Activation and inhibition of Snf1 kinase activity by phosphorylation within the activation loop
| Autor: | Rhonda R. McCartney, Dakshayini G. Chandrashekarappa, Leopold Garnar-Wortzel, Martin C. Schmidt |
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| Rok vydání: | 2016 |
| Předmět: |
0301 basic medicine
Models Molecular Threonine Biophysics Gene Expression Saccharomyces cerevisiae Mitogen-activated protein kinase kinase Protein Serine-Threonine Kinases Biochemistry Protein Structure Secondary Article Analytical Chemistry MAP2K7 03 medical and health sciences Protein Domains Escherichia coli Serine ASK1 Amino Acid Sequence Cloning Molecular Phosphorylation Molecular Biology Protein kinase C Conserved Sequence Serine/threonine-specific protein kinase MAP kinase kinase kinase biology Cyclin-dependent kinase 2 fungi Phosphoproteins Recombinant Proteins carbohydrates (lipids) 030104 developmental biology Amino Acid Substitution Mutation biology.protein Cyclin-dependent kinase 9 Sequence Alignment |
| Zdroj: | Biochimica et biophysica acta. 1864(11) |
| ISSN: | 0006-3002 |
| Popis: | The AMP-activated protein kinase is a metabolic regulator that transduces information about energy and nutrient availability. In yeast, the AMP-activated protein kinase, called Snf1, is activated when energy and nutrients are scarce. Earlier studies have demonstrated that activation of Snf1 requires the phosphorylation of the activation loop on threonine 210. Here we examined the regulation of Snf1 kinase activity in response to phosphorylation at other sites. Phosphoproteomic studies have identified numerous phosphorylation sites within the Snf1 kinase enzyme. We made amino acid substitutions in the Snf1 protein that were either non-phosphorylatable (serine to alanine) or phospho-mimetic (serine to glutamate) and examined the effects of these changes on Snf1 kinase function in vivo and on its catalytic activity in vitro. We found that changes to most of the phosphorylation sites had no effect on Snf1 kinase function. However, changes to serine 214, a site within the kinase activation loop, inhibited Snf1 kinase activity. Snf1-activating kinase 1 still phosphorylates Snf1-S214E on threonine 210 but the S214E enzyme is non-functional in vivo and catalytically inactive in vitro. We conclude that yeast have developed two distinct pathways for down-regulating Snf1 activity. The first is through direct dephosphorylation of the conserved activation loop threonine. The second is through phosphorylation of serine 214. |
| Databáze: | OpenAIRE |
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