title: Characterization of glycogen-deficient glc mutants of Saccharomyces cerevisiae.
abstract: Forty-eight mutants of Saccharomyces cerevisiae with defects in glycogen metabolism were isolated. The mutations defined eight GLC genes, the function of which were determined. Mutations in three of these genes activate the RAS/cAMP pathway either by impairment of a RAS GTPase-activating protein (GLC1/IRA1 and GLC4/IRA2) or by activating Ras2p (GLC5/RAS2). SNF1 protein kinase (GLC2) was found to be required for normal glycogen levels. Glycogen branching enzyme (GLC3) was found to be required for significant glycogen synthesis. GLC6 was shown to be allelic to CIF1 (and probably FDP1, BYP1 and GGS1), mutations in which were previously found to prevent growth on glucose; this gene is also the same as TPS1, which encodes a subunit of the trehalose-phosphate synthase. Mutations in GLC6 were capable of increasing or decreasing glycogen levels, at least in part via effects on the regulation of glycogen synthase. GLC7 encodes a type 1 protein phosphatase that contributes to the dephosphorylation (and hence activation) of glycogen synthase. GLC8 encodes a homologue of type 1 protein phosphatase inhibitor-2. The genetic map positions of GLC1/IRA1, GLC3, GLC4/IRA2, GLC6/CIF1/TPS1 (and the adjacent VAT2/VMA2), and GLC7 were clarified. From the data on GLC3, there may be a suppression of recombination near the chromosome V centromere, at least in some strains.
authors.affiliation: Department of Molecular Microbiology and Immunology, University of Missouri-Columbia, School of Medicine 65212.
authors.forename: J F
authors.initials: JF
authors.lastname: Cannon
authors.forename: J R
authors.initials: JR
authors.lastname: Pringle
authors.forename: A
authors.initials: A
authors.lastname: Fiechter
authors.forename: M
authors.initials: M
authors.lastname: Khalil
mesh_terms: D015061:1,4-alpha-Glucan Branching Enzyme / Q000235:genetics; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D004791:Enzyme Inhibitors; D005656:Fungal Proteins; D020690:GTPase-Activating Proteins; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal; D005964:Glucosyltransferases / Q000235:genetics / Q000378:metabolism; D006003:Glycogen / Q000096:biosynthesis*; D008969:Molecular Sequence Data; D016296:Mutagenesis; D010749:Phosphoprotein Phosphatases / Q000235:genetics; D017346:Protein Serine-Threonine Kinases / Q000235:genetics; D011506:Proteins / Q000235:genetics; D011817:Rabbits; D012097:Repressor Proteins; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014199:Trehalose / Q000378:metabolism; D018631:ras Proteins; D000097847:Protein Phosphatase Inhibitory Proteins
chemical_list: D015061:1,4-alpha-Glucan Branching Enzyme; D004791:Enzyme Inhibitors; D005656:Fungal Proteins; D020690:GTPase-Activating Proteins; D005964:Glucosyltransferases; D006003:Glycogen; D010749:Phosphoprotein Phosphatases; D017346:Protein Serine-Threonine Kinases; D011506:Proteins; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins; D014199:Trehalose; D018631:ras Proteins; C086675:GLC8 protein, S cerevisiae; C065725:IRA1 protein, S cerevisiae; C064960:IRA2 protein, S cerevisiae; C024833:protein phosphatase inhibitor-2; D000097847:Protein Phosphatase Inhibitory Proteins; C023180:trehalose-6-phosphate synthase; C086676:GLC3 protein, S cerevisiae; C071570:SNF1-related protein kinases; C489015:RAS2 protein, S cerevisiae