortical/plasma membrane kinase whose localization depends on microtubules and the Tea1-Tea4 landmark system but that does not make it a cytoskeletal component. This appears to be an over-annotation propagated from the PANTHER family. Reason: Pom1 localizes to the cell cortex and plasma membrane, not the cytoskeleton; microtubule dependence of its delivery does not justify a cytoskeleton location annotation. Propagation Review Root cause: PROPAGATION BAD Failure modes: COMPARTMENT OR COMPLEX MISMATCH Sources checked: PANTHER:PTN008603465 SUPPORTS SOURCE BUT NOT TARGET The deep DYRK-family node combines compartmentally divergent paralogs; cytoskeleton-associated evidence does not transfer to the peripheral cortical Pom1 subfamily. |
| GO:0004672 protein kinase activity | IEA GO_REF:0000002 | KEEP AS NON CORE | Summary: InterPro-based electronic annotation of generic protein kinase activity. Correct but superseded by the experimentally supported, more specific dual-specificity activities (protein serine/threonine kinase activity and protein tyrosine kinase activity). Keep as non-core parent term. Reason: Subsumed by more specific, experimentally supported MF terms. Supporting Evidence: PMID:11230130 Pom1p kinase activity is cell cycle regulated and essential for cellular symmetry during growth and division. |
| GO:0004712 protein serine/threonine/tyrosine kinase activity | IEA GO_REF:0000120 | ACCEPT | Summary: Electronic annotation (from EC 2.7.12.1) capturing the dual-specificity nature of Pom1. This is accurate: Pom1 is a DYRK-family kinase that autophosphorylates on tyrosine and phosphorylates exogenous substrates on serine/threonine. This combined term, or the pair of specific Ser/Thr and Tyr terms, represents the core molecular function. Reason: Accurately captures the dual-specificity (Ser/Thr + Tyr) catalytic activity of this DYRK-family kinase. Supporting Evidence: PMID:22174761 autophosphorylation on tyrosine and exogenous phosphorylation on serine/threonine residues. |
| GO:0004713 protein tyrosine kinase activity | IEA GO_REF:0000116 | ACCEPT | Summary: Rhea-based electronic annotation. Pom1 is a DYRK-family kinase that autophosphorylates on tyrosine; tyrosine kinase activity (limited largely to autophosphorylation) is part of its dual-specificity catalytic function. Supported experimentally as well (see EXP annotations). Core MF. Reason: Tyrosine (auto)phosphorylation is an established feature of DYRK-family kinases including Pom1. Supporting Evidence: PMID:22174761 autophosphorylation on tyrosine and exogenous phosphorylation on serine/threonine residues. |
| GO:0005524 ATP binding | IEA GO_REF:0000002 | ACCEPT | Summary: InterPro-based annotation of ATP binding. Consistent with the canonical protein kinase domain (residues 699-995) with an ATP-binding glycine-rich loop (705-713) and invariant lysine (K728). Standard, correct supporting MF for a kinase. Reason: Pom1 has a conserved protein kinase domain with characterized ATP-binding residues; ATP binding is required for its catalytic activity. |
| GO:0005886 plasma membrane | IEA GO_REF:0000044 | ACCEPT | Summary: Electronic annotation from the UniProt subcellular location vocabulary. Pom1 is a peripheral plasma-membrane protein that binds membrane lipids through a basic region; this is strongly supported experimentally (PMID:21703453). Core location. Reason: Pom1 directly binds plasma-membrane lipids and forms gradients on the plasma membrane. Supporting Evidence: PMID:21703453 binds through a basic region exhibiting direct lipid interaction. |
| GO:0051286 cell tip | IEA GO_REF:0000044 | ACCEPT | Summary: Electronic annotation from the UniProt subcellular location vocabulary; redundant with multiple experimental cell tip annotations below. Cell tip localization is a defining feature of Pom1 (highest gradient concentration). Core location. Reason: Cell tip enrichment is the hallmark localization of Pom1, supported by many experimental studies. Supporting Evidence: PMID:11230130 Pom1p localization to cell ends. |
| GO:0106310 protein serine kinase activity | IEA GO_REF:0000116 | ACCEPT | Summary: Rhea-based electronic annotation; redundant with EXP-supported Ser/Thr kinase annotations. Pom1 phosphorylates substrates on Ser/Thr residues. Core MF. Reason: Serine phosphorylation of substrates is the principal catalytic output of Pom1. Supporting Evidence: PMID:25720772 Purified Pom1 phosphorylated these cell polarity targets in vitro, confirming that they are direct substrates of Pom1 kinase activity and likely contribute to regulation of polarized growth by Pom1. |
| GO:0005515 protein binding | IPI PMID:19474792 Polar gradients of the DYRK-family kinase Pom1 couple cell l... | REMOVE | Summary: IPI annotation to the uninformative generic 'protein binding' term, based on the physical interaction with Cdr2. The interaction is real and biologically important (Pom1 phosphorylates Cdr2), but 'protein binding' conveys no functional information; the relationship is better captured by Pom1's kinase activity acting on Cdr2 in cell-size control. Reason: Bare 'protein binding' is uninformative; the Cdr2 relationship is captured by kinase activity and the G2/M cell-size-control process terms. |
