CDK11p58 Phosphorylation of PAK1 Ser174 Promotes DLC2 Binding and Roles on Cell Cycle Progression
CDK11p58, a CDK11 family Ser/Thr kinase, is a G2/M specific protein and contributed to regulation of cell cycle, transcription and apoptotic signal transduction. Recently, CDK11p58 has been reported to exert important functions in mitotic process, such as the regulation of bipolar spindle formation and sister chromatid cohesion. Here, we identified p21 activated kinase 1 (PAK1) as a new CDK11p58 substrate and we mapped a new phosphorylation site of Ser174 on PAK1. By mutagenesis, we created PAK1174A and PAK1174E, which mimic the dephosphorylated and phosphorylated form of PAK1; further analysis showed PAK1174E could be recruited to myosin V motor complex through binding to dynein light chain 2 (DLC2). PAK1174E could accelerate the mitosis progression in a nocodazole blocked cell model, while PAK1174A exhibited an opposite role. Our results indicated PAK1 may serve as a downstream effector of CDK11p58 during mitosis progression.