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Updated: Jun 23, 2026
09:16
Oligopeptide Competition Assay for Phosphorylation Site Determination
Published on: May 18, 2017
SNF1/AMPK controls its own localization by phosphorylating its activating kinase Sak1
Hind Moukham1, Marco Caligaris2, Pauline Six2
1Department of Biotechnology and Biosciences, University of Milano-Bicocca, 20126 Milano, Italy.
Iscience
|June 22, 2026
Summary
The study reveals that the metabolic regulator SNF1/AMPK controls its own movement into the nucleus upon glucose depletion. This self-regulation, dependent on the kinase Sak1, fine-tunes cellular responses to metabolic stress.
Area of Science:
- Molecular Biology
- Cellular Metabolism
- Yeast Genetics
Background:
- SNF1/AMPK is a crucial metabolic regulator in yeast, responding to glucose scarcity.
- Its activation involves phosphorylation by upstream kinases, primarily Sak1.
- Sak1 itself has multiple Snf1-dependent phosphorylation sites.
Purpose of the Study:
- To investigate the nuclear/cytoplasmic dynamics of Snf1 in response to glucose depletion.
- To elucidate the role of Sak1 in regulating Snf1 localization.
- To understand how Snf1's subcellular localization impacts adaptation to metabolic stress.
Main Methods:
- Single-cell live imaging techniques were employed.
- Analysis of Snf1 localization in wild-type and sak1 mutant yeast strains.
- Monitoring of a nuclear Snf1 reporter (ACC1-3xGFP-NLS) phosphorylation.
Main Results:
- Snf1 rapidly enters the nucleus after glucose depletion in a Sak1-dependent manner.
- In a mutant unable to be phosphorylated by Snf1 (sak1 10Ala), Snf1 showed increased nuclear entry, particularly in S/G2/M cells.
- This enhanced nuclear localization correlated with increased reporter phosphorylation and improved adaptation to glucose scarcity.
Conclusions:
- Snf1 can regulate its own subcellular localization in response to metabolic cues.
- Sak1-mediated phosphorylation is critical for controlling Snf1 nuclear entry.
- Fine-tuning of Snf1's subcellular distribution is essential for optimizing its activity and downstream signaling during glucose deprivation.
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