Roles of the Snf1/Rkin1/AMP-activated protein kinase family in the response to environmental and nutritional stress.

The AMP-activated protein kinase (AMPK) inhibits several biosynthetic pathways in mammals, and is activated in response to stresses which cause ATP depletion, e.g. heat shock. This system may therefore protect cells against environmental stress by switching off biosynthesis (i.e. growth) to conserve ATP. Recent biochemical and molecular genetic studies have shown that AMPK is closely related to the SNF1 gene product from Saccharomyces cerevisiae, and its homologues in higher plants. SNF1 is required for the response to starvation for glucose. Thus the novel function of providing protection against environmental stress may have evolved from a more ancient response to nutritional stress.