Acts as a mitotic inducer. In G2 it negatively regulates wee1, a mitotic inhibitor. Also has a role in cytokinesis where it required for proper septum formation. ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Interacts with blt1 and mid1. Autophosphorylated. Belongs to the protein kinase superfamily. CAMK Ser/Thr protein kinase family. NIM1 subfamily.