Oocyte-specific protein tyrosine kinase that phosphorylates and inhibits cdk1 and acts as a key regulator of meiosis. Required to maintain meiotic arrest in oocytes by phosphorylating cdk1 at 'Tyr-15', which inhibits cdk1 activity and prevents meiotic reentry. Negative regulator of mitosis. Involved in the mitotic DNA replication checkpoint. ATP + L-tyrosyl-[protein] = ADP + H(+) + O-phospho-L-tyrosyl-[protein] Interacts with prmt5; this promotes protesomal degradation of wee2-a in the nucleus. The interaction with prmt5 is disrupted upon activation of the DNA replication checkpoint. Detected in egg (at protein level). Oocyte-specific maternally supplied protein. Present in immature and mature oocytes and in early (pregastrula) embryos, but not in post-gastrula embryos. Expressed only after meiosis I. Not detected in full-grown stage VI immature oocytes (arrested at prophase I) and in oocytes undergoing germinal vesicle breakdown (GVBD) or meiosis I, while it is present in oocytes from 1-1.5 hour after GVBD, or from the onset of meiosis II. Subject to proteasomal degradation in the nucleus. Belongs to the protein kinase superfamily. Ser/Thr protein kinase family. WEE1 subfamily. Was initially assigned as wee1 (PubMed:7749193). However, it corresponds to the meiosis-specific protein WEE2 in mammals.