REG1 binds to protein phosphatase type 1 and regulates glucose repression in Saccharomyces cerevisiae

EMBO J. 1995 Dec 1;14(23):5939-46.

Abstract

Protein phosphatase type 1 (PP1) is encoded by GLC7, an essential gene in Saccharomyces cerevisiae. The GLC7 phosphatase is required for glucose repression and appears to function antagonistically to the SNF1 protein kinase. Previously, we characterized a mutation, glc7-T152K, that relieves glucose repression but does not interfere with the function of GLC7 in glycogen metabolism. We proposed that the mutant GLC7T152K phosphatase is defective in its interaction with a regulatory subunit that directs participation of PP1 in the glucose repression mechanism. Here, we present evidence that REG1, a protein required for glucose repression, is one such regulatory subunit. We show that REG1 is physically associated with GLC7. REG1 interacts with GLC7 strongly and specifically in the two-hybrid system, and REG1 and GLC7 fusion proteins co-immunoprecipitate from cell extracts. Moreover, overexpression of a REG1 fusion protein suppresses the glc7-T152K mutant defect in glucose repression. This and other genetic evidence indicate that the two proteins function together in regulating glucose repression. These results suggest that REG1 is a regulatory subunit of PP1 that targets its activity to proteins in the glucose repression regulatory pathway.

Publication types

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

MeSH terms

  • Base Sequence
  • Fungal Proteins / chemistry
  • Fungal Proteins / genetics
  • Fungal Proteins / metabolism*
  • Gene Expression Regulation, Fungal / genetics
  • Glucose / metabolism*
  • Glycogen / metabolism
  • Immunoblotting
  • Molecular Sequence Data
  • Mutation
  • Phosphoprotein Phosphatases / chemistry
  • Phosphoprotein Phosphatases / genetics
  • Phosphoprotein Phosphatases / metabolism*
  • Precipitin Tests
  • Protein Phosphatase 1
  • Recombinant Fusion Proteins / metabolism
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae / metabolism*
  • Saccharomyces cerevisiae Proteins*

Substances

  • Fungal Proteins
  • Recombinant Fusion Proteins
  • Saccharomyces cerevisiae Proteins
  • Glycogen
  • Phosphoprotein Phosphatases
  • Protein Phosphatase 1
  • REG1 protein, S cerevisiae
  • Glucose