MASTL

Existing Annotations Review

GO Term	Evidence	Action	Reason
GO:0000086 G2/M transition of mitotic cell cycle	IMP PMID:20538976 Loss of human Greatwall results in G2 arrest and multiple mi...	ACCEPT	Summary: MASTL promotes mitotic entry by inhibiting PP2A-B55 through phospho-ENSA/ARPP19; complete siRNA depletion arrests human cells in G2. Reason: This is the central, best-supported function of the gene. Human RNAi shows G2 arrest on full depletion and mitotic collapse on partial depletion, both rescued by PP2A co-depletion or okadaic acid, and the biochemical mechanism (phosphorylation of ENSA/ARPP19 to make them PP2A-B55 inhibitors) is established in Xenopus and reconstituted with human proteins. Supporting Evidence: PMID:20538976 This kinase promotes mitotic entry and maintenance in human cells by inhibiting protein phosphatase 2A (PP2A), a phosphatase that dephosphorylates cyclin B-Cdc2 substrates. The complete depletion of Gwl by siRNA arrests human cells in G2. PMID:20538976 These phenotypes appear to be mediated by PP2A, as they could be rescued by either a double Gwl/PP2A knockdown or by the inhibition of this phosphatase with okadaic acid. PMID:21164014 We identified cyclic adenosine monophosphate-regulated phosphoprotein 19 (Arpp19) and α-Endosulfine as two substrates of Gwl that, when phosphorylated by this kinase, associate with and inhibit PP2A, thus promoting mitotic entry.
GO:0000086 G2/M transition of mitotic cell cycle	IMP PMID:20818157 MASTL is the human orthologue of Greatwall kinase that facil...	ACCEPT	Summary: MASTL-depleted human cells delay in G2 and condense chromosomes slowly; MASTL sustains cyclin B1-CDK1-dependent mitotic phosphorylation. Reason: Independent human RNAi study reaching the same conclusion as PMID:20538976; the G2 delay and slow chromosome condensation are direct readouts of a defective G2/M transition. Supporting Evidence: PMID:20818157 Cells strongly depleted of MASTL by RNAi delay in G(2) phase and reveal slow chromosome condensation. PMID:20818157 our experiments indicate that MASTL supports the phosphorylation state of mitotic phospho-proteins downstream of cyclin B1-Cdk1, including the APC/C.
GO:0004672 protein kinase activity	IEA GO_REF:0000002	ACCEPT	Summary: Generic InterPro-derived protein kinase activity; correct but less specific than the experimentally established serine/threonine (serine) kinase activity. Reason: The mapping is correct and is a parent of the experimentally supported GO:0004674. An IEA at this level of specificity is acceptable. Supporting Evidence: PMID:38123684 This inhibition results in the full activation of mitotic kinases, including MASTL, which phosphorylates ARPP19 on Ser62 (pS62-ARPP19). PMID:21164013 We report that inhibition of PP2A-B55δ results from a small protein, known as α-endosulfine (Ensa), that is phosphorylated in mitosis by the protein kinase Greatwall (Gwl). This converts Ensa into a potent and specific inhibitor of PP2A-B55δ.
GO:0004674 protein serine/threonine kinase activity	IBA GO_REF:0000033	ACCEPT	Summary: PAINT propagation of serine/threonine kinase activity from the deep AGC-kinase node (PTN000683254); MASTL's own IDA is among the descendant evidence. Reason: The phylogenetic placement at the AGC family node is sound, MASTL is inside that clade, and the activity is directly demonstrated for MASTL on ENSA Ser67 and ARPP19 Ser62. The target appearing in its own WITH/FROM is expected and marks experimental grounding on the target itself. Supporting Evidence: PMID:38123684 This inhibition results in the full activation of mitotic kinases, including MASTL, which phosphorylates ARPP19 on Ser62 (pS62-ARPP19). PMID:21164013 We report that inhibition of PP2A-B55δ results from a small protein, known as α-endosulfine (Ensa), that is phosphorylated in mitosis by the protein kinase Greatwall (Gwl). This converts Ensa into a potent and specific inhibitor of PP2A-B55δ.
