title: Receptor for activated C-kinase (RACK1) homolog Cpc2 facilitates the general amino acid control response through Gcn2 kinase in fission yeast.
abstract: General amino acid control (GAAC) is crucial for sensing and adaptation to nutrient availability. Amino acid starvation activates protein kinase Gcn2, which plays a central role in the GAAC response by phosphorylating the α-subunit of eukaryotic initiation factor 2 (eIF2α), leading to the translational switch to stimulate selective expression of stress-responsive genes. We report here that in fission yeast Schizosaccharomyces pombe, Cpc2, a homolog of mammalian receptor for activated C-kinase (RACK1), is important for the GAAC response. Deletion of S. pombe cpc2 impairs the amino acid starvation-induced phosphorylation of eIF2α and the expression of amino acid biosynthesis genes, thereby rendering cells severely sensitive to amino acid limitation. Unlike the Saccharomyces cerevisiae Cpc2 ortholog, which normally suppresses the GAAC response, our findings suggest that S. pombe Cpc2 promotes the GAAC response. We also found that S. pombe Cpc2 is required for starvation-induced Gcn2 autophosphorylation, which is essential for Gcn2 function. These results indicate that S. pombe Cpc2 facilitates the GAAC response through the regulation of Gcn2 activation and provide a novel insight for the regulatory function of RACK1 on Gcn2-mediated GAAC response.
authors.affiliation: Department of Gene Mechanisms, Graduate School of Biostudies, Kyoto University, Yoshida-Konoe-cho, Sakyo-ku, Kyoto 606-8501, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Tarumoto
authors.forename: Junko
authors.initials: J
authors.lastname: Kanoh
authors.forename: Fuyuki
authors.initials: F
authors.lastname: Ishikawa
mesh_terms: D000596:Amino Acids / Q000378:metabolism; D002499:Centrifugation, Density Gradient; D015852:Eukaryotic Initiation Factor-2 / Q000378:metabolism; D010766:Phosphorylation; D014176:Protein Biosynthesis; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D000075370:Receptors for Activated C Kinase; D011956:Receptors, Cell Surface / Q000378:metabolism*; D012270:Ribosomes / Q000378:metabolism; D012568:Schizosaccharomyces / Q000378:metabolism*; D029702:Schizosaccharomyces pombe Proteins / Q000378:metabolism*; D015398:Signal Transduction; D013395:Sucrose
chemical_list: D000596:Amino Acids; D015852:Eukaryotic Initiation Factor-2; D000075370:Receptors for Activated C Kinase; D011956:Receptors, Cell Surface; D029702:Schizosaccharomyces pombe Proteins; C000617313:cpc2 protein, S pombe; D013395:Sucrose; C539007:Gcn2 protein, S pombe; D017346:Protein Serine-Threonine Kinases
keywords: Cpc2; Gcn2; General Amino Acid Control; Phosphorylation; Signal Transduction; Stress Response; Translation Control; Yeast