刷状缘钙调蛋白依赖性肌球蛋白重链和轻链激酶对刷状缘肌球蛋白的磷酸化作用。

Phosphorylation of brush border myosin by brush border calmodulin-dependent myosin heavy and light chain kinases.

作者信息

Rieker J P, Collins J H

机构信息

Department of Microbiology, Biochemistry and Molecular Biology, School of Medicine, University of Pittsburgh, PA 15261.

出版信息

FEBS Lett. 1987 Nov 2;223(2):262-6. doi: 10.1016/0014-5793(87)80301-0.

DOI:10.1016/0014-5793(87)80301-0

PMID:2959565

Abstract

Calmodulin-dependent myosin light chain kinase isolated from chicken intestinal brush border phosphorylates brush border myosin at an apparently single serine identical to that phosphorylated by smooth muscle myosin light chain kinase. Phosphorylation to 1.8 mol phosphate/mol myosin activated the myosin actin-activated ATPase about 10-fold, to about 50 nmol/min per mg. Myosin phosphorylated on its light chains could then be further phosphorylated to a total of 3.2 mol phosphate per mol by brush border calmodulin-dependent heavy chain kinase. Heavy chain phosphorylation did not alter the actin-activated ATPase of either myosin prephosphorylated on its light chains or of unphosphorylated myosin.

摘要

从鸡小肠刷状缘分离得到的钙调蛋白依赖性肌球蛋白轻链激酶，可使刷状缘肌球蛋白在一个明显单一的丝氨酸位点发生磷酸化，该位点与平滑肌肌球蛋白轻链激酶磷酸化的位点相同。每摩尔肌球蛋白磷酸化至1.8摩尔磷酸时，可使肌球蛋白肌动蛋白激活的ATP酶活性提高约10倍，达到约每毫克每分钟50纳摩尔。轻链磷酸化的肌球蛋白随后可被刷状缘钙调蛋白依赖性重链激酶进一步磷酸化，使每摩尔肌球蛋白的磷酸总量达到3.2摩尔。重链磷酸化不会改变轻链预先磷酸化的肌球蛋白或未磷酸化肌球蛋白的肌动蛋白激活的ATP酶活性。