title: The yeast kinase Swe1 is required for proper entry into cell cycle after arrest due to ribosome biogenesis and protein synthesis defects.
abstract: Sda1 is an essential protein required for cell cycle progression in Saccharomyces cerevisiae. Here, we show that the sda1-1 mutation causes a defect in the formation and nuclear export of 60S ribosomal subunits. Moreover, the sda1-1, but also other mutants defective in ribosome biogenesis (e.g., rix1-1 and tif6Delta), exhibit a G1 arrest, which could be the consequence of impaired ribosome biogenesis. Interestingly, additional deletion of the non-essential Swe1 kinase, the homolog of S. pombe Wee1, causes a pronounced delay in entering a new cell cycle in sda1-1, rix1-1 and tif6Delta cells, when shifted back from restrictive to permissive conditions. However, such a prolonged delay is independent of the Tyr19 phosphorylation in Cdc28. Moreover, the lack of Swe1 causes delay in budding and DNA replication in cells released from the G1 arrest due to the block of protein synthesis. Our data suggest that Swe1 is required for timely entry into cell cycle after a G1 arrest caused by impairment in pre-60S biogenesis and in protein synthesis. Therefore we propose that Swe1, which is required for coordination of cell growth and cell division in G2/M, also has a role in the beginning of the cell cycle.
authors.affiliation: Dipartimento di Scienze Biomolecolari e Biotecnologie, Università di Milano, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Saracino
authors.forename: Jochen
authors.initials: J
authors.lastname: Bassler
authors.forename: Diego
authors.initials: D
authors.lastname: Muzzini
authors.forename: Ed
authors.initials: E
authors.lastname: Hurt
authors.forename: Maria Luisa
authors.initials: ML
authors.lastname: Agostoni Carbone
mesh_terms: D017489:CDC28 Protein Kinase, S cerevisiae / Q000378:metabolism; D002453:Cell Cycle / Q000502:physiology*; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D014176:Protein Biosynthesis; D011505:Protein-Tyrosine Kinases / Q000235:genetics / Q000378:metabolism*; D012270:Ribosomes / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D013696:Temperature
chemical_list: D018797:Cell Cycle Proteins; D009687:Nuclear Proteins; C409685:SDA1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C099685:SWE1 protein, S cerevisiae; D011505:Protein-Tyrosine Kinases; D017489:CDC28 Protein Kinase, S cerevisiae