Phosphodiesteratic breakdown of endogenous polyphosphoinositides in nerve ending membranes |
| |
Authors: | L A Van Rooijen E B Seguin B W Agranoff |
| |
Institution: | 1. Neuroscience Laboratory, University of Michigan, 1103 East Huron, Ann Arbor, MI 48109 USA;2. Department of Biological Chemistry, University of Michigan, 1103 East Huron, Ann Arbor, MI 48109 USA |
| |
Abstract: | When a membrane preparation, obtained by freezing and thawing nerve endings labeled by preincubation with 32pi, is incubated in the presence of millimolar Ca2+, there is a rapid and selective loss of label from the polyphosphoinositides and a concomitant increase in labeled inositol di- and triphosphates recovered. When the membranes are not prelabeled and are exposed to gamma-32P]ATP under similar conditions, phosphatidate labeling is enhanced, indicating increased availability of diacylglycerol. These observations provide evidence for the presence of membrane-bound, Ca2+-stimulated phosphodiesterase activity (phospholipase C) acting on endogenous polyphosphoinositides. The implications of these findings are discussed in respect to the "phosphatidylinositol" cycle. |
| |
Keywords: | Phosphatidylinositol PhI phosphatidylinositol 4 5-bisphosphate inositol triphosphate phosphatidylinositol 4-phosphate PhIP inositol diphosphate phosphatidic acid PhA |
本文献已被 ScienceDirect 等数据库收录! |
|