A Yeast Gene That Is Essential for Release from Glucose Repression Encodes a Protein Kinase

Abstract

The SNF1 gene plays a central role in carbon catabolite repression in the yeast Saccharomyces cerevisiae, namely that SNF1 function is required for expression of glucose-repressible genes. The nucleotide sequence of the cloned SNF1 gene was determined, and the predicted amino acid sequence shows that SNF1 encodes a 72,040-dalton polypeptide that has significant homology to the conserved catalytic domain of mammalian protein kinases. Specific antisera were prepared and used to identify the SNF1 protein. The protein was shown to transfer phosphate from adenosine triphosphate to serine and threonine residues in an in vitro autophosphorylation reaction. These findings indicate that SNF1 encodes a protein kinase and suggest that protein phosphorylation plays a critical role in regulation by carbon catabolite repression in eukaryotic cells.

Role of AMP‐activated protein kinase in the metabolic syndrome and in heart disease

“…Genetic studies of orthologues in lower eukaryotes suggest that the system arose as a Abbreviations: ACC, acetyl-CoA carboxylase; AgRP, agouti-related peptide; AICAR, 5-aminoimidazole-4-carboxamide riboside; AMPK, AMP-activated protein kinase; AS160, Akt substrate of 160 kDa; CaMKK, calmodulin-dependent protein kinase kinase; CBS1-4, cystathionine b-synthase motif 1-4; GLUT4, glucose transporter-4; IRS1, insulin receptor substrate-1; MC4, melanocortin-4; OCT1, organic cation transporter-1; PGC-1a, peroxisome proliferator-activated receptor-c co-activator-1a; POMC, pro-opiomelanocortin; PPAR-c, peroxisome proliferator-activated receptor-c; TSC, tuberous sclerosis complex protective mechanism that allows the organism to survive periods of starvation. The S. cerevisiae orthologue (the SNF1 complex) is required for the response to starvation for its preferred carbon source (glucose) and switches on expression of genes required for metabolism of other carbon sources [4]. It is also required for sporulation, which allows the organism to withstand a period of prolonged starvation.…”

Regulated nuclear translocation of the Mig1 glucose repressor.

“…This model predicts that Snfl has access to Migl and is, therefore, in the nucleus. Snfl has indeed been found throughout the cell (Celenza and Carlson, 1986). Alternatively, it is possible that unphosphorylated (and, therefore, nuclear) Migl is constantly moving between the nucleus and cytoplasm but is phosphorylated by Snfl in the cytoplasm upon removal of glucose and, therefore, trapped there.…”

Transcriptional regulation of the isocitrate lyase encoding gene in Saccharomyces cerevisiae

“…Znjhence of catl/cat3 mutants on ICLl gene expression CATI and CAT3 encode a protein kinase and a subunit necessary for its activity, respectively [24,25]. The complex is needed for derepression of certain genes, including isocitrate lyase, after a shift of cells to nonfermentable carbon sources.…”