title: Unique subcellular distribution of phosphorylated Plk1 (Ser137 and Thr210) in mouse oocytes during meiotic division and pPlk1(Ser137) involvement in spindle formation and REC8 cleavage.
abstract: Polo-like kinase 1 (Plk1) is pivotal for proper mitotic progression, its targeting activity is regulated by precise subcellular positioning and phosphorylation. Here we assessed the protein expression, subcellular localization and possible functions of phosphorylated Plk1 (pPlk1(Ser137) and pPlk1(Thr210)) in mouse oocytes during meiotic division. Western blot analysis revealed a peptide of pPlk1(Ser137) with high and stable expression from germinal vesicle (GV) until metaphase II (MII), while pPlk1(Thr210) was detected as one large single band at GV stage and 2 small bands after germinal vesicle breakdown (GVBD), which maintained stable up to MII. Immunofluorescence analysis showed pPlk1(Ser137) was colocalized with microtubule organizing center (MTOC) proteins, γ-tubulin and pericentrin, on spindle poles, concomitantly with persistent concentration at centromeres and dynamic aggregation between chromosome arms. Differently, pPlk1(Thr210) was persistently distributed across the whole body of chromosomes after meiotic resumption. The specific Plk1 inhibitor, BI2536, repressed pPlk1(Ser137) accumulation at MTOCs and between chromosome arms, consequently disturbed γ-tubulin and pericentrin recruiting to MTOCs, destroyed meiotic spindle formation, and delayed REC8 cleavage, therefore arresting oocytes at metaphase I (MI) with chromosome misalignment. BI2536 completely reversed the premature degradation of REC8 and precocious segregation of chromosomes induced with okadaic acid (OA), an inhibitor to protein phosphatase 2A. Additionally, the protein levels of pPlk1(Ser137) and pPlk1(Thr210), as well as the subcellular distribution of pPlk1(Thr210), were not affected by BI2536. Taken together, our results demonstrate that Plk1 activity is required for meiotic spindle assembly and REC8 cleavage, with pPlk1(Ser137) is the action executor, in mouse oocytes during meiotic division.
authors.affiliation: a Department of Histology and Embryology ; School of Basic Medical Sciences; Capital Medical University ; Beijing , China.
authors.forename: Juan
authors.initials: J
authors.lastname: Du
authors.affiliation: a Department of Histology and Embryology ; School of Basic Medical Sciences; Capital Medical University ; Beijing , China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Cao
authors.affiliation: a Department of Histology and Embryology ; School of Basic Medical Sciences; Capital Medical University ; Beijing , China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Wang
authors.affiliation: a Department of Histology and Embryology ; School of Basic Medical Sciences; Capital Medical University ; Beijing , China.
authors.forename: Nana
authors.initials: N
authors.lastname: Zhang
authors.affiliation: a Department of Histology and Embryology ; School of Basic Medical Sciences; Capital Medical University ; Beijing , China.
authors.forename: Xiaoyu
authors.initials: X
authors.lastname: Liu
authors.affiliation: a Department of Histology and Embryology ; School of Basic Medical Sciences; Capital Medical University ; Beijing , China.
authors.forename: Dandan
authors.initials: D
authors.lastname: Chen
authors.affiliation: a Department of Histology and Embryology ; School of Basic Medical Sciences; Capital Medical University ; Beijing , China.
authors.forename: Xiaoyun
authors.initials: X
authors.lastname: Liu
authors.affiliation: b Department of Neurobiology ; School of Basic Medical Sciences; Capital Medical University ; Beijing , China.
authors.forename: Qunyuan
authors.initials: Q
authors.lastname: Xu
authors.affiliation: a Department of Histology and Embryology ; School of Basic Medical Sciences; Capital Medical University ; Beijing , China.
authors.forename: Wei
authors.initials: W
authors.lastname: Ma
mesh_terms: D000818:Animals; D000941:Antigens / Q000235:genetics / Q000378:metabolism; D050256:Antimitotic Agents / Q000494:pharmacology; D018797:Cell Cycle Proteins / Q000235:genetics* / Q000378:metabolism; D020090:Chromosome Segregation; D054885:Cumulus Cells / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D048749:Cytokinesis / Q000235:genetics; D005260:Female; D018507:Gene Expression Regulation, Developmental; D008540:Meiosis; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D022101:Microtubule-Organizing Center / Q000378:metabolism / Q000648:ultrastructure; D009687:Nuclear Proteins / Q000235:genetics* / Q000378:metabolism; D019319:Okadaic Acid / Q000494:pharmacology; D009865:Oocytes / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D010750:Phosphoproteins / Q000235:genetics* / Q000378:metabolism; D010766:Phosphorylation; D054648:Protein Phosphatase 2 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000235:genetics* / Q000378:metabolism; D059748:Proteolysis; D011518:Proto-Oncogene Proteins / Q000235:genetics* / Q000378:metabolism; D011621:Pteridines / Q000494:pharmacology; D015398:Signal Transduction; D008941:Spindle Apparatus / Q000378:metabolism / Q000648:ultrastructure; D014404:Tubulin / Q000235:genetics / Q000378:metabolism; D000097869:Polo-Like Kinase 1
chemical_list: D000941:Antigens; D050256:Antimitotic Agents; D018797:Cell Cycle Proteins; D009687:Nuclear Proteins; D019319:Okadaic Acid; D010750:Phosphoproteins; D054648:Protein Phosphatase 2; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D011621:Pteridines; D014404:Tubulin; D000097869:Polo-Like Kinase 1; C518477:BI 2536; C465863:Rec8 protein, mouse; C086178:pericentrin
keywords: MTOC; Plk1 phosphorylation; REC8 cleavage; mouse; oocytes; spindle formation