{"type": "root", "children": [{"type": "p", "children": [{"type": "t", "text": "\nThe Wee1-like kinase discussed in these studies acts as a crucial negative regulator of cell cycle progression in oocytes and early embryos by phosphorylating CDK1 at an inhibitory site. In mouse oocytes, this kinase – operating downstream of protein kinase A (PKA) – is essential for maintaining meiotic arrest by keeping the maturation promoting factor (MPF) inactive until the appropriate hormonal signal triggers cell cycle reentry."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "1"}]}, {"type": "t", "text": "\n"}]}, {"type": "t", "text": "\n\n"}, {"type": "p", "children": [{"type": "t", "text": "\nIn addition to its role in establishing meiotic arrest, this kinase is required during egg activation to ensure a proper metaphase-to-anaphase transition. Calcium–calmodulin-dependent kinase II (CaMKII) activates the kinase, and its activity is critical for reducing Cdc2 activity. Disruption of this pathway prevents the formation of a pronucleus, indicating that both proteolytic degradation of cyclin B and inhibitory phosphorylation of Cdc2 are needed for successful cell cycle progression post-fertilization."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "2"}]}, {"type": "t", "text": "\n"}]}, {"type": "t", "text": "\n\n"}, {"type": "p", "children": [{"type": "t", "text": "\nMoreover, in one‐cell stage mouse embryos, regulation of the kinase through phosphorylation at Ser15 is pivotal during the G2/M transition. Phosphorylation by PKA and subsequent dephosphorylation dynamics modulate its activity, thereby directly impacting Cdc2 (CDK1) and ensuring that mitotic entry is properly timed. Overexpression studies of a phospho‐mimic mutant further underscore the importance of precise control of this kinase in driving cell cycle events in early embryogenesis."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "3"}]}, {"type": "t", "text": "\n"}]}, {"type": "rg", "children": [{"type": "r", "ref": 1, "children": [{"type": "t", "text": "Seung Jin Han, Ruby Chen, Maria Paola Paronetto, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Wee1B is an oocyte-specific kinase involved in the control of meiotic arrest in the mouse."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Curr Biol (2005)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1016/j.cub.2005.07.056"}], "href": "https://doi.org/10.1016/j.cub.2005.07.056"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "16169490"}], "href": "https://pubmed.ncbi.nlm.nih.gov/16169490"}]}, {"type": "r", "ref": 2, "children": [{"type": "t", "text": "Jeong Su Oh, Andrej Susor, Marco Conti "}, {"type": "b", "children": [{"type": "t", "text": "Protein tyrosine kinase Wee1B is essential for metaphase II exit in mouse oocytes."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Science (2011)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1126/science.1199211"}], "href": "https://doi.org/10.1126/science.1199211"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "21454751"}], "href": "https://pubmed.ncbi.nlm.nih.gov/21454751"}]}, {"type": "r", "ref": 3, "children": [{"type": "t", "text": "Chao Liu, Yanchun Liu, Yang Liu, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Ser 15 of WEE1B is a potential PKA phosphorylation target in G2/M transition in one-cell stage mouse embryos."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Mol Med Rep (2013)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.3892/mmr.2013.1437"}], "href": "https://doi.org/10.3892/mmr.2013.1437"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "23616086"}], "href": "https://pubmed.ncbi.nlm.nih.gov/23616086"}]}]}]}