scholarly journals Polymerization in the actin ATPase clan regulates hexokinase activity in yeast

Science ◽  
2020 ◽  
Vol 367 (6481) ◽  
pp. 1039-1042 ◽  
Author(s):  
Patrick R. Stoddard ◽  
Eric M. Lynch ◽  
Daniel P. Farrell ◽  
Annie M. Dosey ◽  
Frank DiMaio ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Enzymatic Activity ◽  
Enzyme Inhibition ◽  
Nutrient Availability ◽  
Maximum Rate ◽  
Metabolic Enzymes ◽  
Hexokinase Activity ◽  
Sugar Addition ◽  
Glucose Phosphorylation ◽  
In Cells

The actin fold is found in cytoskeletal polymers, chaperones, and various metabolic enzymes. Many actin-fold proteins, such as the carbohydrate kinases, do not polymerize. We found that Glk1, a Saccharomyces cerevisiae glucokinase, forms two-stranded filaments with ultrastructure that is distinct from that of cytoskeletal polymers. In cells, Glk1 polymerized upon sugar addition and depolymerized upon sugar withdrawal. Polymerization inhibits enzymatic activity; the Glk1 monomer-polymer equilibrium sets a maximum rate of glucose phosphorylation regardless of Glk1 concentration. A mutation that eliminated Glk1 polymerization alleviated concentration-dependent enzyme inhibition. Yeast containing nonpolymerizing Glk1 were less fit when growing on sugars and more likely to die when refed glucose. Glk1 polymerization arose independently from other actin-related filaments and may allow yeast to rapidly modulate glucokinase activity as nutrient availability changes.

scholarly journals Independent evolution of polymerization in the Actin ATPase clan regulates hexokinase activity

2019 ◽  
Author(s):  
Patrick R Stoddard ◽  
Eric M. Lynch ◽  
Daniel P. Farrell ◽  
Quincey A. Justman ◽  
Annie M. Dosey ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Enzymatic Activity ◽  
Maximum Rate ◽  
Protein Fold ◽  
Hexokinase Activity ◽  
Sugar Addition ◽  
Glucose Phosphorylation ◽  
Ascomycete Fungi ◽  
Actin Protein

AbstractThe actin protein fold is found in cytoskeletal polymers, chaperones, and various metabolic enzymes. Many actin-fold proteins, like the carbohydrate kinases, do not polymerize. We find that Glk1, aSaccharomyces cerevisiaeglucokinase, forms two-stranded filaments with unique ultrastructure, distinct from that of cytoskeletal polymers. In cells, Glk1 polymerizes upon sugar addition and depolymerizes upon sugar withdrawal. Glk1 polymerization inhibits its enzymatic activity, thus the Glk1 monomer-polymer equilibrium sets a maximum rate of glucose phosphorylation regardless of Glk1 concentration. A mutation eliminating Glk1 polymerization alleviates concentration-dependent enzyme inhibition, causing glucokinase activity to become unconstrained. Polymerization-based regulation of Glk1 activity serves an important functionin vivo: yeast containing non-polymerizing Glk1 are less fit when growing on sugars and more likely to die when refed glucose. Glucokinase polymerization arose within the ascomycete fungi and is conserved across a group of divergent (150-200 mya) yeast. We show that Glk1 polymerization arose independently from other actin-related filaments and allows yeast to rapidly modulate glucokinase activity as nutrient availability changes.One-sentence summaryYeast glucokinase activity is limited by its polymerization, which is critical for cell viability during glucose refeeding.

scholarly journals Effects of Temperature on the Meiotic Recombination Landscape of the Yeast Saccharomyces cerevisiae

mBio ◽  
2017 ◽  
Vol 8 (6) ◽  
Author(s):  
Ke Zhang ◽  
Xue-Chang Wu ◽  
Dao-Qiong Zheng ◽  
Thomas D. Petes
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Gene Conversion ◽  
Meiotic Recombination ◽  
Hot Spots ◽  
Genetic Maps ◽  
Dna Breaks ◽  
Low Levels ◽  
C 30 ◽  
Recombination Hot Spots ◽  
In Cells

ABSTRACT Although meiosis in warm-blooded organisms takes place in a narrow temperature range, meiosis in many organisms occurs over a wide variety of temperatures. We analyzed the properties of meiosis in the yeast Saccharomyces cerevisiae in cells sporulated at 14°C, 30°C, or 37°C. Using comparative-genomic-hybridization microarrays, we examined the distribution of Spo11-generated meiosis-specific double-stranded DNA breaks throughout the genome. Although there were between 300 and 400 regions of the genome with high levels of recombination (hot spots) observed at each temperature, only about 20% of these hot spots were found to have occurred independently of the temperature. In S. cerevisiae , regions near the telomeres and centromeres tend to have low levels of meiotic recombination. This tendency was observed in cells sporulated at 14°C and 30°C, but not at 37°C. Thus, the temperature of sporulation in yeast affects some global property of chromosome structure relevant to meiotic recombination. Using single-nucleotide polymorphism (SNP)-specific whole-genome microarrays, we also examined crossovers and their associated gene conversion events as well as gene conversion events that were unassociated with crossovers in all four spores of tetrads obtained by sporulation of diploids at 14°C, 30°C, or 37°C. Although tetrads from cells sporulated at 30°C had slightly (20%) more crossovers than those derived from cells sporulated at the other two temperatures, spore viability was good at all three temperatures. Thus, despite temperature-induced variation in the genetic maps, yeast cells produce viable haploid products at a wide variety of sporulation temperatures. IMPORTANCE In the yeast Saccharomyces cerevisiae , recombination is usually studied in cells that undergo meiosis at 25°C or 30°C. In a genome-wide analysis, we showed that the locations of genomic regions with high and low levels of meiotic recombination (hot spots and cold spots, respectively) differed dramatically in cells sporulated at 14°C, 30°C, and 37°C. Thus, in yeast, and likely in other non-warm-blooded organisms, genetic maps are strongly affected by the environment.

