Yeast acetyl-CoA Carboxylase: In Vitro Phosphorylation by Mammalian and Yeast Protein Kinases

Biochem Biophys Res Commun. 1990 Jun 15;169(2):369-76. doi: 10.1016/0006-291x(90)90341-j.

Abstract

Acetyl-CoA carboxylase (ACC) is regulated in mammalian tissues, in part, by multisite enzyme phosphorylation. Yeast ACC (Y-ACC) has been highly purified from S. cerevisiae by monomeric avidin-Sepharose chromatography, revealing an enzyme subunit species of molecular mass 265,000 Da. Unlike mammalian enzyme, Y-ACC is citrate-independent, and reacts weakly or not at all with a panel of anti-rat liver ACC antibodies. Like rat ACC, Y-ACC is rapidly phosphorylated and inactivated by two mammalian carboxylase kinases, the cAMP-dependent protein kinase and 5'-AMP-stimulated kinase. It is also phosphorylated by rat liver casein kinase II, but without any change in catalytic activity. Three major yeast protein kinases active on ACC have been fractionated; all co-elute with kinases active on casein, but each appears to be a distinct catalytic species. Like the mammalian casein kinases, however, phosphorylation of ACC by these yeast kinases does not alter yeast ACC activity. Taken together, these data indicate that Y-ACC possesses at least two classes of phosphorylation sites, one or more of which acutely regulates enzyme activity. Alterations in Y-ACC phosphorylation in yeast, as in mammalian tissues, could be an important modulator of the rates of fatty acid synthesis.

Publication types

  • Comparative Study
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Acetyl-CoA Carboxylase / isolation & purification
  • Acetyl-CoA Carboxylase / metabolism*
  • Animals
  • Chromatography, Gel
  • Chromatography, Ion Exchange
  • Kinetics
  • Ligases / metabolism*
  • Liver / enzymology*
  • Male
  • Molecular Weight
  • Phosphorylation
  • Protein Kinases / isolation & purification
  • Protein Kinases / metabolism*
  • Rats
  • Rats, Inbred Strains
  • Saccharomyces cerevisiae / enzymology*
  • Substrate Specificity

Substances

  • Protein Kinases
  • Ligases
  • Acetyl-CoA Carboxylase