Phospho-CDK1(Y15) Recombinant Rabbit mAb (S-M0020)

Phospho-CDK1(Y15) refers to cyclin-dependent kinase 1 (CDK1) that has undergone phosphorylation at the tyrosine 15 (Tyr15) residue, a critical post-translational modification regulating the G2/M checkpoint of the cell cycle and the initiation of mitosis. During the G2 phase, the kinases Wee1 and Myt1 phosphorylate CDK1 at Thr14 and Tyr15, inhibiting the kinase activity of the complex formed with Cyclin B, thereby blocking mitotic entry to ensure that damaged or incompletely replicated DNA is repaired. When the cell is poised to enter mitosis, the Cdc25 phosphatases (particularly Cdc25C) are activated and remove these inhibitory phosphoryl groups from Tyr15 and Thr14 through dephosphorylation, rapidly activating CDK1 kinase activity. This activation, in turn, phosphorylates downstream substrates (such as lamins and microtubule-associated proteins) to drive nuclear envelope breakdown, chromosome condensation, and spindle formation. The level of Phospho-CDK1(Y15) therefore serves as an important marker of cell cycle surveillance: its high expression indicates cell cycle arrest at the G2 phase or checkpoint capture following DNA damage, whereas its rapid decline prior to mitosis is a prerequisite for cell entry into the M phase. Aberrant regulation of Wee1 or Cdc25C in tumor cells often leads to altered Phospho-CDK1(Y15) signaling, directly affecting sensitivity to DNA-damaging chemotherapeutic agents (such as doxorubicin and cisplatin).