title: Cellular stress induces cytoplasmic RNA granules in fission yeast.
abstract: Severe stress causes plant and animal cells to form large cytoplasmic granules containing RNA and proteins. Here, we demonstrate the existence of stress-induced cytoplasmic RNA granules in Schizosaccharomyces pombe. Homologs to several known protein components of mammalian processing bodies and stress granules are found in fission yeast RNA granules. In contrast to mammalian cells, poly(A)-binding protein (Pabp) colocalizes in stress-induced granules with decapping protein. After glucose deprivation, protein kinase A (PKA) is required for accumulation of Pabp-positive granules and translational down-regulation. This is the first demonstration of a role for PKA in RNA granule formation. In mammals, the translation initiation protein eIF2α is a key regulator of formation of granules containing poly(A)-binding protein. In S. pombe, nonphosphorylatable eIF2α does not block but delays granule formation and subsequent clearance after exposure to hyperosmosis. At least two separate pathways in S. pombe appear to regulate stress-induced granules: pka1 mutants are fully proficient to form granules after hyperosmotic shock; conversely, eIF2α does not affect granule formation in glucose starvation. Further, we demonstrate a Pka1-dependent link between calcium perturbation and RNA granules, which has not been described earlier in any organism.
authors.affiliation: Department of Cell and Molecular Biology, Lundberg Laboratory, University of Gothenburg, S-405 30 Göteborg, Sweden.
authors.forename: Daniel
authors.initials: D
authors.lastname: Nilsson
authors.forename: Per
authors.initials: P
authors.lastname: Sunnerhagen
mesh_terms: D002118:Calcium / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000235:genetics / Q000378:metabolism; D003594:Cytoplasmic Granules / Q000235:genetics*; D005947:Glucose / Q000378:metabolism; D017403:In Situ Hybridization; D018384:Oxidative Stress; D010766:Phosphorylation; D016133:Polymerase Chain Reaction; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D012313:RNA / Q000235:genetics* / Q000378:metabolism; D012568:Schizosaccharomyces / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics / Q000378:metabolism; D019892:eIF-2 Kinase / Q000235:genetics / Q000378:metabolism
chemical_list: C508496:Dcp2 protein, S pombe; D029702:Schizosaccharomyces pombe Proteins; D012313:RNA; C539007:Gcn2 protein, S pombe; D017346:Protein Serine-Threonine Kinases; D019892:eIF-2 Kinase; D017868:Cyclic AMP-Dependent Protein Kinases; D005947:Glucose; D002118:Calcium