| GO:0005515 protein binding | IPI PMID:21703453 A phosphorylation cycle shapes gradients of the DYRK family ... | REMOVE | Summary: IPI annotation to generic 'protein binding' based on the Pom1-Tea4 interaction. Tea4 binding is functionally important (it triggers Pom1 membrane recruitment), but the bare term is uninformative. The relationship is better represented by Pom1's membrane localization and the Tea4-dependent recruitment mechanism. Reason: Bare 'protein binding' is uninformative; the Tea4 interaction is captured by the membrane-association mechanism and localization terms. |
| GO:1903500 negative regulation of mitotic actomyosin contractile ring assembly | IMP PMID:36749320 Multiple polarity kinases inhibit phase separation of F-BAR ... | ACCEPT | Summary: IMP annotation supported by work showing that multiple polarity kinases, including Pom1, phosphorylate the F-BAR protein Cdc15 to inhibit its phase separation/condensation on the plasma membrane and thereby antagonize contractile-ring assembly (preventing ring assembly at cell tips). This is a well-supported, functionally specific process for Pom1. Reason: Pom1 phosphorylation of Cdc15 limits Cdc15 condensation and antagonizes contractile-ring assembly at inappropriate (tip) locations. Supporting Evidence: PMID:36749320 phosphorylation by assorted kinases prevents Cdc15 condensation on the PM and antagonizes CR assembly. |
| GO:0004713 protein tyrosine kinase activity | EXP PMID:19474792 Polar gradients of the DYRK-family kinase Pom1 couple cell l... | ACCEPT | Summary: Experimentally supported tyrosine kinase activity, consistent with Pom1 being a DYRK-family kinase that autophosphorylates on tyrosine. Core MF. Reason: Direct experimental support for the dual-specificity (tyrosine autophosphorylation) activity of Pom1. Supporting Evidence: PMID:22174761 autophosphorylation on tyrosine and exogenous phosphorylation on serine/threonine residues. |
| GO:0004713 protein tyrosine kinase activity | EXP PMID:24508166 Dueling kinases regulate cell size at division through the S... | ACCEPT | Summary: Experimentally supported tyrosine kinase activity (dual-specificity DYRK). Redundant with the other tyrosine kinase annotations; core MF. Reason: Supports the dual-specificity catalytic function of Pom1. Supporting Evidence: PMID:22174761 autophosphorylation on tyrosine and exogenous phosphorylation on serine/threonine residues. |
| GO:0004713 protein tyrosine kinase activity | EXP PMID:25720772 Quantitative phosphoproteomics reveals pathways for coordina... | ACCEPT | Summary: Experimentally supported tyrosine kinase activity from quantitative phosphoproteomics characterization of Pom1. Redundant with other tyrosine kinase annotations; core MF. Reason: Supports the dual-specificity catalytic function of Pom1. Supporting Evidence: PMID:22174761 autophosphorylation on tyrosine and exogenous phosphorylation on serine/threonine residues. |
| GO:0051286 cell tip | EXP PMID:11230130 Fission yeast Pom1p kinase activity is cell cycle regulated ... | ACCEPT | Summary: Experimentally supported cell tip localization; Pom1 requires its kinase activity and non-catalytic domain to localize to cell ends. Core location. Reason: Cell tip (cell end) localization is directly demonstrated. Supporting Evidence: PMID:11230130 Pom1p is present in a large protein complex and requires its non-catalytic domain to localize to the cell periphery and its kinase activity to localize to cell ends. |
| GO:0051286 cell tip | EXP PMID:11950884 Different mechanisms of cell polarisation in vegetative and ... | ACCEPT | Summary: Experimentally supported cell tip localization (vegetative vs shmooing growth study). The cached abstract directly reports that the analyzed morphological factors, including Pom1, concentrate at cell ends during vegetative growth. Core location. Reason: The source abstract directly supports cell-end localization and independent Pom1 studies corroborate the same cortical-tip distribution. Supporting Evidence: PMID:11950884 In vegetative growth these morphological factors are concentrated at cell ends, whereas during shmooing growth they are delocalised from the cell ends. |
| GO:0051286 cell tip | EXP PMID:14663827 Role of Tea1p, Tea3p and Pom1p in the determination of cell ... | ACCEPT | Summary: Experimentally supported cell tip localization from the study of cell-end determination by Tea1/Tea3/Pom1. Core location. Reason: Cell tip localization directly observed in cell-end determination study. Supporting Evidence: PMID:14663827 has the greatest difficulty in relocalizing actin to the cell ends following actin depolymerization and generates the most defective growth pattern. |
