Kinase that phosphorylates MYL2 in vitro (By similarity). Has been proposed to be calmodulin-dependent, although MYL2 phosphorylation has also been observed in the presence or absence of calmodulin (By similarity). Promotes sarcomere formation in cardiomyocytes and increases cardiomyocyte contractility (By similarity). . This is the function of ENSG00000140795 (MYLK3, myosin light chain kinase 3).