Phosphorylation sites linked to glial filament disassembly in vitro locate in a non-alpha-helical head domain

J Biol Chem. 1990 Mar 15;265(8):4722-9.

Abstract

Glial fibrillary acidic protein (GFAP), the intermediate filament component of astroglial cells, can serve as an excellent substrate for both cAMP-dependent protein kinase and protein kinase C, in vitro. GFAP phosphorylated by each protein kinase does not polymerize, and the filaments that do polymerize tend to depolymerize after phosphorylation. Dephosphorylation of phospho-GFAP by phosphatase led to a recovery of the polymerization competence of GFAP. Most of the phosphorylation sites for cAMP-dependent protein kinase and protein kinase C on GFAP are the same, Ser-8, Ser-13, and Ser-34. cAMP-dependent protein kinase has one additional phosphorylation site, Thr-7. All the sites are located within the amino-terminal non-alpha-helical head domain of GFAP. These observations pave the way for in vivo studies on organization of glial filaments.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Binding Sites
  • Brain Chemistry
  • Cattle
  • Cyclic AMP / pharmacology
  • Cytoskeleton / metabolism*
  • Desmin / metabolism
  • Glial Fibrillary Acidic Protein / metabolism*
  • Hydrogen-Ion Concentration
  • Intermediate Filaments / metabolism*
  • Intermediate Filaments / ultrastructure
  • Kinetics
  • Microscopy, Electron
  • Neuroglia / ultrastructure*
  • Phosphates / metabolism*
  • Phosphorylation
  • Polymers / metabolism
  • Protein Kinase C / metabolism
  • Protein Kinases / metabolism
  • Rats
  • Swine
  • Vimentin / metabolism

Substances

  • Desmin
  • Glial Fibrillary Acidic Protein
  • Phosphates
  • Polymers
  • Vimentin
  • Cyclic AMP
  • Protein Kinases
  • Protein Kinase C