Cyclic AMP-dependent protein kinase regulates the subcellular localization of Snf1-Sip1 protein kinase

Mol Cell Biol. 2004 Mar;24(5):1836-43. doi: 10.1128/MCB.24.5.1836-1843.2004.

Abstract

The Snf1/AMP-activated protein kinase family has diverse roles in cellular responses to metabolic stress. In Saccharomyces cerevisiae, Snf1 protein kinase has three isoforms of the beta subunit that confer versatility on the kinase and that exhibit distinct patterns of subcellular localization. The Sip1 beta subunit resides in the cytosol in glucose-grown cells and relocalizes to the vacuolar membrane in response to carbon stress. We show that translation of Sip1 initiates at the second ATG of the open reading frame, yielding a potential site for N myristoylation, and that mutation of the critical glycine abolishes relocalization. We further show that the cyclic AMP-dependent protein kinase (protein kinase A [PKA]) pathway maintains the cytoplasmic localization of Sip1 in glucose-grown cells. The Snf1 catalytic subunit also exhibits aberrant localization to the vacuolar membrane in PKA-deficient cells, indicating that PKA regulates the localization of Snf1-Sip1 protein kinase. These findings establish a novel mechanism of regulation of Snf1 protein kinase by the PKA pathway.

Publication types

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

MeSH terms

  • AMP-Activated Protein Kinases
  • Carbon / metabolism
  • Codon
  • Cyclic AMP-Dependent Protein Kinases / genetics
  • Cyclic AMP-Dependent Protein Kinases / metabolism*
  • Cytoplasm / metabolism
  • Fungal Proteins / genetics
  • Fungal Proteins / metabolism*
  • Open Reading Frames
  • Protein Serine-Threonine Kinases / genetics
  • Protein Serine-Threonine Kinases / metabolism*
  • Protein Subunits / metabolism
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Saccharomyces cerevisiae / cytology
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae / metabolism*
  • Saccharomyces cerevisiae Proteins / genetics
  • Saccharomyces cerevisiae Proteins / metabolism*
  • Signal Transduction / physiology
  • Vacuoles / metabolism

Substances

  • Codon
  • Fungal Proteins
  • Protein Subunits
  • Recombinant Fusion Proteins
  • Saccharomyces cerevisiae Proteins
  • Carbon
  • SNF1-related protein kinases
  • Protein Serine-Threonine Kinases
  • SIP1 protein, S cerevisiae
  • Cyclic AMP-Dependent Protein Kinases
  • AMP-Activated Protein Kinases