| GO:0106310 protein serine kinase activity | EXP PMID:19474792 Polar gradients of the DYRK-family kinase Pom1 couple cell l... | ACCEPT | Summary: Experimentally supported serine/threonine kinase activity; Pom1 phosphorylates substrates including Cdr2 on Ser/Thr residues. Core MF. Reason: Serine phosphorylation of substrates is a core catalytic output of Pom1. Supporting Evidence: PMID:25720772 Purified Pom1 phosphorylated these cell polarity targets in vitro, confirming that they are direct substrates of Pom1 kinase activity and likely contribute to regulation of polarized growth by Pom1. |
| GO:0106310 protein serine kinase activity | EXP PMID:24508166 Dueling kinases regulate cell size at division through the S... | ACCEPT | Summary: Experimentally supported Ser/Thr kinase activity; Pom1 phosphorylates the C-terminal domain of Cdr2 to inhibit its activation. Core MF. Reason: Direct phosphorylation of Cdr2 demonstrates Ser/Thr kinase activity. Supporting Evidence: PMID:24508166 prevent activation of Cdr2 kinase activity by the CaMKK Ssp1. |
| GO:0106310 protein serine kinase activity | EXP PMID:25720772 Quantitative phosphoproteomics reveals pathways for coordina... | ACCEPT | Summary: Experimentally supported Ser/Thr kinase activity from quantitative phosphoproteomics; purified Pom1 directly phosphorylates polarity substrates in vitro. Core MF. Reason: Direct in vitro phosphorylation of substrates demonstrates Ser/Thr kinase activity. Supporting Evidence: PMID:25720772 Purified Pom1 phosphorylated these cell polarity targets in vitro, confirming that they are direct substrates of Pom1 kinase activity and likely contribute to regulation of polarized growth by Pom1. |
| GO:0005886 plasma membrane | EXP PMID:21703453 A phosphorylation cycle shapes gradients of the DYRK family ... | ACCEPT | Summary: Experimentally supported plasma membrane localization/activity. Tea4 recruits Pom1 to the cortex, where it binds plasma-membrane lipids via a basic region and moves laterally, forming the tip-to-middle gradient. Core location. Reason: Pom1 directly binds and acts at the plasma membrane. Supporting Evidence: PMID:21703453 binds through a basic region exhibiting direct lipid interaction. |
| GO:0032956 regulation of actin cytoskeleton organization | IMP PMID:14663827 Role of Tea1p, Tea3p and Pom1p in the determination of cell ... | KEEP AS NON CORE | Summary: IMP annotation. pom1 mutants (especially with tea1 or tea3) show the greatest defect in relocalizing actin to cell ends after depolarization. Pom1 influences actin organization indirectly through its control of cell polarity and Cdc42 activation rather than as a direct actin regulator; reasonable to keep as a non-core, downstream process. Reason: Effect on actin organization is an indirect consequence of Pom1's role in polarity/Cdc42 regulation, not a direct core function. Supporting Evidence: PMID:14663827 has the greatest difficulty in relocalizing actin to the cell ends following actin depolymerization and generates the most defective growth pattern. |
| GO:0051285 cell cortex of cell tip | EXP PMID:37746062 Polarity kinases that phosphorylate F-BAR protein Cdc15 have... | ACCEPT | Summary: Experimentally supported cortex-of-cell-tip localization during cytokinesis, from a study of polarity kinases that phosphorylate Cdc15 and prevent tip septation. This specific cortical location is the most informative CC term for Pom1. Core location. Reason: Directly observed cortex-of-cell-tip localization; most specific accurate CC term. Supporting Evidence: PMID:37746062 preventing tip septation in Schizosaccharomyces pombe. |
| GO:0004674 protein serine/threonine kinase activity | IDA PMID:36749320 Multiple polarity kinases inhibit phase separation of F-BAR ... | ACCEPT | Summary: IDA Ser/Thr kinase activity; Pom1 directly phosphorylates the F-BAR protein Cdc15 to inhibit its condensation and antagonize ring assembly. Core MF. Reason: Direct phosphorylation of Cdc15 demonstrates Ser/Thr kinase activity. Supporting Evidence: PMID:36749320 phosphorylation by assorted kinases prevents Cdc15 condensation on the PM and antagonizes CR assembly. |
| GO:0030950 establishment or maintenance of actin cytoskeleton polarity | IMP PMID:11950884 Different mechanisms of cell polarisation in vegetative and ... | KEEP AS NON CORE | Summary: IMP annotation linking Pom1 to actin cytoskeleton polarity during vegetative growth. As with regulation of actin organization, this reflects Pom1's role as an upstream polarity determinant rather than a direct actin effector. Keep as non-core. Reason: Downstream/indirect consequence of Pom1's polarity function; not a direct core molecular role. Supporting Evidence: PMID:9573052 most cells never switch to bipolar growth but instead grow exclusively at the randomly chosen end. |
| GO:0097575 lateral cell cortex | IDA PMID:26443240 PKA antagonizes CLASP-dependent microtubule stabilization to... | KEEP AS NON CORE | Summary: IDA annotation. Under glucose limitation Pom1 re-localizes from cell tips to the cell sides (lateral cell cortex), where it delays mitosis. This is a genuine condition-specific localization but represents a stress response rather than the steady-state core localization. Keep as non-core. Reason: Lateral cortex localization is a glucose-limitation/stress-specific redistribution, not the core tip-enriched localization. Supporting Evidence: PMID:26443240 cell sides upon environmental glucose limitation, where it strongly delays mitosis. |
