Glucose repression/derepression in budding yeast: SNF1 protein kinase is activated by phosphorylation under derepressing conditions, and this correlates with a high AMP:ATP ratio

摘要: Abstract Background Genetic studies of Saccharomyces cerevisiae have shown that Snf1p and Snf4p, which together form the SNF1 complex, are essential for gene derepression on removal glucose from medium. However metabolic signal(s) involved, exact role SNF1, remained enigmatic. Recently, AMP-activated protein kinase (AMPK) was to be mammalian homologue SNF1. AMPK is activated by elevation cellular AMP:ATP ratio, occurs during stress in cells. The mechanism activation involves phosphorylation an upstream (AMPKK). We investigated whether a similar might explain yeast response starvation. Results activity dramatically rapidly not directly AMP, but could inactivated phosphatases reactivated AMPKK. also demonstrated endogenous SNF1-reactivating factor, most likely kinase, present extracts. Under variety different growth conditions, there correlation between adenine nucleotide levels state Conclusions Apart lack direct allosteric regulation cascades highly conserved. Adenine nucleotides now good candidates signals indicate medium, triggering glucose-repressed genes.