scholarly journals UVA radiation is highly mutagenic in cells that are unable to repair 7,8-dihydro-8-oxoguanine in Saccharomyces cerevisiae

2005 ◽  
Vol 102 (38) ◽  
pp. 13538-13543 ◽  
Author(s):  
S. Kozmin ◽  
G. Slezak ◽  
A. Reynaud-Angelin ◽  
C. Elie ◽  
Y. de Rycke ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Uva Radiation ◽  
In Cells

Evidence that POB1, a Saccharomyces cerevisiae protein that binds to DNA polymerase alpha, acts in DNA metabolism in vivo

1992 ◽  
Vol 12 (12) ◽  
pp. 5724-5735
Author(s):  
J Miles ◽  
T Formosa
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Dna Replication ◽  
Dna Polymerase ◽  
Yeast Cells ◽  
Chromosome Loss ◽  
Dna Metabolism ◽  
Checkpoint Gene ◽  
Dna Polymerase Alpha ◽  
In Cells

Potential DNA replication accessory factors from the yeast Saccharomyces cerevisiae have previously been identified by their ability to bind to DNA polymerase alpha protein affinity matrices (J. Miles and T. Formosa, Proc. Natl. Acad. Sci. USA 89:1276-1280, 1992). We have now used genetic methods to characterize the gene encoding one of these DNA polymerase alpha-binding proteins (POB1) to determine whether it plays a role in DNA replication in vivo. We find that yeast cells lacking POB1 are viable but display a constellation of phenotypes indicating defective DNA metabolism. Populations of cells lacking POB1 accumulate abnormally high numbers of enlarged large-budded cells with a single nucleus at the neck of the bud. The average DNA content in a population of cells lacking POB1 is shifted toward the G2 value. These two phenotypes indicate that while the bulk of DNA replication is completed without POB1, mitosis is delayed. Deleting POB1 also causes elevated levels of both chromosome loss and genetic recombination, enhances the temperature sensitivity of cells with mutant DNA polymerase alpha genes, causes increased sensitivity to UV radiation in cells lacking a functional RAD9 checkpoint gene, and causes an increased probability of death in cells carrying a mutation in the MEC1 checkpoint gene. The sequence of the POB1 gene indicates that it is identical to the CTF4 (CHL15) gene identified previously in screens for mutations that diminish the fidelity of chromosome transmission. These phenotypes are consistent with defective DNA metabolism in cells lacking POB1 and strongly suggest that this DNA polymerase alpha-binding protein plays a role in accurately duplicating the genome in vivo.

Cloning and molecular analysis of the HAP2 locus: a global regulator of respiratory genes in Saccharomyces cerevisiae

1985 ◽  
Vol 5 (12) ◽  
pp. 3410-3416
Author(s):  
J L Pinkham ◽  
L Guarente
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Molecular Analysis ◽  
Carbon Sources ◽  
Direct Integration ◽  
Global Regulator ◽  
Low Levels ◽  
Gene Maps ◽  
Derivatives Of ◽  
In Cells

We report here the cloning of the HAP2 gene, a locus required for the expression of many cytochromes and respiratory functions in Saccharomyces cerevisiae. The cloned sequences were found to direct integration of a marked vector to the chromosomal HAP2 locus, and derivatives of these sequences were shown to yield chromosomal disruptions with a Hap2- phenotype. The gene maps 18 centimorgans centromere proximal to ade5 on the left arm of chromosome VII, distinguishing it from any other previously characterized nuclear petite locus. The HAP2 locus encodes a 1.3-kilobase transcript which is present at extremely low levels and which is derepressed in cells grown in media containing nonfermentable carbon sources. Levels of HAP2 mRNA are not reduced in strains bearing a mutation at the HAP3 locus, which is also required for expression of respiratory functions. Models outlining possible interactions of the products of the HAP2 and HAP3 genes are presented.

The lethality of p60v-src in Saccharomyces cerevisiae and the activation of p34CDC28 kinase are dependent on the integrity of the SH2 domain

1993 ◽  
Vol 105 (2) ◽  
pp. 519-528
Author(s):  
F. Boschelli ◽  
S.M. Uptain ◽  
J.J. Lightbody
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Protein Tyrosine Kinase ◽  
Kinase Activity ◽  
Cell Cycle Control ◽  
Sh2 Domain ◽  
Wild Type ◽  
Type V ◽  
Cdc28 Kinase ◽  
In Cells

The lethal effects of the expression of the oncogenic protein tyrosine kinase p60v-src in Saccharomyces cerevisiae are associated with a loss of cell cycle control at the G1/S and G2/M checkpoints. Results described here indicate that the ability of v-Src to kill yeast is dependent on the integrity of the SH2 domain, a region of the Src protein involved in recognition of proteins phosphorylated on tyrosine. Catalytically active v-Src proteins with deletions in the SH2 domain have little effect on yeast growth, unlike wild-type v-Src protein, which causes accumulation of large-budded cells, perturbation of spindle microtubules and increased DNA content when expressed. The proteins phosphorylated on tyrosine in cells expressing v-Src differ from those in cells expressing a Src protein with a deletion in the SH2 domain. Also, unlike the wild-type v-Src protein, which drastically increases histone H1-associated Cdc28 kinase activity, c-Src and an altered v-Src protein have no effect on Cdc28 kinase activity. These results indicate that the SH2 domain is functionally important in the disruption of the yeast cell cycle by v-Src.

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