| GO:1903138 negative regulation of cell integrity MAPK cascade | IMP PMID:20164182 Rga4 modulates the activity of the fission yeast cell integr... | KEEP AS NON CORE | Summary: IMP annotation. Pom1 is a negative regulator of the Pmk1 cell-integrity MAPK pathway, acting through its control of Rga4 localization and phosphorylation (independent of Rga4's Rho2-GAP role). This is a genuine but peripheral/indirect process for Pom1. Keep as non-core. Reason: Real but indirect regulatory role downstream of Pom1's control of Rga4; not a core function. Supporting Evidence: PMID:20164182 is also a negative regulator of the Pmk1 pathway, but this control is not dependent upon the Rga4 role as a Rho2-GAP. |
| GO:0004674 protein serine/threonine kinase activity | IDA PMID:32101481 DYRK kinase Pom1 drives F-BAR protein Cdc15 from the membran... | ACCEPT | Summary: IDA Ser/Thr kinase activity; Pom1 phosphorylates the F-BAR protein Cdc15 to drive it from the membrane and ensure medial division. Core MF. Reason: Direct phosphorylation of Cdc15 demonstrates Ser/Thr kinase activity. Supporting Evidence: PMID:32101481 kinase activity prevents septation at cell tips even if Mid1 is absent or mislocalized. |
| GO:0005515 protein binding | IPI PMID:18328707 Pom1 DYRK regulates localization of the Rga4 GAP to ensure b... | REMOVE | Summary: IPI annotation to generic 'protein binding' based on the Pom1-Rga4 physical interaction. The interaction is functionally important (Pom1 regulates Rga4 localization/phosphorylation), but the bare term is uninformative; the relationship is captured by Pom1 kinase activity and its role in bipolar Cdc42 activation/cell polarity. Reason: Bare 'protein binding' is uninformative; the Rga4 relationship is captured by kinase activity and cell polarity process terms. |
| GO:0051518 positive regulation of bipolar cell growth | IMP PMID:18328707 Pom1 DYRK regulates localization of the Rga4 GAP to ensure b... | ACCEPT | Summary: IMP annotation. Pom1 promotes the new-end take-off (NETO) to bipolar growth; pom1 deletion causes monopolar growth. Mechanistically Pom1 ensures bipolar localization of active Cdc42 by controlling the Cdc42 GAP Rga4. Well supported core process. Reason: Pom1 is required for activation of bipolar growth, acting via Rga4/Cdc42. Supporting Evidence: PMID:18328707 is essential for proper localization of a GAP for Cdc42, Rga4, which ensures bipolar localization of GTP-bound, active Cdc42. |
| GO:0061245 establishment or maintenance of bipolar cell polarity | IGI PMID:29930085 Local and global Cdc42 guanine nucleotide exchange factors f... | ACCEPT | Summary: IGI annotation. The Tea1-Tea4-Pom1 axis, together with microtubules, counteracts inappropriate Gef1 activity by regulating Rga4 localization, coordinating local and global Cdc42 GEFs for bipolar polarity. Core process for Pom1. Reason: Pom1, within the Tea1-Tea4-Pom1 axis, establishes bipolar cell polarity by coordinating Cdc42 regulators. Supporting Evidence: PMID:29930085 Tea1-Tea4-Pom1 axis counteract inappropriate Gef1 activity by regulating the localization of the Cdc42 GTPase-activating protein Rga4. |
| GO:0031569 mitotic G2 cell size control checkpoint signaling | EXP PMID:29514920 Cell size-dependent regulation of Wee1 localization by Cdr2 ... | ACCEPT | Summary: Experimentally supported. Pom1 contributes to size-dependent signaling by suppressing Wee1 node bursts in small cells (acting as a Cdr2 inhibitor), coupling cell size to mitotic entry. Core process. Reason: Pom1 mediates cell-size-dependent regulation of Wee1 localization via Cdr2 inhibition. Supporting Evidence: PMID:29514920 Size-dependent signaling was caused in part by the Cdr2 inhibitor Pom1, which suppressed Wee1 node bursts in small cells. |
| GO:0010972 negative regulation of G2/M transition of mitotic cell cycle | IMP PMID:24047646 Pom1 and cell size homeostasis in fission yeast. | ACCEPT | Summary: IMP annotation. Pom1 acts as a dose-dependent inhibitor of mitotic entry. Note that this study found pom1-deleted cells still show normal size homeostasis, arguing Pom1 is not the sole/direct cell-size sensor; however its role as a negative regulator of the G2/M transition is well established. Core process. Reason: Pom1 delays G2/M transition; established negative regulator of mitotic entry even though it is not the unique size sensor. Supporting Evidence: PMID:24047646 show wild-type size homeostasis both in size variability analyses and size homeostasis experiments. |
