title: Kinetics of Formation and Asymmetrical Distribution of Hsp104-Bound Protein Aggregates in Yeast.
abstract: Budding yeast cells have a finite replicative life span; that is, a mother cell produces only a limited number of daughter cells before it slows division and dies. Despite the gradual aging of the mother cell, all daughters are born rejuvenated and enjoy a full replicative lifespan. It has been proposed that entry of mother cells into senescence is driven by the progressive accumulation and retention of damaged material, including protein aggregates. This additionally allows the daughter cells to be born damage free. However, the mechanism underlying such asymmetrical segregation of protein aggregates by mother and daughter cells remains controversial, in part because of the difficulties inherent in tracking the dynamics and fate of protein aggregates in vivo. To overcome such limitations, we have developed single-cell real-time imaging methodology to track the formation of heat-induced protein aggregates in otherwise unperturbed dividing cells. By combining the imaging data with a simple computational model of protein aggregation, we show that the establishment of asymmetrical partitioning of protein aggregates upon division is driven by the large bud-specific dilution rate associated with polarized growth and the absence of significant mother/bud exchange of protein aggregates during the budded phase of the cell cycle. To our knowledge, this study sheds new light on the mechanism of establishment of a segregation bias, which can be accounted for by simple physical arguments.
authors.affiliation: Development and Stem Cells Department, IGBMC, CNRS UMR 7104, INSERM U964, Université de Strasbourg, Illkirch, France.
authors.forename: Camille
authors.initials: C
authors.lastname: Paoletti
authors.affiliation: Development and Stem Cells Department, IGBMC, CNRS UMR 7104, INSERM U964, Université de Strasbourg, Illkirch, France.
authors.forename: Sophie
authors.initials: S
authors.lastname: Quintin
authors.affiliation: Development and Stem Cells Department, IGBMC, CNRS UMR 7104, INSERM U964, Université de Strasbourg, Illkirch, France.
authors.forename: Audrey
authors.initials: A
authors.lastname: Matifas
authors.affiliation: Development and Stem Cells Department, IGBMC, CNRS UMR 7104, INSERM U964, Université de Strasbourg, Illkirch, France. Electronic address: charvin@igbmc.fr.
authors.forename: Gilles
authors.initials: G
authors.lastname: Charvin
mesh_terms: D002455:Cell Division; D006360:Heat-Shock Proteins / Q000737:chemistry* / Q000378:metabolism*; D007700:Kinetics; D066329:Protein Aggregates; D021381:Protein Transport; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry* / Q000378:metabolism*; D013696:Temperature
chemical_list: D006360:Heat-Shock Proteins; D066329:Protein Aggregates; D029701:Saccharomyces cerevisiae Proteins; C070972:HsP104 protein, S cerevisiae