GO:0004674 protein serine/threonine kinase activity	IDA PMID:20538976 Loss of human Greatwall results in G2 arrest and multiple mi...	ACCEPT	Summary: Human Greatwall (MAST-L) kinase activity assayed directly; the cached abstract-only record names the kinase and its PP2A-directed function. Reason: Core catalytic activity of the gene; the kinase assays in the full text are consistent with the later identification of ENSA/ARPP19 as substrates and with Reactome's human reactions. Supporting Evidence: PMID:20538976 This kinase promotes mitotic entry and maintenance in human cells by inhibiting protein phosphatase 2A (PP2A), a phosphatase that dephosphorylates cyclin B-Cdc2 substrates. The complete depletion of Gwl by siRNA arrests human cells in G2. PMID:38123684 This inhibition results in the full activation of mitotic kinases, including MASTL, which phosphorylates ARPP19 on Ser62 (pS62-ARPP19).
GO:0004674 protein serine/threonine kinase activity	IEA GO_REF:0000120	ACCEPT	Summary: Combined automated assignment from the AGC C-terminal domain, the MASTL-specific kinase domain signature and EC 2.7.11.1. Reason: Consistent with the experimentally demonstrated activity. Supporting Evidence: PMID:38123684 This inhibition results in the full activation of mitotic kinases, including MASTL, which phosphorylates ARPP19 on Ser62 (pS62-ARPP19). PMID:21164013 We report that inhibition of PP2A-B55δ results from a small protein, known as α-endosulfine (Ensa), that is phosphorylated in mitosis by the protein kinase Greatwall (Gwl). This converts Ensa into a potent and specific inhibitor of PP2A-B55δ.
GO:0004674 protein serine/threonine kinase activity	TAS Reactome:R-HSA-2168079	ACCEPT	Summary: Reactome reaction in which MASTL phosphorylates ARPP19 on Ser62. Reason: Correct and specific description of the core reaction of the gene. Supporting Evidence: Reactome:R-HSA-2168079 MASTL (GWL i.e. Greatwall kinase) phosphorylates ARPP19 on serine residue S62 (Gharbi-Ayachi et al. 2010). PMID:38123684 This inhibition results in the full activation of mitotic kinases, including MASTL, which phosphorylates ARPP19 on Ser62 (pS62-ARPP19).
GO:0004674 protein serine/threonine kinase activity	TAS Reactome:R-HSA-2430535	ACCEPT	Summary: Reactome reaction in which MASTL phosphorylates ENSA on Ser67. Reason: Correct and specific description of the core reaction of the gene. Supporting Evidence: Reactome:R-HSA-2430535 MASTL (GWL) activates ENSA by phosphorylating it on serine residue S67 (Mochida et al. 2010, Gharbi-Ayachi et al. 2010). PMID:21164013 We report that inhibition of PP2A-B55δ results from a small protein, known as α-endosulfine (Ensa), that is phosphorylated in mitosis by the protein kinase Greatwall (Gwl). This converts Ensa into a potent and specific inhibitor of PP2A-B55δ.
GO:0005524 ATP binding	IEA GO_REF:0000002	ACCEPT	Summary: ATP binding implied by the protein kinase domain; Lys72 mutation abolishes activity and a minimal domain construct shows ATP-dependent catalysis. Reason: Standard cofactor/substrate annotation for an active protein kinase, consistent with the UniProt ATP-binding features and the demonstrated catalytic activity. Supporting Evidence: file:human/MASTL/MASTL-uniprot.txt BINDING 41..49 /ligand="ATP"
GO:0005634 nucleus	EXP PMID:19460416 In vivo inactivation of MASTL kinase results in thrombocytop...	ACCEPT	Summary: RFP-tagged wild-type and E167D MASTL localize to the nucleus of transfected cells. Reason: Direct imaging of the human protein; consistent with the interphase nuclear localization reported by the two 2010 human studies and with UniProt. Supporting Evidence: PMID:19460416 The MASTL kinase protein, both wildtype and mutant forms, appears to localize within the nucleus of these BHK cells (Figure 6, Panels A & B) as determined by co-localization with the DNA counterstain, TO-PRO-3.
GO:0005634 nucleus	IBA GO_REF:0000033	ACCEPT	Summary: PAINT propagation of nuclear localization within the Greatwall subfamily, seeded by Drosophila gwl, zebrafish, pig and human MASTL. Reason: Greatwall kinases are nuclear in interphase across metazoa; the human protein is among the experimental sources, and activation begins in the nucleus before nuclear envelope breakdown. Supporting Evidence: PMID:20818157 We found that MASTL localizes to the nucleus in interphase and re-localizes in part to centrosomes in mitosis, when it is active. PMID:19460416 The MASTL kinase protein, both wildtype and mutant forms, appears to localize within the nucleus of these BHK cells (Figure 6, Panels A & B) as determined by co-localization with the DNA counterstain, TO-PRO-3.