| GO:0032153 cell division site | EXP PMID:24047646 Pom1 and cell size homeostasis in fission yeast. | ACCEPT | Summary: Experimentally supported localization to the cell division site, where Pom1 contributes to division-plane positioning and prevention of inappropriate septation. Core location. Reason: Pom1 localizes to and acts at the cell division site. Supporting Evidence: PMID:9852154 Pom1p is required for proper placement of the Mid1p ring. |
| GO:0051286 cell tip | EXP PMID:24047646 Pom1 and cell size homeostasis in fission yeast. | ACCEPT | Summary: Experimentally supported cell tip localization (cell-size homeostasis study). Redundant with other cell tip annotations; core location. Reason: Cell tip localization repeatedly demonstrated for Pom1. Supporting Evidence: PMID:11230130 Pom1p localization to cell ends. |
| GO:0004674 protein serine/threonine kinase activity | EXP PMID:29249658 Mechanisms Connecting the Conserved Protein Kinases Ssp1, Ki... | ACCEPT | Summary: Experimentally supported Ser/Thr kinase activity within the Ssp1-Kin1-Pom1 polarity/division network. Core MF. Reason: Supports Pom1's Ser/Thr kinase activity in polarity and division control. Supporting Evidence: PMID:25720772 Purified Pom1 phosphorylated these cell polarity targets in vitro, confirming that they are direct substrates of Pom1 kinase activity and likely contribute to regulation of polarized growth by Pom1. |
| GO:0120105 mitotic actomyosin contractile ring, intermediate layer | IDA PMID:28914606 Nanoscale architecture of the Schizosaccharomyces pombe cont... | KEEP AS NON CORE | Summary: IDA from a nanoscale super-resolution architecture map placing Pom1 among signaling components in the intermediate layer of the contractile ring. This is a fine-grained, structurally-defined location consistent with Pom1's role in regulating ring assembly/positioning, but it is a specialized localization rather than Pom1's core tip-gradient role. Reason: Specialized contractile-ring sublayer localization; peripheral to the core tip-gradient function, though consistent with Pom1's cytokinesis role. Supporting Evidence: PMID:28914606 intermediate layer (80-160 nm) consists of a network of cytokinesis accessory proteins as well as multiple signaling components which influence cell division. |
| GO:0004674 protein serine/threonine kinase activity | EXP PMID:19474789 A spatial gradient coordinates cell size and mitotic entry i... | ACCEPT | Summary: Experimentally supported Ser/Thr kinase activity in the spatial gradient / cell-size coordination study. Core MF. Reason: Supports Pom1's Ser/Thr kinase activity acting on the Cdr2 pathway. Supporting Evidence: PMID:25720772 Purified Pom1 phosphorylated these cell polarity targets in vitro, confirming that they are direct substrates of Pom1 kinase activity and likely contribute to regulation of polarized growth by Pom1. |
| GO:0004674 protein serine/threonine kinase activity | IMP PMID:19474792 Polar gradients of the DYRK-family kinase Pom1 couple cell l... | ACCEPT | Summary: Kinase activity inferred from mutant phenotype (catalytically relevant mutations) in the gradient/cell-length-coupling study. Consistent with the well-established Ser/Thr kinase activity. Core MF. Reason: Pom1 kinase activity required for cell-length coupling to mitotic entry. Supporting Evidence: PMID:19474792 Pom1 is also a dose-dependent G2-M inhibitor. |
| GO:0010972 negative regulation of G2/M transition of mitotic cell cycle | IMP PMID:19474792 Polar gradients of the DYRK-family kinase Pom1 couple cell l... | ACCEPT | Summary: IMP annotation. Pom1 is a dose-dependent G2-M inhibitor that negatively regulates Cdr1/Cdr2 (Wee1 inhibitors); as cells elongate, mid-cell Pom1 declines, releasing the inhibition and permitting mitotic entry. Core process. Reason: Central, well-supported role of Pom1 as a negative regulator of the G2/M transition. Supporting Evidence: PMID:19474792 Pom1 is also a dose-dependent G2-M inhibitor. |
| GO:0051285 cell cortex of cell tip | IDA PMID:19474792 Polar gradients of the DYRK-family kinase Pom1 couple cell l... | ACCEPT | Summary: IDA cortex-of-cell-tip localization; this is the most specific accurate CC term, capturing the tip-enriched cortical gradient. Core location. Reason: Directly observed tip cortical localization underlying the Pom1 gradient. Supporting Evidence: PMID:19474792 emanates from the ends of rod-shaped Schizosaccharomyces pombe cells, serves to measure cell length and control mitotic entry. |
| GO:1903067 negative regulation of protein localization to cell tip | IMP PMID:19474792 Polar gradients of the DYRK-family kinase Pom1 couple cell l... | ACCEPT | Summary: IMP annotation. Pom1 restricts Cdr2 distribution away from cell tips, limiting Cdr2 to a medial band. This specific spatial-regulation process is well supported and mechanistically important for size control. Accept. Reason: Pom1 negatively regulates the cortical distribution/localization of Cdr2 toward cell tips. Supporting Evidence: PMID:24316795 Pom1 inhibits Cdr2 for mitotic commitment independently of regulating its localization or cortical levels. |
