title: Inappropriate translation inhibition and P-body formation cause cold-sensitivity in tryptophan-auxotroph yeast mutants.
abstract: In response to different adverse conditions, most eukaryotic organisms, including Saccharomyces cerevisiae, downregulate protein synthesis through the phosphorylation of eIF2α (eukaryotic initiation factor 2α) by Gcn2, a highly conserved protein kinase. Gcn2 also controls the translation of Gcn4, a transcription factor involved in the induction of amino acid biosynthesis enzymes. Here, we have studied the functional role of Gcn2 and Gcn2-regulating proteins, in controlling translation during temperature downshifts of TRP1 and trp1 yeast cells. Our results suggest that neither cold-instigated amino acid limitation nor Gcn2 are involved in the translation suppression at low temperature. However, loss of TRP1 causes increased eIF2α phosphorylation, Gcn2-dependent polysome disassembly and overactivity of Gcn4, which result in cold-sensitivity. Indeed, knock-out of GCN2 improves cold growth of trp1 cells. Likewise, mutation of several Gcn2-regulators and effectors results in cold-growth effects. Remarkably, we found that Hog1, the osmoresponsive MAPK, plays a role in the regulatory mechanism of Gcn2-eIF2α. Finally, we demonstrated that P-body formation responds to a downshift in temperature in a TRP1-dependent manner and is required for cold tolerance.
authors.affiliation: Department of Biotechnology, Instituto de Agroquímica y Tecnología de los Alimentos, Consejo Superior de Investigaciones Científicas, Avda. Agustín Escardino, 7, 46980-Paterna, Valencia, Spain.
authors.forename: Lidia
authors.initials: L
authors.lastname: Ballester-Tomás
authors.affiliation: Department of Biotechnology, Instituto de Agroquímica y Tecnología de los Alimentos, Consejo Superior de Investigaciones Científicas, Avda. Agustín Escardino, 7, 46980-Paterna, Valencia, Spain.
authors.forename: Jose A
authors.initials: JA
authors.lastname: Prieto
authors.affiliation: Departament of Biochemistry and Molecular Biology, ERI Biotecmed, Universitat de València, Dr. Moliner 50, Burjassot 46100, Spain.
authors.forename: Paula
authors.initials: P
authors.lastname: Alepuz
authors.affiliation: Biozentrum, University of Basel, Basel, Switzerland.
authors.forename: Asier
authors.initials: A
authors.lastname: González
authors.affiliation: Department of Biotechnology, Instituto de Agroquímica y Tecnología de los Alimentos, Consejo Superior de Investigaciones Científicas, Avda. Agustín Escardino, 7, 46980-Paterna, Valencia, Spain.
authors.forename: Elena
authors.initials: E
authors.lastname: Garre
authors.affiliation: Department of Biotechnology, Instituto de Agroquímica y Tecnología de los Alimentos, Consejo Superior de Investigaciones Científicas, Avda. Agustín Escardino, 7, 46980-Paterna, Valencia, Spain. Electronic address: randez@iata.csic.es.
authors.forename: Francisca
authors.initials: F
authors.lastname: Randez-Gil
mesh_terms: D000222:Adaptation, Physiological; D050976:Basic-Leucine Zipper Transcription Factors / Q000378:metabolism; D003080:Cold Temperature; D004734:Energy Metabolism; D039642:Eukaryotic Initiation Factors / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D010766:Phosphorylation; D014176:Protein Biosynthesis; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism; D014364:Tryptophan / Q000235:genetics* / Q000378:metabolism
chemical_list: D050976:Basic-Leucine Zipper Transcription Factors; D039642:Eukaryotic Initiation Factors; C501391:GCN4 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C561842:TORC1 protein complex, S cerevisiae; D014157:Transcription Factors; D014364:Tryptophan; C512912:GCN2 protein, S cerevisiae; D017346:Protein Serine-Threonine Kinases; C088589:HOG1 protein, S cerevisiae; D020928:Mitogen-Activated Protein Kinases
keywords: Gcn2 pathway; Hog1; Low temperature; Polysomes; Snf1; Yeast; eIF2α