Protein kinase which regulates actin filament dynamics. Phosphorylates and inactivates the actin binding/depolymerizing factor tsr/cofilin, thereby stabilizing the actin cytoskeleton. Modulation of actin cytoskeleton dynamics may be essential for imaginal disk morphogenesis and axon guidance. ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Interacts with LATS1, and this interaction inhibits phosphorylation of tsr/cofilin. Localizes to the cleavage furrow and the midbody at cytokinesis. Expressed throughout the imaginal disks of the eye, leg and wing. Expressed from early third instar to late pupal stages. Phosphorylated on serine and/or threonine residues by ROCK1. Phosphorylated by PAK4 resulting in increased LIMK1 ability to phosphorylate cofilin. May be dephosphorylated and inactivated by SSH1 (By similarity). Belongs to the protein kinase superfamily. TKL Ser/Thr protein kinase family.