Serine/threonine-protein kinase that plays an essential role in the regulation of actin filament dynamics. Acts downstream of several Rho family GTPase signal transduction pathways. Involved in astral microtubule organization and mitotic spindle orientation during early stages of mitosis by mediating phosphorylation of TPPP. ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Binds ROCK1 and LKAP. Expressed predominantly in the lung, and faintly in the kidney, liver, brain, spleen, gizzard, and intestine. Belongs to the protein kinase superfamily. TKL Ser/Thr protein kinase family.