GO:0005634 nucleus	IDA PMID:20538976 Loss of human Greatwall results in G2 arrest and multiple mi...	ACCEPT	Summary: Interphase nuclear localization of human Greatwall. Reason: Consistent with all other localization evidence (PMID:20818157, PMID:19460416, UniProt). Supporting Evidence: PMID:20818157 We found that MASTL localizes to the nucleus in interphase and re-localizes in part to centrosomes in mitosis, when it is active. PMID:19460416 The MASTL kinase protein, both wildtype and mutant forms, appears to localize within the nucleus of these BHK cells (Figure 6, Panels A & B) as determined by co-localization with the DNA counterstain, TO-PRO-3.
GO:0005634 nucleus	IDA PMID:20818157 MASTL is the human orthologue of Greatwall kinase that facil...	ACCEPT	Summary: MASTL is nuclear in interphase and partly centrosomal in mitosis. Reason: Directly stated in the abstract. Supporting Evidence: PMID:20818157 We found that MASTL localizes to the nucleus in interphase and re-localizes in part to centrosomes in mitosis, when it is active.
GO:0005634 nucleus	IEA GO_REF:0000044	ACCEPT	Summary: UniProt subcellular-location keyword mapping (Nucleus). Reason: Mirrors the experimental annotations. Supporting Evidence: PMID:20818157 We found that MASTL localizes to the nucleus in interphase and re-localizes in part to centrosomes in mitosis, when it is active. PMID:19460416 The MASTL kinase protein, both wildtype and mutant forms, appears to localize within the nucleus of these BHK cells (Figure 6, Panels A & B) as determined by co-localization with the DNA counterstain, TO-PRO-3.
GO:0005654 nucleoplasm	IDA GO_REF:0000052	ACCEPT	Summary: Human Protein Atlas immunofluorescence places MASTL in the nucleoplasm. Reason: Consistent with the interphase nuclear localization seen with tagged protein; the more specific sub-nuclear term is appropriate for a soluble kinase. Supporting Evidence: PMID:20818157 We found that MASTL localizes to the nucleus in interphase and re-localizes in part to centrosomes in mitosis, when it is active. PMID:19460416 The MASTL kinase protein, both wildtype and mutant forms, appears to localize within the nucleus of these BHK cells (Figure 6, Panels A & B) as determined by co-localization with the DNA counterstain, TO-PRO-3.
GO:0005654 nucleoplasm	TAS Reactome:R-HSA-2168079	ACCEPT	Summary: Reactome places the MASTL-ARPP19 phosphorylation reaction in the nucleoplasm. Reason: Consistent with interphase/prophase nuclear localization of MASTL; the same reaction also occurs in the cytoplasm after nuclear envelope breakdown, which Reactome does not model. Supporting Evidence: PMID:20818157 We found that MASTL localizes to the nucleus in interphase and re-localizes in part to centrosomes in mitosis, when it is active. PMID:19460416 The MASTL kinase protein, both wildtype and mutant forms, appears to localize within the nucleus of these BHK cells (Figure 6, Panels A & B) as determined by co-localization with the DNA counterstain, TO-PRO-3.
GO:0005654 nucleoplasm	TAS Reactome:R-HSA-2430535	ACCEPT	Summary: Reactome places the MASTL-ENSA phosphorylation reaction in the nucleoplasm. Reason: As for R-HSA-2168079. Supporting Evidence: PMID:20818157 We found that MASTL localizes to the nucleus in interphase and re-localizes in part to centrosomes in mitosis, when it is active. PMID:19460416 The MASTL kinase protein, both wildtype and mutant forms, appears to localize within the nucleus of these BHK cells (Figure 6, Panels A & B) as determined by co-localization with the DNA counterstain, TO-PRO-3.
GO:0005813 centrosome	IDA PMID:20538976 Loss of human Greatwall results in G2 arrest and multiple mi...	ACCEPT	Summary: Mitotic centrosomal localization of human Greatwall. Reason: The cached abstract does not describe localization, but the curator read the full text and the finding is independently reported for MASTL in mitosis (PMID:20818157) and recorded by UniProt. Supporting Evidence: PMID:20818157 We found that MASTL localizes to the nucleus in interphase and re-localizes in part to centrosomes in mitosis, when it is active. file:human/MASTL/MASTL-uniprot.txt During interphase is mainly nuclear, upon nuclear envelope breakdown localizes at the cytoplasm and during mitosis at the centrosomes.
