The role of phosphorylation in the interaction of rabbit muscle phosphofructokinase with F-actin

M. A. Luther, J. C. Lee

Research output: Contribution to journalArticle

90 Scopus citations

Abstract

The role of phosphorylation in the regulation of rabbit muscle phosphofructokinase was investigated by monitoring the effect of this covalent modification on the steady-state kinetics and complex formation between F-actin and the enzyme. Binding of phosphofructokinase to F-actin at pH 7.0 and 23° C was monitored by sedimentation. These experiments show that phosphorylated phosphofructokinase has a higher apparent affinity for F-actin than does the dephosphorylated form. Control experiments showed that the complex formation is specific. Steady-state kinetic measurements at pH 7.0, 23°C, showed that the presence of F-actin did not significantly affect the basic kinetic properties of the dephosphorylated form. Under identical conditions, F-actin acted as a positive effector of the phosphorylated form, and the effect of F-actin is specific. Results from these in vitro studies are consistent with in vivo observations which show that upon stimulation of muscle contraction, the enzyme is phosphorylated to a greater extent and the binding to the muscle matrix is increased. Hence, phosphorylation of phosphofructokinase does not only alter the kinetic behavior of the enzyme, but also serves as a means to regulate the compartmentalization of the enzyme in order to provide energy to the cellular component where it is needed.

Original languageEnglish (US)
Pages (from-to)1753-1759
Number of pages7
JournalJournal of Biological Chemistry
Volume261
Issue number4
StatePublished - Dec 1 1986

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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