ISSN:
1573-6903
Keywords:
Protein kinase C
;
proteolysis
;
calpain
;
phospholipid
;
signal transduction
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract The alpha isoform of protein kinase C (PKCα) is rapidly hydrolyzed by mM Ca2+-requiring calpain (calcium-activated neutral proteinase) under cell-free conditions (Shea et al, 1994, FEBS Lett. 350: 223). In the present study, we demonstrate that this hydrolysis is inhibited by phosphatidyl serine, diacylglycerol, phosphatidyl choline, phosphatidyl inositol, and phosphatidic acid. With the exception of phosphatidic acid, these phospholipids did not directly inhibit calpain activity as evidenced by degradation of [14C]azocasein, suggesting that the nature of inhibition of calpain-mediated PKCα degradation is due to an effect of phospholipids on PKCα conformation. These findings suggest that m calpain-mediated PKCα hydrolysis may be specifically minimized at the plasma membrane, and leave open the possibility that such a mechanism exists in situ. In addition, the unique inhibition of calpain activity by phosphatidic acid suggests the existence of a specific mechanism by which this phospholipid regulates PKCα activity.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00992512
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