GO:0005813 centrosome	IEA GO_REF:0000044	ACCEPT	Summary: UniProt subcellular-location keyword mapping (Centrosome). Reason: Mirrors the experimental annotation. Supporting Evidence: PMID:20818157 We found that MASTL localizes to the nucleus in interphase and re-localizes in part to centrosomes in mitosis, when it is active. file:human/MASTL/MASTL-uniprot.txt During interphase is mainly nuclear, upon nuclear envelope breakdown localizes at the cytoplasm and during mitosis at the centrosomes.
GO:0006974 DNA damage response	ISS GO_REF:0000024	KEEP AS NON CORE	Summary: Transferred from Xenopus Greatwall, which is inhibited by the DNA damage response and promotes checkpoint recovery (re-entry into mitosis after damage removal) in egg extracts. Reason: The Xenopus evidence is sound and the biology is plausible for human MASTL, but the role is an application of its core G2/M-promoting activity to the recovery phase of the checkpoint rather than a distinct DNA-damage function, and there is no direct human experimental annotation. Keep as a non-core, orthology-inferred process. Supporting Evidence: file:human/MASTL/MASTL-uniprot.txt Following DNA damage, it is also involved in checkpoint recovery by being inhibited.
GO:0007346 regulation of mitotic cell cycle	IBA GO_REF:0000033	ACCEPT	Summary: PAINT propagation across the Greatwall/Rim15/Ppk18 subfamily; all characterized members regulate the mitotic cell cycle through the endosulfine-PP2A-B55 axis. Reason: The node placement is sound and the human protein has direct IMP evidence for the more specific G2/M transition term; this parent term correctly summarizes the conserved function. Supporting Evidence: PMID:20538976 This kinase promotes mitotic entry and maintenance in human cells by inhibiting protein phosphatase 2A (PP2A), a phosphatase that dephosphorylates cyclin B-Cdc2 substrates. The complete depletion of Gwl by siRNA arrests human cells in G2. PMID:20538976 These phenotypes appear to be mediated by PP2A, as they could be rescued by either a double Gwl/PP2A knockdown or by the inhibition of this phosphatase with okadaic acid. PMID:21164014 We identified cyclic adenosine monophosphate-regulated phosphoprotein 19 (Arpp19) and α-Endosulfine as two substrates of Gwl that, when phosphorylated by this kinase, associate with and inhibit PP2A, thus promoting mitotic entry.
GO:0007346 regulation of mitotic cell cycle	TAS Reactome:R-HSA-2465910	ACCEPT	Summary: Reactome pathway 'MASTL Facilitates Mitotic Progression'. Reason: Accurate summary of the core function. Supporting Evidence: Reactome:R-HSA-2465910 Activated MASTL phosphorylates ARPP19 and ENSA on serines S62 and S67, respectively, enabling them to bind to and inhibit the phosphatase activity of PP2A complexed with the regulatory subunit PPP2R2D (B55-delta).
GO:0015630 microtubule cytoskeleton	IBA GO_REF:0000033	ACCEPT	Summary: PAINT propagation of microtubule-cytoskeleton localization, reflecting the mitotic centrosomal localization of vertebrate Greatwall. Reason: MASTL localizes to centrosomes in mitosis (a part of the microtubule cytoskeleton) and the human protein is among the experimental sources; the term is the appropriate generalization for the subfamily node. Supporting Evidence: PMID:20818157 We found that MASTL localizes to the nucleus in interphase and re-localizes in part to centrosomes in mitosis, when it is active. file:human/MASTL/MASTL-uniprot.txt During interphase is mainly nuclear, upon nuclear envelope breakdown localizes at the cytoplasm and during mitosis at the centrosomes.
GO:0016301 kinase activity	IDA PMID:20818157 MASTL is the human orthologue of Greatwall kinase that facil...	MODIFY	Summary: Kinase activity of MASTL is demonstrated, but the generic term is less informative than the established protein serine/threonine kinase activity. Reason: The activity is real; the cited study shows active MASTL in mitosis, and its substrates ENSA Ser67 and ARPP19 Ser62 are serine residues in proteins. Use the specific protein serine/threonine kinase term already carried by the gene. Proposed replacements: protein serine/threonine kinase activity Supporting Evidence: PMID:20818157 We found that MASTL localizes to the nucleus in interphase and re-localizes in part to centrosomes in mitosis, when it is active. PMID:38123684 This inhibition results in the full activation of mitotic kinases, including MASTL, which phosphorylates ARPP19 on Ser62 (pS62-ARPP19).
