Bultot Laurent, Horman Sandrine, Neumann Dietbert, Walsh Michael P, Hue Louis, Rider Mark H
Université Catholique de Louvain, de Duve Institute, Brussels, Belgium.
FEBS Lett. 2009 Jan 5;583(1):25-8. doi: 10.1016/j.febslet.2008.11.022. Epub 2008 Dec 4.
The kinetics of myosin regulatory light chain (MLC) phosphorylation by recombinant AMP-activated protein kinase (AMPK) were compared with commercial AMPK from rat liver and smooth muscle myosin light chain kinase (smMLCK). With identical amounts of activity units, initial rates of phosphorylation of MLC were at least 100-fold less with recombinant AMPK compared to smMLCK, whereas with rat liver AMPK significant phosphorylation was seen. In Madin-Darby Canine Kidney cells, AMPK activation led to an increase in MLC phosphorylation, which was decreased by a Rho kinase inhibitor without affecting AMPK activation. Therefore, MLC phosphorylation during energy deprivation does not result from direct phosphorylation by AMPK.
将重组AMP活化蛋白激酶（AMPK）使肌球蛋白调节轻链（MLC）磷酸化的动力学与来自大鼠肝脏的商用AMPK和平滑肌肌球蛋白轻链激酶（smMLCK）进行了比较。在活性单位数量相同的情况下，与smMLCK相比，重组AMPK使MLC磷酸化的初始速率至少低100倍，而大鼠肝脏AMPK则出现了显著的磷酸化。在麦迪逊-达比犬肾细胞中，AMPK激活导致MLC磷酸化增加，Rho激酶抑制剂可使其降低，而不影响AMPK激活。因此，能量剥夺期间的MLC磷酸化并非由AMPK直接磷酸化所致。
