ADP regulates SNF1, the Saccharomyces cerevisiae homolog of AMP-activated protein kinase

Cell Metab. 2011 Nov 2;14(5):707-14. doi: 10.1016/j.cmet.2011.09.009. Epub 2011 Oct 20.

Abstract

The SNF1 protein kinase complex plays an essential role in regulating gene expression in response to the level of extracellular glucose in budding yeast. SNF1 shares structural and functional similarities with mammalian AMP-activated protein kinase. Both kinases are activated by phosphorylation on a threonine residue within the activation loop segment of the catalytic subunit. Here we show that ADP is the long-sought metabolite that activates SNF1 in response to glucose limitation by protecting the enzyme against dephosphorylation by Glc7, its physiologically relevant protein phosphatase. We also show that the regulatory subunit of SNF1 has two ADP binding sites. The tighter site binds AMP, ADP, and ATP competitively with NADH, whereas the weaker site does not bind NADH, but is responsible for mediating the protective effect of ADP on dephosphorylation. Mutagenesis experiments suggest that the general mechanism by which ADP protects against dephosphorylation is strongly conserved between SNF1 and AMPK.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Diphosphate / chemistry
  • Adenosine Diphosphate / metabolism*
  • Adenylate Kinase / genetics
  • Adenylate Kinase / metabolism
  • Amino Acid Sequence
  • Catalytic Domain / genetics
  • Conserved Sequence
  • Enzyme Activation / genetics*
  • Gene Expression Regulation, Fungal / physiology
  • Glucose / metabolism*
  • Models, Molecular
  • Molecular Sequence Data
  • Mutation
  • Phosphorylation
  • Protein Interaction Domains and Motifs
  • Protein Phosphatase 1 / genetics
  • Protein Phosphatase 1 / metabolism*
  • Protein-Serine-Threonine Kinases / genetics
  • Protein-Serine-Threonine Kinases / metabolism*
  • Saccharomyces cerevisiae / enzymology*
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae Proteins / genetics
  • Saccharomyces cerevisiae Proteins / metabolism*
  • Signal Transduction*
  • Substrate Specificity
  • Threonine / metabolism

Substances

  • Saccharomyces cerevisiae Proteins
  • Threonine
  • Adenosine Diphosphate
  • SNF1-related protein kinases
  • Protein-Serine-Threonine Kinases
  • Adenylate Kinase
  • GLC7 protein, S cerevisiae
  • Protein Phosphatase 1
  • Glucose