| GO:0031569 mitotic G2 cell size control checkpoint signaling | IMP PMID:19474789 A spatial gradient coordinates cell size and mitotic entry i... | ACCEPT | Summary: IMP annotation. Pom1 forms a polar gradient acting as a dose-dependent inhibitor of mitotic entry working through the Cdr2 pathway, coordinating cell size with mitotic entry. Core process. Reason: Pom1 couples cell size to mitotic entry via the Cdr2 pathway. Supporting Evidence: PMID:19474789 Pom1 forms a polar gradient extending from the cell ends towards the cell middle and acts as a dose-dependent inhibitor of mitotic entry, working through the Cdr2 pathway. |
| GO:0004674 protein serine/threonine kinase activity | IDA PMID:21703453 A phosphorylation cycle shapes gradients of the DYRK family ... | ACCEPT | Summary: IDA Ser/Thr kinase activity; Pom1 autophosphorylates in its membrane- binding region (and phosphorylates substrates). Core MF. Reason: Pom1 autophosphorylation/substrate phosphorylation demonstrates Ser/Thr kinase activity. Supporting Evidence: PMID:21703453 Pom1 autophosphorylates in this region to lower lipid affinity and promote membrane release. |
| GO:0004674 protein serine/threonine kinase activity | IDA PMID:26150232 Pom1 gradient buffering through intermolecular auto-phosphor... | ACCEPT | Summary: IDA Ser/Thr kinase activity; Pom1 autophosphorylates intermolecularly to buffer the gradient. Core MF. Reason: Intermolecular autophosphorylation demonstrates kinase activity. Supporting Evidence: PMID:26150232 auto-phosphorylates intermolecularly. |
| GO:1901981 phosphatidylinositol phosphate binding | IDA PMID:21703453 A phosphorylation cycle shapes gradients of the DYRK family ... | ACCEPT | Summary: IDA annotation. Pom1 binds plasma-membrane lipids through a basic region exhibiting direct lipid interaction, and autophosphorylation in this region reduces lipid affinity. This lipid-binding activity is integral to Pom1's membrane association and gradient formation. Core MF. Reason: Direct lipid (phosphoinositide) binding via a basic region underlies Pom1's plasma-membrane association. Supporting Evidence: PMID:21703453 binds through a basic region exhibiting direct lipid interaction. |
| GO:1903077 negative regulation of protein localization to plasma membrane | IMP PMID:21703453 A phosphorylation cycle shapes gradients of the DYRK family ... | KEEP AS NON CORE | Summary: IMP annotation. Pom1 autophosphorylation lowers its own lipid affinity and promotes membrane release, negatively regulating membrane association as part of the gradient-shaping phosphorylation cycle. Accept as a specific mechanism, though it primarily reflects autoregulation. Reason: Captures Pom1's autoregulatory membrane release; mechanistically real but a sub-aspect of the core gradient-formation function. Supporting Evidence: PMID:21703453 Pom1 autophosphorylates in this region to lower lipid affinity and promote membrane release. |
| GO:0051285 cell cortex of cell tip | IDA PMID:21703453 A phosphorylation cycle shapes gradients of the DYRK family ... | ACCEPT | Summary: IDA cortex-of-cell-tip localization; Tea4 recruits Pom1 to the tip cortex where it associates with the plasma membrane and forms the gradient. Most specific accurate CC term. Core location. Reason: Directly observed tip cortical localization. Supporting Evidence: PMID:21703453 binds through a basic region exhibiting direct lipid interaction. |
| GO:0004674 protein serine/threonine kinase activity | IDA PMID:25720772 Quantitative phosphoproteomics reveals pathways for coordina... | ACCEPT | Summary: IDA Ser/Thr kinase activity from quantitative phosphoproteomics; purified Pom1 directly phosphorylates multiple polarity substrates in vitro. Core MF. Reason: Direct in vitro substrate phosphorylation demonstrates Ser/Thr kinase activity. Supporting Evidence: PMID:25720772 Purified Pom1 phosphorylated these cell polarity targets in vitro, confirming that they are direct substrates of Pom1 kinase activity and likely contribute to regulation of polarized growth by Pom1. |
| GO:1903077 negative regulation of protein localization to plasma membrane | IDA PMID:26150232 Pom1 gradient buffering through intermolecular auto-phosphor... | KEEP AS NON CORE | Summary: IDA annotation. Intermolecular autophosphorylation by Pom1 promotes its own membrane release, negatively regulating membrane localization and buffering the gradient. As above, a sub-aspect of gradient formation. Reason: Autoregulatory membrane release via intermolecular autophosphorylation; sub-aspect of core gradient-formation function. Supporting Evidence: PMID:26150232 auto-phosphorylates intermolecularly. |
| GO:0004674 protein serine/threonine kinase activity | IDA PMID:24508166 Dueling kinases regulate cell size at division through the S... | ACCEPT | Summary: IDA Ser/Thr kinase activity; Pom1 phosphorylates the C-terminal domain of Cdr2 to reduce its activating phosphorylation by Ssp1. Core MF. Reason: Direct phosphorylation of Cdr2 demonstrates Ser/Thr kinase activity. Supporting Evidence: PMID:24508166 prevent activation of Cdr2 kinase activity by the CaMKK Ssp1. |
