Background：

This gene， a muscle member of the immunoglobulin gene superfamily， encodes myosin light chain kinase which is a calcium/calmodulin dependent enzyme. This kinase phosphorylates myosin regulatory light chains to facilitate myosin interaction with actin filaments to produce contractile activity. This gene encodes both smooth muscle and nonmuscle isoforms. In addition， using a separate promoter in an intron in the 3’ region， it encodes telokin， a small protein identical in sequence to the C-terminus of myosin light chain kinase， that is independently expressed in smooth muscle and functions to stabilize unphosphorylated myosin filaments.