Enables enzyme binding activity. Involved in tonic smooth muscle contraction. Acts upstream of or within cellular response to calcium ion; cellular response to potassium ion; and cellular response to xenobiotic stimulus. Located in cell-cell junction. Is expressed in several structures, including central nervous system; heart; liver; and retina. Human ortholog(s) of this gene implicated in adult respiratory distress syndrome; asthma; and thoracic aortic aneurysm. Orthologous to human MYLK (myosin light chain kinase). [provided by Alliance of Genome Resources, Apr 2022]