The phosphorylation of choline acetyltransferase

Gordon Bruce, Louis B. Hersh

Research output: Contribution to journalArticle

47 Scopus citations

Abstract

Human placental Choline Acetyltransferase (ChAT) has been shown to be phosphorylated in vitro by kinases present in rat brain. Phosphorylation occurs at a single site with the exclusive phosphoamino acid being serine. ChAT phosphorylation was shown to be calcium, and not cyclic nucleotide, dependent and was inhibited by inhibitors of calcium/calmodulin protein kinases including anti-calmodulin anti-sera. ChAT phosphorylation was stimulated by calmodulin (9 fold) and, to a lesser extent, by phosphatidylserine (4 fold). These results indicate the involvement of a calcium/calmodulin and possibly also a calcium/phosopholipid kinase. This finding was confirmed by demonstrating ChAT phosphorylation using both purified multifunctional calcium/calmodulin protein kinase (CaMK) and calcium/phospholipid protein kinase C (PKC) from rat brain. A stoichiometric incorporation of 0.9 mol phosphate/mol ChAT was achieved by CaMK. Phosphorylated ChAT could be isolated from freshly prepared rat brain synaptosomes. The results obtained with this model system support the hypothesis that in vivo a fraction of ChAT exists phosphorylated.

Original languageEnglish (US)
Pages (from-to)613-620
Number of pages8
JournalNeurochemical Research
Volume14
Issue number7
DOIs
StatePublished - Jul 1 1989

Keywords

  • Choline acetyltransferase
  • phosphorylation
  • protein kinase
  • regulation

ASJC Scopus subject areas

  • Biochemistry
  • Cellular and Molecular Neuroscience

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