GO:0032154 cleavage furrow	IDA PMID:20538976 Loss of human Greatwall results in G2 arrest and multiple mi...	ACCEPT	Summary: Human Greatwall localizes to the cleavage furrow at mitotic exit. Reason: The cached abstract is silent on this, but the same localization is recorded by UniProt from PMID:20818157 and is consistent with the cytokinesis defects seen after depletion. Supporting Evidence: file:human/MASTL/MASTL-uniprot.txt Upon mitotic exit moves to the cleavage furrow. PMID:20818157 MASTL RNAi cells that enter and progress through mitosis often fail to completely separate their sister chromatids in anaphase. This causes chromatin to be trapped in the cleavage furrow, which may lead to the formation of 4N G(1) cells by cytokinesis failure.
GO:0032154 cleavage furrow	IDA PMID:20818157 MASTL is the human orthologue of Greatwall kinase that facil...	ACCEPT	Summary: MASTL relocalizes to the cleavage furrow at mitotic exit. Reason: Source of the UniProt subcellular-location statement; consistent with the cytokinesis phenotype of depleted cells. Supporting Evidence: file:human/MASTL/MASTL-uniprot.txt Upon mitotic exit moves to the cleavage furrow. PMID:20818157 MASTL RNAi cells that enter and progress through mitosis often fail to completely separate their sister chromatids in anaphase. This causes chromatin to be trapped in the cleavage furrow, which may lead to the formation of 4N G(1) cells by cytokinesis failure.
GO:0032154 cleavage furrow	IEA GO_REF:0000044	ACCEPT	Summary: UniProt subcellular-location keyword mapping (Cleavage furrow). Reason: Mirrors the experimental annotation. Supporting Evidence: file:human/MASTL/MASTL-uniprot.txt Upon mitotic exit moves to the cleavage furrow. PMID:20818157 MASTL RNAi cells that enter and progress through mitosis often fail to completely separate their sister chromatids in anaphase. This causes chromatin to be trapped in the cleavage furrow, which may lead to the formation of 4N G(1) cells by cytokinesis failure.
GO:0035556 intracellular signal transduction	IBA GO_REF:0000033	KEEP AS NON CORE	Summary: PAINT propagation of a generic signalling term from the deep AGC-kinase node (PTN000683254), the same node as the serine/threonine kinase IBA. Reason: MASTL does relay a signal inside the cell (cyclin B-CDK1 activates MASTL, which phosphorylates ENSA/ARPP19 to switch off PP2A-B55), so the term is not wrong and the node placement is defensible for the AGC family. It adds nothing beyond the mitotic cell-cycle terms, so it is retained as a non-core, generic parent rather than as a core function. Supporting Evidence: PMID:20538976 This kinase promotes mitotic entry and maintenance in human cells by inhibiting protein phosphatase 2A (PP2A), a phosphatase that dephosphorylates cyclin B-Cdc2 substrates. The complete depletion of Gwl by siRNA arrests human cells in G2. PMID:20538976 These phenotypes appear to be mediated by PP2A, as they could be rescued by either a double Gwl/PP2A knockdown or by the inhibition of this phosphatase with okadaic acid. PMID:21164014 We identified cyclic adenosine monophosphate-regulated phosphoprotein 19 (Arpp19) and α-Endosulfine as two substrates of Gwl that, when phosphorylated by this kinase, associate with and inhibit PP2A, thus promoting mitotic entry.
GO:0044325 transmembrane transporter binding	IEA GO_REF:0000107	REMOVE	Summary: Ensembl Compara projection of a mouse Mastl IPI (binding to the K-Cl cotransporter Slc12a6/KCC3) whose source publication has been retracted. Reason: The only support is an electronic transfer of a mouse interaction annotation (PMID:27782176, a kinome screen for cation-chloride cotransporter regulators) that PubMed now lists as a retracted article. There is no human evidence that MASTL binds any transmembrane transporter, and the claim has no connection to the established endosulfine-PP2A biology. Removal does not assert that the mouse interaction was false, only that it is unsupported and uninformative for the human gene.
