Which enzyme removes inhibitory phosphate from CDK1 to activate mitosis?
Release from Wee1-mediated inhibition is pivotal for mitotic entry, executed by Cdc25 family of dual specificity phosphatases capable of hydrolyzing phospho-threonine, phospho-serine and phospho-tyrosine. Three isoforms A, B, C exist in mammals, each with N-terminal regulatory domain containing 14-3-3 binding sites, nuclear export signals, Polo box binding motifs, and C-terminal catalytic domain bearing HCX5R active site with catalytic cysteine. During unperturbed cycle Cdc25B initiates activation at centrosomes early G2, followed by Cdc25C amplifying response. Polo-like kinase 1 phosphorylate
Ref: Nilsson & Hoffmann, Cdc25 Phosphatases Activate CDK1 for Mitosis, Cell Cycle 2000; Alberts et al., Chapter 17, Cdc25 Function.