Plays multiple roles in cell cycle progression, cytokinesis and apoptosis. Involved in pre-mRNA splicing in a kinase activity-dependent manner. May act as a negative regulator of normal cell cycle progression. ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Phosphorylation at Thr-437 or Tyr-438 inactivates the enzyme, while phosphorylation at Thr-584 activates it. May interact PAK1 and RANBP9. p110C interacts with RNPS1. Interacts with CCND3. Interacts with CCNL1 and CCNL2. Forms complexes with pre-mRNA-splicing factors, including at least SRSF1, SRSF2 AND SRSF7/SLU7. Phosphorylation at Ser-115 creates a binding site for 14-3-3 proteins. Belongs to the protein kinase superfamily. CMGC Ser/Thr protein kinase family. CDC2/CDKX subfamily.