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. Displays serine/threonine-specific phosphorylation of myelin basic protein and histone (MBP) in vitro. Suppresses ciliogenesis via multiple pathways; phosphorylation of CFL1, suppression of directional trafficking of ciliary vesicles to the ciliary base, and by facilitating YAP1 nuclear localization where it acts as a transcriptional corepressor of the TEAD4 target genes AURKA and PLK1 (By similarity). 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 MARF1 (By similarity). Interacts with NISCH (By similarity). Phosphorylated on serine and/or threonine residues by ROCK1. Belongs to the protein kinase superfamily. TKL Ser/Thr protein kinase family.