心肌肌膜磷酸肌醇磷脂酶C的一种胞质蛋白激活剂。

A cytosolic protein activator of cardiac sarcolemmal phosphoinositide phospholipase C.

作者信息

Quist E E, Powell P, Quist C, Page S

机构信息

Department of Pharmacology, Texas College of Osteopathic Medicine, Fort Worth 76107.

出版信息

Biochem Biophys Res Commun. 1989 Aug 30;163(1):567-73. doi: 10.1016/0006-291x(89)92175-x.

DOI:10.1016/0006-291x(89)92175-x

PMID:2549998

Abstract

Ca2+ dependent polyphosphoinositide phospholipase C (PLC) activity in cardiac sarcolemma hydrolyzed both endogenous and exogenous phosphatidylinositol 4-phosphate (PIP) and phosphatidylinositol 4,5-bisphosphate (PIP2) with an associated increase in inositol bisphosphate (IP2). Dialyzed cytosol and certain fractions of cytosol isolated by anion exchange or gel filtration chromatography activated sarcolemmal PLC activity by approx. 100%. The PLC activator eluted with an apparent molecular weight of 160 Kdal on a Sephacryl 300 column and was destroyed by heat or trypsin treatment. Exogenous 3H-PIP2 was not hydrolyzed by cytosolic fractions containing sarcolemmal PLC activator. These studies demonstrate that the polyphosphoinositide PLC in cardiac sarcolemma is regulated by a cytosolic protein.

摘要

心肌肌膜中依赖Ca2+的多磷酸肌醇磷脂酶C（PLC）活性可水解内源性和外源性磷脂酰肌醇4-磷酸（PIP）以及磷脂酰肌醇4,5-二磷酸（PIP2），同时伴随着肌醇二磷酸（IP2）的增加。经透析的胞质溶胶以及通过阴离子交换或凝胶过滤色谱法分离得到的某些胞质溶胶组分可使肌膜PLC活性提高约100%。在Sephacryl 300柱上，PLC激活剂以表观分子量160 Kdal被洗脱，并且可被加热或胰蛋白酶处理破坏。含有肌膜PLC激活剂的胞质溶胶组分不会水解外源性3H-PIP2。这些研究表明，心肌肌膜中的多磷酸肌醇PLC受一种胞质蛋白调控。