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Calcium/phosphatidylserine/diacylglycerol-dependent protein phosphorylation in the Aplysia nervous system.

Abstract
It has been shown that intracellular injection of protein kinase C (calcium/phosphatidylserine/diacylglycerol-dependent protein kinase), purified from mammalian brain, or application of the tumor-promoting phorbol diester, 12-O-tetradecanoyl-13-phorbol acetate (TPA), leads to an enhancement of calcium currents in the bag cell neurons of Aplysia. We now present evidence of an endogenous enzyme in bag cell neurons which is activated by TPA and which has properties similar to those of mammalian protein kinase C. Calcium/phosphatidylserine/diacylglycerol-dependent protein kinase activity was found in both cytosolic and particulate fractions prepared from isolated clusters of bag cell neurons. This endogenous enzyme phosphorylated an 87,000-dalton protein from bovine brain, which appears to be a specific substrate for protein kinase C, as well as several substrates present in cytosolic fractions prepared from isolated bag cell clusters. Similar results were obtained using preparations made from pooled head ganglia from Aplysia. The pharmacological properties of the calcium/phosphatidylserine/diacylglycerol-dependent protein kinase activity in the Aplysia nervous system were similar to those of protein kinase C from mammalian tissues. Thus, the same group of endogenous substrate proteins were phosphorylated when diacylglycerol was replaced by TPA in cytosolic fractions prepared from isolated bag cell clusters. Non-tumor-promoting phorbols (4-alpha-phorbol, 4-alpha-phorbol-12,13-didecanoate, and 4-O-methyl-12-O-tetradecanoylphorbol-13-acetate) did not stimulate protein phosphorylation in these preparations. Phosphorylation by the Aplysia calcium/phosphatidylserine/diacylglycerol-dependent protein kinase was inhibited by polymixin B sulfate, by calmodulin, and by the "calmodulin antagonists" trifluoperazine, calmidazolium and W7.(ABSTRACT TRUNCATED AT 250 WORDS)
AuthorsS A DeRiemer, P Greengard, L K Kaczmarek
JournalThe Journal of neuroscience : the official journal of the Society for Neuroscience (J Neurosci) Vol. 5 Issue 10 Pg. 2672-6 (Oct 1985) ISSN: 0270-6474 [Print] United States
PMID4045549 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, Non-P.H.S., Research Support, U.S. Gov't, P.H.S.)
Chemical References
  • Diglycerides
  • Glycerides
  • Nerve Tissue Proteins
  • Phosphatidylserines
  • Protein Kinases
  • Calcium
Topics
  • Aplysia
  • Calcium (physiology)
  • Diglycerides (physiology)
  • Glycerides (physiology)
  • Nerve Tissue Proteins (metabolism)
  • Nervous System (metabolism)
  • Neurons (metabolism)
  • Phosphatidylserines (physiology)
  • Phosphorylation
  • Protein Kinases (metabolism, pharmacology, physiology)

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