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Roles of the Glycogen-binding Domain and Snf4 in Glucose Inhibition of SNF1 Protein Kinase
- Source :
- Journal of Biological Chemistry. 283:19521-19529
- Publication Year :
- 2008
- Publisher :
- Elsevier BV, 2008.
-
Abstract
- The SNF1/AMP-activated protein kinase (AMPK) family is required for adaptation to metabolic stress and energy homeostasis. The γ subunit of AMPK binds AMP and ATP, and mutations that affect binding cause human disease. We have here addressed the role of the Snf4 (γ) subunit in regulating SNF1 protein kinase in response to glucose availability in Saccharomyces cerevisiae. Previous studies of mutant cells lacking Snf4 suggested that Snf4 counteracts autoinhibition by the C-terminal sequence of the Snf1 catalytic subunit but is dispensable for glucose regulation, and AMP does not activate SNF1 in vitro. We first introduced substitutions at sites that, in AMPK, contribute to nucleotide binding and regulation. Mutations at several sites relieved glucose inhibition of SNF1, as judged by catalytic activity, phosphorylation of the activation-loop Thr-210, and growth assays, although analogs of the severe human mutations R531G/Q had little effect. We further showed that alterations of Snf4 residues that interact with the glycogen-binding domain (GBD) of the β subunit strongly relieved glucose inhibition. Finally, substitutions in the GBD of the Gal83 β subunit that are predicted to disrupt interactions with Snf4 and also complete deletion of the GBD similarly relieved glucose inhibition of SNF1. Analysis of mutant cells lacking glycogen synthase showed that regulation of SNF1 is normal in the absence of glycogen. These findings reveal novel roles for Snf4 and the GBD in regulation of SNF1.
- Subjects :
- Saccharomyces cerevisiae Proteins
Protein subunit
Saccharomyces cerevisiae
AMP-Activated Protein Kinases
Protein Serine-Threonine Kinases
Biochemistry
Protein Structure, Secondary
chemistry.chemical_compound
AMP-activated protein kinase
Multienzyme Complexes
Catalytic Domain
Humans
Phosphorylation
Protein kinase A
Glycogen synthase
Molecular Biology
Glycogen binding
biology
Glycogen
Mechanisms of Signal Transduction
fungi
AMPK
Cell Biology
Protein Structure, Tertiary
carbohydrates (lipids)
Glucose
Glycogen Synthase
Amino Acid Substitution
chemistry
Mutation
biology.protein
Blood sugar regulation
Carrier Proteins
Energy Metabolism
Transcription Factors
Subjects
Details
- ISSN :
- 00219258
- Volume :
- 283
- Database :
- OpenAIRE
- Journal :
- Journal of Biological Chemistry
- Accession number :
- edsair.doi.dedup.....5da619844f6333cb9e5a047a779d5e31