| GO:0010972 negative regulation of G2/M transition of mitotic cell cycle | IMP PMID:24508166 Dueling kinases regulate cell size at division through the S... | ACCEPT | Summary: IMP annotation. Pom1 negatively regulates mitotic entry by phosphorylating Cdr2 to prevent its activation by Ssp1, opposing the Cdr2/Cdr1 -> Wee1 pathway. Core process. Reason: Pom1 delays G2/M by inhibiting Cdr2 activation. Supporting Evidence: PMID:24508166 prevent activation of Cdr2 kinase activity by the CaMKK Ssp1. |
| GO:0032153 cell division site | IDA PMID:12206652 Mac1, a fission yeast transmembrane protein localizing to th... | ACCEPT | Summary: IDA cell division site localization (study of the Mac1 transmembrane protein at poles and septum, with Pom1 as a co-localization marker). Core location, consistent with Pom1's role at the division site. Reason: Cell division site localization is consistent with Pom1's role in division plane positioning. Supporting Evidence: PMID:12206652 poles and septum, is required for correct cell separation at high temperatures. |
| GO:0051286 cell tip | IDA PMID:12206652 Mac1, a fission yeast transmembrane protein localizing to th... | ACCEPT | Summary: IDA cell tip localization. Redundant with other cell tip annotations; core location. Reason: Cell tip localization repeatedly demonstrated for Pom1. Supporting Evidence: PMID:12206652 poles and septum, is required for correct cell separation at high temperatures. |
| GO:0004674 protein serine/threonine kinase activity | IDA PMID:24316795 Distinct levels in Pom1 gradients limit Cdr2 activity and lo... | ACCEPT | Summary: IDA Ser/Thr kinase activity; Pom1 inhibits Cdr2 for mitotic commitment (distinct gradient thresholds set timing vs positioning). Core MF. Reason: Pom1 kinase activity inhibits Cdr2 for mitotic commitment. Supporting Evidence: PMID:24316795 Pom1 inhibits Cdr2 for mitotic commitment independently of regulating its localization or cortical levels. |
| GO:0031569 mitotic G2 cell size control checkpoint signaling | IGI PMID:24316795 Distinct levels in Pom1 gradients limit Cdr2 activity and lo... | ACCEPT | Summary: IGI annotation. Distinct levels in the Pom1 gradient limit Cdr2 activity and localization to time and position division, integrating cell size with mitotic commitment. Core process. Reason: Pom1 gradient thresholds couple cell size to mitotic commitment via Cdr2. Supporting Evidence: PMID:24316795 Pom1 inhibits Cdr2 for mitotic commitment independently of regulating its localization or cortical levels. |
| GO:0032153 cell division site | IDA PMID:22174761 Roles of the DYRK kinase Pom2 in cytokinesis, mitochondrial ... | ACCEPT | Summary: IDA cell division site localization (Pom2/Pom1 cytokinesis study). Core location. Reason: Consistent with Pom1's localization to and function at the division site. Supporting Evidence: PMID:22174761 Pom1, although they share 55% identity in the kinase domain and the Pom2 kinase domain functionally complements that of Pom1. |
| GO:0051286 cell tip | IDA PMID:22174761 Roles of the DYRK kinase Pom2 in cytokinesis, mitochondrial ... | ACCEPT | Summary: IDA cell tip localization (Pom2/Pom1 study). Redundant with other cell tip annotations; core location. Reason: Cell tip localization repeatedly demonstrated for Pom1. Supporting Evidence: PMID:22174761 Pom1, although they share 55% identity in the kinase domain and the Pom2 kinase domain functionally complements that of Pom1. |
| GO:1903617 positive regulation of mitotic cytokinesis, division site positioning | IMP PMID:9852154 Role of polo kinase and Mid1p in determining the site of cel... | ACCEPT | Summary: IMP annotation. Pom1 is required for proper placement of the Mid1p ring, contributing to correct positioning of the division site (acting in a pathway distinct from Plo1/Mid1). Core process. Reason: Pom1 contributes to correct division-site positioning via Mid1. Supporting Evidence: PMID:9852154 Pom1p is required for proper placement of the Mid1p ring. |
| GO:0051286 cell tip | IDA PMID:9573052 Pom1p, a fission yeast protein kinase that provides position... | ACCEPT | Summary: IDA cell tip localization from the founding Pom1 characterization. Pom1 provides positional information from the cell tips for growth and division. Core location. Reason: Cell tip localization established in the original Pom1 study. Supporting Evidence: PMID:9573052 provides positional information for both polarized growth and cytokinesis. |
| GO:0051286 cell tip | IDA PMID:20870879 Reorganization of the growth pattern of Schizosaccharomyces ... | ACCEPT | Summary: IDA cell tip localization observed during invasive filament formation; Pom1 is relatively depleted at the growing end and enriched at the nongrowing end under these conditions. Consistent with tip localization; core location. Reason: Cell tip/end localization observed; consistent with Pom1's tip-marker role. Supporting Evidence: PMID:20870879 Pom1, all show the opposite effect and are relatively depleted at the growing end and enriched at the nongrowing end, although Tea1 appears to continue to be delivered to both ends. |
