title: Sbp1p affects translational repression and decapping in Saccharomyces cerevisiae.
abstract: The relationship between translation and mRNA turnover is critical to the regulation of gene expression. One major pathway for mRNA turnover occurs by deadenylation, which leads to decapping and subsequent 5'-to-3' degradation of the body of the mRNA. Prior to mRNA decapping, a transcript exits translation and enters P bodies to become a potential decapping substrate. To understand the transition from translation to decapping, it is important to identify the factors involved in this process. In this work, we identify Sbp1p (formerly known as Ssb1p), an abundant RNA binding protein, as a high-copy-number suppressor of a conditional allele in the decapping enzyme. Sbp1p overexpression restores normal decay rates in decapping-defective strains and increases P-body size and number. In addition, Sbp1p promotes translational repression of mRNA during glucose deprivation. Moreover, P-body formation is reduced in strains lacking Sbp1p. Sbp1p acts in conjunction with Dhh1p, as it is required for translational repression and P-body formation in pat1Delta strains under these conditions. These results identify Sbp1p as a new protein that functions in the transition of mRNAs from translation to an mRNP complex destined for decapping.
authors.affiliation: Department of Molecular Cellular Biology and Howard Hughes Medical Institute, University of Arizona, 1007 E. Lowell St., Tucson, AZ 85721, USA.
authors.forename: Scott P
authors.initials: SP
authors.lastname: Segal
authors.forename: Travis
authors.initials: T
authors.lastname: Dunckley
authors.forename: Roy
authors.initials: R
authors.lastname: Parker
mesh_terms: D000483:Alleles; D053487:DEAD-box RNA Helicases; D004268:DNA-Binding Proteins / Q000235:genetics; D004722:Endoribonucleases / Q000235:genetics* / Q000378:metabolism; D004794:Enzyme Repression; D017353:Gene Deletion; D015966:Gene Expression Regulation, Fungal; D005947:Glucose / Q000378:metabolism; D018840:HSP70 Heat-Shock Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D014176:Protein Biosynthesis / Q000235:genetics*; D039381:RNA Cap-Binding Proteins; D020365:RNA Helicases / Q000235:genetics; D020871:RNA Stability; D012331:RNA, Fungal / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D012261:Ribonucleoproteins / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000737:chemistry / Q000201:enzymology / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D013489:Suppression, Genetic
chemical_list: D004268:DNA-Binding Proteins; D018840:HSP70 Heat-Shock Proteins; C114069:LSM1 protein, S cerevisiae; C103266:PAT1 protein, S cerevisiae; D039381:RNA Cap-Binding Proteins; D012331:RNA, Fungal; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D012261:Ribonucleoproteins; C095192:SSB1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C030052:mRNA decapping enzymes; D004722:Endoribonucleases; C445083:DHH1 protein, S cerevisiae; D053487:DEAD-box RNA Helicases; D020365:RNA Helicases; D005947:Glucose