GO:0051721 protein phosphatase 2A binding	ISS GO_REF:0000024	MARK AS OVER ANNOTATED	Summary: Transferred from Xenopus Greatwall, which co-precipitates PP2A from egg extracts; the subsequent substrate work showed that Greatwall inhibits PP2A-B55 indirectly through phospho-ENSA/ARPP19 rather than by binding the phosphatase itself. Reason: A Gwl-PP2A association was reported in Xenopus extracts before the endosulfine mechanism was known, and it is most simply explained by the ternary Gwl-phospho-endosulfine-PP2A-B55 context. UniProt itself states that MASTL 'does not directly inhibit PP2A'. For human MASTL no direct binding has been demonstrated, and presenting PP2A binding as a molecular function of the kinase misrepresents the mechanism; the informative molecular function is the serine kinase activity toward ENSA/ARPP19. Supporting Evidence: file:human/MASTL/MASTL-uniprot.txt does not directly inhibit PP2A but acts by mediating phosphorylation and subsequent activation of ARPP19 and ENSA PMID:21164014 We identified cyclic adenosine monophosphate-regulated phosphoprotein 19 (Arpp19) and α-Endosulfine as two substrates of Gwl that, when phosphorylated by this kinase, associate with and inhibit PP2A, thus promoting mitotic entry.
GO:0051726 regulation of cell cycle	IMP PMID:20818157 MASTL is the human orthologue of Greatwall kinase that facil...	MODIFY	Summary: MASTL depletion causes G2 delay, incomplete anaphase and cytokinesis failure; the phenotype is specifically a mitotic cell-cycle defect. Reason: The evidence is sound but the term is broader than necessary. All the reported phenotypes (G2 delay, slow chromosome condensation, anaphase and cytokinesis failure, incomplete cyclin B1 destruction) concern the mitotic cell cycle, so the more specific regulation of mitotic cell cycle term (already carried by IBA and Reactome) should be used; the same paper also supports the G2/M transition annotation. Proposed replacements: regulation of mitotic cell cycle Supporting Evidence: PMID:20818157 Cells strongly depleted of MASTL by RNAi delay in G(2) phase and reveal slow chromosome condensation. PMID:20818157 MASTL RNAi cells that enter and progress through mitosis often fail to completely separate their sister chromatids in anaphase. This causes chromatin to be trapped in the cleavage furrow, which may lead to the formation of 4N G(1) cells by cytokinesis failure.
GO:0106310 protein serine kinase activity	IEA GO_REF:0000116	ACCEPT	Summary: Rhea-derived protein serine kinase activity; the physiological sites ENSA Ser67 and ARPP19 Ser62 are serines. Reason: Correct and, for the known substrates, the most precise catalytic term. Supporting Evidence: PMID:38123684 This inhibition results in the full activation of mitotic kinases, including MASTL, which phosphorylates ARPP19 on Ser62 (pS62-ARPP19). PMID:21164013 We report that inhibition of PP2A-B55δ results from a small protein, known as α-endosulfine (Ensa), that is phosphorylated in mitosis by the protein kinase Greatwall (Gwl). This converts Ensa into a potent and specific inhibitor of PP2A-B55δ.
GO:0005737 cytoplasm	IDA PMID:20818157 MASTL is the human orthologue of Greatwall kinase that facil...	NEW	Summary: Proposed cellular-component annotation. After nuclear envelope breakdown MASTL is dispersed through the mitotic cytoplasm, where it phosphorylates ENSA/ARPP19 to keep PP2A-B55 inhibited; the existing nucleus/centrosome/cleavage-furrow terms do not capture this compartment. Reason: UniProt records the cytoplasmic localization upon nuclear envelope breakdown from PMID:20818157, and the mitotic phosphorylation of the endosulfines and inhibition of PP2A-B55 necessarily take place in the cytoplasm once the nuclear envelope has broken down. This is a localization statement supported by curated data, not a new process claim. Supporting Evidence: file:human/MASTL/MASTL-uniprot.txt During interphase is mainly nuclear, upon nuclear envelope breakdown localizes at the cytoplasm and during mitosis at the centrosomes. file:human/MASTL/MASTL-deep-research-falcon.md The protein is predominantly nuclear in interphase and becomes dispersed after nuclear-envelope breakdown. PMID:20818157 We found that MASTL localizes to the nucleus in interphase and re-localizes in part to centrosomes in mitosis, when it is active.

Gene Description

Existing Annotations Review

Core Functions

Cyclin B-CDK1-activated protein serine kinase that phosphorylates the endosulfines ENSA (Ser67) and ARPP19 (Ser62), converting them into inhibitors of PP2A-B55 so that CDK1 substrate phosphorylation can accumulate and the cell commits to mitosis at the G2/M transition.

References

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