title: Dosage-dependent modulation of glucose repression by MSN3 (STD1) in Saccharomyces cerevisiae.
abstract: The SNF1 protein kinase of Saccharomyces cerevisiae is required to relieve glucose repression of transcription. To identify components of the SNF1 pathway, we isolated multicopy suppressors of defects caused by loss of SNF4, an activator of the SNF1 kinase. Increased dosage of the MSN3 gene restored invertase expression in snf4 mutants and also relieved glucose repression in the wild type. Deletion of MSN3 caused no substantial phenotype, and we identified a homolog, MTH1, encoding a protein 61% identical to MSN3. Both are also homologous to chicken fimbrin, human plastin, and yeast SAC6 over a 43-residue region. Deletion of MSN3 and MTH1 together impaired derepression of invertase in response to glucose limitation. Finally, MSN3 physically interacts with the SNF1 protein kinase, as assayed by a two-hybrid system and by in vitro binding studies. MSN3 is the same gene as STD1, a multicopy suppressor of defects caused by overexpression of the C terminus of TATA-binding protein (R. W. Ganster, W. Shen, and M. C. Schmidt, Mol. Cell. Biol. 13:3650-3659, 1993). Taken together, these data suggest that MSN3 modulates the regulatory response to glucose and may couple the SNF1 pathway to transcription.
authors.affiliation: Department of Genetics and Development, College of Physicians and Surgeons of Columbia University, New York, New York 10032.
authors.forename: E J
authors.initials: EJ
authors.lastname: Hubbard
authors.forename: R
authors.initials: R
authors.lastname: Jiang
authors.forename: M
authors.initials: M
authors.lastname: Carlson
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000595:Amino Acid Sequence; D003001:Cloning, Molecular; D017931:DNA Primers / Q000737:chemistry; D005337:Fibrin / Q000737:chemistry; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics* / Q000502:physiology*; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal; D005947:Glucose / Q000378:metabolism*; D047908:Intracellular Signaling Peptides and Proteins; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D008840:Microfilament Proteins; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D010750:Phosphoproteins / Q000737:chemistry; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics; D011993:Recombinant Fusion Proteins; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014158:Transcription, Genetic
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D017931:DNA Primers; D005656:Fungal Proteins; D047908:Intracellular Signaling Peptides and Proteins; C118806:MTH1 protein, S cerevisiae; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D008840:Microfilament Proteins; D010750:Phosphoproteins; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; C081335:STD1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C026742:plastin; D005337:Fibrin; C071570:SNF1-related protein kinases; D017346:Protein Serine-Threonine Kinases; D005947:Glucose