title: The role of 14-3-3ε interaction with phosphorylated Cdc25B at its Ser321 in the release of the mouse oocyte from prophase I arrest.
abstract: The protein kinase A (PKA)/Cdc25B pathway plays a critical role in maintaining meiotic arrest in mouse oocytes. However, the molecular mechanism underlying this interchange is not known. In this study, we assessed the role of 14-3-3ε interaction with phosphorylated Cdc25B at its Ser321 as the mouse oocyte is released from prophase I arrest. The 14-3-3ε isoform is a highly conserved protein with various regulatory roles, including maintenance of meiotic arrest. Cdc25B phosphatase is also a key cell cycle regulator. 14-3-3ε binds to Cdc25B-WT, which was abrogated when Ser321 of Cdc25B was mutated to Ala. In addition, we found that 14-3-3ε and Cdc25B were co-localized. Cdc25B was translocated from the cytoplasm to the nucleus shortly before germinal vesicle breakdown (GVBD) during the primary oocyte stage of oogenesis. However, mutation of Ser321 to Ala completely abolished the cytoplasmic localization of Cdc25B. Furthermore, oocytes co-expressing of Cdc25B-WT or Cdc25B-Ser321D and 14-3-3ε were unable to undergo GVBD. In contrast, co-expression of 14-3-3ε and Cdc25B-Ser321A induced GVBD and allowed the process to continue. Down-regulation of 14-3-3ε caused partial meiotic resumption. Taken together, these data indicate that Ser321 of Cdc25B is the specific binding site for 14-3-3ε binding, and that 14-3-3ε is the significant factor in Cdc25B regulation during meiotic resumption of GV stage.
authors: Department of Biochemical and Molecular Biology, China Medical University, Shenyang, Liaoning Province, China.
authors: Jun
authors: J
authors: Meng
authors: Cheng
authors: C
authors: Cui
authors: Yanchun
authors: Y
authors: Liu
authors: Minglin
authors: M
authors: Jin
authors: Didi
authors: D
authors: Wu
authors: Chao
authors: C
authors: Liu
authors: Enhua
authors: E
authors: Wang
authors: Bingzhi
authors: B
authors: Yu
mesh_terms: D048948:14-3-3 Proteins / Q000378:metabolism*; D000818:Animals; D001665:Binding Sites; D059447:Cell Cycle Checkpoints; D015536:Down-Regulation; D005260:Female; D055785:Gene Knockdown Techniques; D049469:Meiotic Prophase I; D051379:Mice; D009865:Oocytes / Q000166:cytology* / Q000201:enzymology*; D010766:Phosphorylation; D010768:Phosphoserine / Q000378:metabolism*; D011485:Protein Binding; D020033:Protein Isoforms / Q000378:metabolism; D021381:Protein Transport; D034741:RNA, Small Interfering / Q000378:metabolism; D020687:cdc25 Phosphatases / Q000378:metabolism*
chemical_list: D048948:14-3-3 Proteins; D020033:Protein Isoforms; D034741:RNA, Small Interfering; C576823:Ywhae protein, mouse; D010768:Phosphoserine; C517006:Cdc25b protein, mouse; D020687:cdc25 Phosphatases