scholarly journals Author response: Multiple inputs ensure yeast cell size homeostasis during cell cycle progression

2018 ◽  
Author(s):  
Cecilia Garmendia-Torres ◽  
Olivier Tassy ◽  
Audrey Matifas ◽  
Nacho Molina ◽  
Gilles Charvin
1999 ◽  
Vol 146 (2) ◽  
pp. 373-387 ◽  
Author(s):  
Jana Drgonová ◽  
Tomás Drgon ◽  
Dong-Hyun Roh ◽  
Enrico Cabib

Previous work showed that the GTP-binding protein Rho1p is required in the yeast, Saccharomyces cerevisiae, for activation of protein kinase C (Pkc1p) and for activity and regulation of β(1→3)glucan synthase. Here we demonstrate a hitherto unknown function of Rho1p required for cell cycle progression and cell polarization. Cells of mutant rho1E45I in the G1 stage of the cell cycle did not bud at 37°C. In those cells actin reorganization and recruitment to the presumptive budding site did not take place at the nonpermissive temperature. Two mutants in adjacent amino acids, rho1V43T and rho1F44Y, showed a similar behavior, although some budding and actin polarization occurred at the nonpermissive temperature. This was also the case for rho1E45I when placed in a different genetic background. Cdc42p and Spa2p, two proteins that normally also move to the bud site in a process independent from actin organization, failed to localize properly in rho1E45I. Nuclear division did not occur in the mutant at 37°C, although replication of DNA proceeded slowly. The rho1 mutants were also defective in the formation of mating projections and in congregation of actin at the projections in the presence of mating pheromone. The in vitro activity of β(1→3)glucan synthase in rho1 E45I, although diminished at 37°C, appeared sufficient for normal in vivo function and the budding defect was not suppressed by expression of a constitutively active allele of PKC1. Reciprocally, when Pkc1p function was eliminated by the use of a temperature-sensitive mutation and β(1→3)glucan synthesis abolished by an echinocandin-like inhibitor, a strain carrying a wild-type RHO1 allele was able to produce incipient buds. Taken together, these results reveal a novel function of Rho1p that must be executed in order for the yeast cell to polarize.


2017 ◽  
Author(s):  
Shixuan Liu ◽  
Miriam B. Ginzberg ◽  
Nish Patel ◽  
Marc Hild ◽  
Bosco Leung ◽  
...  

AbstractAnimal cells within a tissue typically display a striking regularity in their size. To date, the molecular mechanisms that control this uniformity are still unknown. We have previously shown that size uniformity in animal cells is promoted, in part, by size-dependent regulation of G1 length. To identify the molecular mechanisms underlying this process, we performed a large-scale small molecule screen and found that the p38 MAPK pathway is involved in coordinating cell size and cell cycle progression. Small cells display higher p38 activity and spend more time in G1 than larger cells. Inhibition of p38 MAPK leads to loss of the compensatory G1 length extension in small cells, resulting in faster proliferation, smaller cell size and increased size heterogeneity. We propose a model wherein the p38 pathway responds to changes in cell size and regulates G1 exit accordingly, to increase cell size uniformity.One-sentence summaryThe p38 MAP kinase pathway coordinates cell growth and cell cycle progression by lengthening G1 in small cells, allowing them more time to grow before their next division.


2006 ◽  
Vol 17 (11) ◽  
pp. 4736-4747 ◽  
Author(s):  
Lisa Yu ◽  
Lourdes Peña Castillo ◽  
Sanie Mnaimneh ◽  
Timothy R. Hughes ◽  
Grant W. Brown

Mutations impacting specific stages of cell growth and division have provided a foundation for dissecting mechanisms that underlie cell cycle progression. We have undertaken an objective examination of the yeast cell cycle through flow cytometric analysis of DNA content in TetO7promoter mutant strains representing 75% of all essential yeast genes. More than 65% of the strains displayed specific alterations in DNA content, suggesting that reduced function of an essential gene in most cases impairs progression through a specific stage of the cell cycle. Because of the large number of essential genes required for protein biosynthesis, G1 accumulation was the most common phenotype observed in our analysis. In contrast, relatively few mutants displayed S-phase delay, and most of these were defective in genes required for DNA replication or nucleotide metabolism. G2 accumulation appeared to arise from a variety of defects. In addition to providing a global view of the diversity of essential cellular processes that influence cell cycle progression, these data also provided predictions regarding the functions of individual genes: we identified four new genes involved in protein trafficking (NUS1, PHS1, PGA2, PGA3), and we found that CSE1 and SMC4 are important for DNA replication.


2016 ◽  
Author(s):  
Daniel Dominguez ◽  
Yi-Hsuan Tsai ◽  
Robert Weatheritt ◽  
Yang Wang ◽  
Benjamin J Blencowe ◽  
...  

1998 ◽  
Vol 180 (15) ◽  
pp. 3864-3872 ◽  
Author(s):  
Lilia Alberghina ◽  
Carla Smeraldi ◽  
Bianca Maria Ranzi ◽  
Danilo Porro

ABSTRACT To gain insight on the interrelationships of the cellular environment, the properties of growth, and cell cycle progression, we analyzed the dynamic reactions of individual Saccharomyces cerevisiae cells to changes and manipulations of their surroundings. We used a new flow cytometric approach which allows, in asynchronous growing S. cerevisiae populations, tagging of both the cell age and the cell protein content of cells belonging to the different cell cycle set points. Since the cell protein content is a good estimation of the cell size, it is possible to follow the kinetics of the cell size increase during cell cycle progression. The analysis of the findings obtained indicates that both during a nutritional shift-up (from ethanol to glucose) and following the addition of cyclic AMP (cAMP), two important delays are induced. The preexisting cells that at the moment of the nutritional shift-up were cycling before the Start phase delay their entrance into S phase, while cells that were cycling after Start are delayed in their exit from the cycle. The combined effects of the two delays allow the cellular population that preexisted the shift-up to quickly adjust to the new growth condition. The effects of a nutritional shift-down were also determined.


2005 ◽  
Vol 274 (2) ◽  
Author(s):  
I. Donoso ◽  
M. C. Muñoz-Centeno ◽  
M. A. Sànchez-Durán ◽  
A. Flores ◽  
R. R. Daga ◽  
...  

2004 ◽  
Vol 24 (24) ◽  
pp. 10802-10813 ◽  
Author(s):  
Brandt L. Schneider ◽  
Jian Zhang ◽  
J. Markwardt ◽  
George Tokiwa ◽  
Tom Volpe ◽  
...  

ABSTRACT In Saccharomyces cerevisiae, commitment to cell cycle progression occurs at Start. Progression past Start requires cell growth and protein synthesis, a minimum cell size, and G1-phase cyclins. We examined the relationships among these factors. Rapidly growing cells expressed, and required, dramatically more Cln protein than did slowly growing cells. To clarify the role of cell size, we expressed defined amounts of CLN mRNA in cells of different sizes. When Cln was expressed at nearly physiological levels, a critical threshold of Cln expression was required for cell cycle progression, and this critical threshold varied with both cell size and growth rate: as cells grew larger, they needed less CLN mRNA, but as cells grew faster, they needed more Cln protein. At least in part, large cells had a reduced requirement for CLN mRNA because large cells generated more Cln protein per unit of mRNA than did small cells. When Cln was overexpressed, it was capable of promoting Start rapidly, regardless of cell size or growth rate. In summary, the amount of Cln required for Start depends dramatically on both cell size and growth rate. Large cells generate more Cln1 or Cln2 protein for a given amount of CLN mRNA, suggesting the existence of a novel posttranscriptional size control mechanism.


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