| GO:0004674 protein serine/threonine kinase activity | IDA PMID:11230130 Fission yeast Pom1p kinase activity is cell cycle regulated ... | ACCEPT | Summary: IDA Ser/Thr kinase activity; Pom1 kinase activity is cell-cycle regulated and required for cellular symmetry. Core MF. Reason: Direct demonstration that Pom1 kinase activity is essential for symmetric growth and division. Supporting Evidence: PMID:11230130 Pom1p kinase activity is cell cycle regulated and essential for cellular symmetry during growth and division. |
| GO:0030427 site of polarized growth | IDA PMID:11230130 Fission yeast Pom1p kinase activity is cell cycle regulated ... | ACCEPT | Summary: IDA localization to the site of polarized growth (growing cell ends), where Pom1 promotes proper polarity. Core location, related to cell tip. Reason: Pom1 localizes to growing cell ends / sites of polarized growth. Supporting Evidence: PMID:11230130 Pom1p is present in a large protein complex and requires its non-catalytic domain to localize to the cell periphery and its kinase activity to localize to cell ends. |
| GO:0051285 cell cortex of cell tip | IDA PMID:11230130 Fission yeast Pom1p kinase activity is cell cycle regulated ... | ACCEPT | Summary: IDA cortex-of-cell-tip localization; Pom1 requires its non-catalytic domain to localize to the cell periphery and its kinase activity to localize to cell ends. Most specific accurate CC term. Core location. Reason: Directly observed tip cortical localization. Supporting Evidence: PMID:11230130 Pom1p is present in a large protein complex and requires its non-catalytic domain to localize to the cell periphery and its kinase activity to localize to cell ends. |
| GO:0051518 positive regulation of bipolar cell growth | IMP PMID:9573052 Pom1p, a fission yeast protein kinase that provides position... | ACCEPT | Summary: IMP annotation from the founding study. pom1 mutants mostly fail to switch to bipolar growth (NETO), growing only at the randomly chosen end. Pom1 positively regulates the activation of bipolar growth. Core process. Reason: Pom1 is required for the switch to bipolar growth. Supporting Evidence: PMID:9573052 most cells never switch to bipolar growth but instead grow exclusively at the randomly chosen end. |
| GO:0004674 protein serine/threonine kinase activity | IBA GO_REF:0000033 | ACCEPT | Summary: IBA transfer of the conserved protein serine/threonine kinase activity from PAINT node PTN000624408. Pom1 has extensive target-specific experimental evidence for this same catalytic activity. Reason: Protein serine/threonine kinase activity is conserved across the DYRK-family catalytic branch represented by PTN000624408, and Pom1 directly phosphorylates multiple serine/threonine substrates in vitro. Pom1's presence among the node's descendant evidence is expected experimental grounding, not circular support. Propagation Review Root cause: NO FAILURE CORE Sources checked: PANTHER:PTN000624408 SUPPORTS TRANSFER PAINT places the conserved serine/threonine kinase activity at this DYRK-family node, with direct experimental descendants including Pom1 itself. Supporting Evidence: PMID:25720772 Purified Pom1 phosphorylated these cell polarity targets in vitro, confirming that they are direct substrates of Pom1 kinase activity and likely contribute to regulation of polarized growth by Pom1. |
Loading supporting content…
Download this section (compressed HTML)Q: Given that pom1-deleted cells retain near-normal cell-size homeostasis, what is the precise contribution of the Pom1 gradient versus Cdr2-intrinsic and other size-sensing mechanisms to the timing of mitotic entry?
Q: What is the full physiological substrate repertoire of Pom1 beyond Cdr2, Cdc15, Rga4, Tea4, Mod5, Pal1, Rga7 and Syt22, and which substrates mediate each distinct output (size control vs division-plane positioning vs bipolar growth)?
Q: How is the tyrosine-autophosphorylation activity of Pom1 mechanistically coupled to its serine/threonine activity toward substrates, and does Tyr autophosphorylation regulate substrate selection or gradient dynamics?
Experiment: Use analog-sensitive (as) Pom1 alleles combined with rapid chemical inhibition and time-resolved phosphoproteomics to define direct Pom1 substrates and the temporal order of phosphorylation events during the cell cycle.
Experiment: Reconstitute the Pom1 membrane-binding/autophosphorylation cycle in vitro on supported lipid bilayers with defined phosphoinositide composition to dissect how lipid binding, intermolecular autophosphorylation, and Dis2 dephosphorylation jointly shape the gradient.
Experiment: Generate separation-of-function Pom1 mutants (e.g. selectively impairing Cdr2 phosphorylation, Cdc15 phosphorylation, or Rga4 regulation) to test whether the size-control, division-positioning, and bipolar-growth outputs can be genetically uncoupled.
Loading supporting content…
Download this section (compressed HTML)Loading supporting content…
Download this section (compressed HTML)