Serine/threonine-protein kinase involved in the spatial and temporal control system organizing cortical activities in mitotic and postmitotic cells. ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Down-regulated by Pseudomonas aeruginosa, PAO1 strain and up-regulated by PA14 strain infection. Prominent defect in cytokinesis and an impairment of multicellular development. In multinucleate sepA-null cells nuclear division proceed normally and synchronously. However, often cleavage furrows are either missing or atypical; they are extremely asymmetric and constriction is impaired. Null cells form fruiting bodies, but these are smaller than the wild-type ones. Belongs to the protein kinase superfamily. Ser/Thr protein kinase family.