Tang D C, Kubota Y, Kamm K E, Stull J T
Department of Physiology, University of Texas Southwestern Medical Center at Dallas 75235-9040.
FEBS Lett. 1993 Oct 4;331(3):272-5. doi: 10.1016/0014-5793(93)80351-t.
Phosphorylation of myosin light chain kinase by a Ca(2+)-dependent protein kinase increases the concentration of Ca2+/calmodulin required for half-maximal activation. The Ca2+ concentrations required for myosin light chain kinase phosphorylation in permeable smooth muscle are similar to those required for myosin light chain phosphorylation. Both GTP gamma S and carbachol increase the Ca2+ sensitivity of myosin light chain kinase phosphorylation as well as light chain phosphorylation. It is proposed that a similar G-protein mediated mechanism regulates the Ca(2+)-dependent phosphorylation of these two contractile proteins in smooth muscle.
肌球蛋白轻链激酶被一种钙依赖蛋白激酶磷酸化后，半最大激活所需的Ca2+/钙调蛋白浓度会增加。可渗透平滑肌中肌球蛋白轻链激酶磷酸化所需的Ca2+浓度与肌球蛋白轻链磷酸化所需的浓度相似。GTPγS和卡巴胆碱都会增加肌球蛋白轻链激酶磷酸化以及轻链磷酸化的Ca2+敏感性。有人提出，一种类似的G蛋白介导机制调节平滑肌中这两种收缩蛋白的钙依赖磷酸化。
