Identification of three in vivo phosphorylation sites on the glycogen-binding subunit of protein phosphatase 1 from rabbit skeletal muscle, and their response to adrenaline

FEBS Lett. 1990 Jan 1;259(2):281-5. doi: 10.1016/0014-5793(90)80027-g.

Abstract

The in vivo phosphorylation stoichiometries of 4 serines on the glycogen-binding (G)-subunit of protein phosphatase 1 (PP1) have been determined. In fed rabbits injected with propranolol stoichiometries (mol/mol) were: site 1 (0.67 +/- 0.09), site 2 (0.20 +/- 0.07), site 3a (0.23 +/- 0.01) and site 3b (0). After injection with adrenalin they became: site 1 (0.90 +/- 0.02), site 2 (0.72 +/- 0.01), site 3a (0.23 +/- 0.02) and site 3b (0). These results, together with other data, establish that site 2 phosphorylation by cyclic AMP-dependent protein kinase triggers dissociation of PP1 from the G-subunit in vivo. They also demonstrate that a residue phosphorylated in vitro by glycogen synthase kinase 3 (site 3a) is phosphorylated in vivo.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Binding Sites
  • Epinephrine / pharmacology*
  • Glycogen / metabolism*
  • Kinetics
  • Macromolecular Substances
  • Molecular Sequence Data
  • Muscles / enzymology*
  • Peptide Mapping
  • Phosphopeptides / isolation & purification
  • Phosphoprotein Phosphatases / metabolism*
  • Phosphorylation
  • Propranolol / pharmacology
  • Protein Phosphatase 1
  • Rabbits
  • Trypsin

Substances

  • Macromolecular Substances
  • Phosphopeptides
  • Glycogen
  • Propranolol
  • Phosphoprotein Phosphatases
  • Protein Phosphatase 1
  • Trypsin
  • Epinephrine