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19 results on '"Malcova, Ivana"'

10. Microbial Cell / Formaldehyde fixation is detrimental to actin cables in glucose-depleted S. cerevisiae cells

Author

Vasicova, Pavla, Rinnerthaler, Mark, Haskova, Danusa, Novakova, Lenka, Malcova, Ivana, Breitenbach, Michael, and Hasek, Jiri

Subjects
Actin patches, Abp140-GFP, macromolecular substances, yeast, Actin cables, Abp1-RFP
Abstract

Actin filaments form cortical patches and emanating cables in fermenting cells of Saccharomyces cerevisiae. This pattern has been shown to be depolarized in glucose-depleted cells after formaldehyde fixation and staining with rhodamine-tagged phalloidin. Loss of actin cables in mother cells was remarkable. Here we extend our knowledge on actin in live glucose-depleted cells co-expressing the marker of actin patches (Abp1-RFP) with the marker of actin cables (Abp140-GFP). Glucose depletion resulted in appearance of actin patches also in mother cells. However, even after 80 min of glucose deprivation these cells showed a clear network of actin cables labeled with Abp140-GFP in contrast to previously published data. In live cells with a mitochondrial dysfunction (rho0 cells), glucose depletion resulted in almost immediate appearance of Abp140-GFP foci partially overlapping with Abp1-RFP patches in mother cells. Residual actin cables were clustered in patch-associated bundles. A similar overlapping “patchy” pattern of both actin markers was observed upon treatment of glucose-deprived rho+ cells with FCCP (the inhibitor of oxidative phosphorylation) and upon treatment with formaldehyde. While the formaldehyde-targeted process stays unknown, our results indicate that published data on yeast actin cytoskeleton obtained from glucose-depleted cells after fixation should be considered with caution. P26713 (VLID)2689913

Published
2016

17. Heat Shock-Induced Accumulation of Translation Elongation and Termination Factors Precedes Assembly of Stress Granules in S. cerevisiae.

Author

Grousl, Tomas, Ivanov, Pavel, Malcova, Ivana, Pompach, Petr, Frydlova, Ivana, Slaba, Renata, Senohrabkova, Lenka, Novakova, Lenka, and Hasek, Jiri

Subjects
HEAT shock proteins, EUKARYOTIC cells, MESSENGER RNA, MOLECULAR self-assembly, CELL physiology, PROTEIN structure, MOLECULAR biology, CYTOPLASM
Abstract

In response to severe environmental stresses eukaryotic cells shut down translation and accumulate components of the translational machinery in stress granules (SGs). Since they contain mainly mRNA, translation initiation factors and 40S ribosomal subunits, they have been referred to as dominant accumulations of stalled translation preinitiation complexes. Here we present evidence that the robust heat shock-induced SGs of S. cerevisiae also contain translation elongation factors eEF3 (Yef3p) and eEF1Bγ2 (Tef4p) as well as translation termination factors eRF1 (Sup45p) and eRF3 (Sup35p). Despite the presence of the yeast prion protein Sup35 in heat shock-induced SGs, we found out that its prion-like domain is not involved in the SGs assembly. Factors eEF3, eEF1Bγ2 and eRF1 were accumulated and co-localized with Dcp2 foci even upon a milder heat shock at 42°C independently of P-bodies scaffolding proteins. We also show that eEF3 accumulations at 42°C determine sites of the genuine SGs assembly at 46°C. We suggest that identification of translation elongation and termination factors in SGs might help to understand the mechanism of the eIF2α factor phosphorylation-independent repression of translation and SGs assembly. [ABSTRACT FROM AUTHOR]

Published
2013
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18. Deregulation of DSE1Gene Expression Results in Aberrant Budding within the Birth Scar and Cell Wall Integrity Pathway Activation in Saccharomyces cerevisiae

Author

Fry´dlova´, Ivana, Malcova´, Ivana, Vas?icova´, Pavla, and Has?ek, Jir?i´

Abstract

ABSTRACTStrains of Saccharomyces cerevisiaelacking Isw2, the catalytic subunit of the Isw2 chromatin remodeling complex, show the mating type-independent activation of the cell wall integrity (CWI) signaling pathway. Since the CWI pathway activation usually reflects cell wall defects, we searched for the cell wall-related genes changed in expression. The genes DSE1, CTS1, and CHS1were upregulated as a result of the absence of Isw2, according to previously published gene expression profiles (I. Frydlova, M. Basler, P. Vasicova, I. Malcova, and J. Hasek, Curr. Genet. 52:87-95, 2007). Western blot analyses of double deletion mutants, however, did not indicate the contribution of the chitin metabolism-related genes CTS1and CHS1to the CWI pathway activation. Nevertheless, the deletion of the DSE1gene encoding a daughter cell-specific protein with unknown function suppressed CWI pathway activation in isw2? cells. In addition, the deletion of DSE1also abolished the budding-within-the-birth-scar phenotype of isw2? cells. The plasmid-driven overexpression proved that the deregulation of Dse1 synthesis was also responsible for CWI pathway activation and manifestation of the budding-within-the-birth-scar phenotype in wild-type cells. The overproduced Dse1-green fluorescent protein localized to both sides of the septum and persisted in unbudded cells. Although the exact cellular role of this daughter cell-specific protein has to be elucidated, our data point to the involvement of Dse1 in bud site selection in haploid cells.

Published
2009
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19. Heat Shock-Induced Accumulation of Translation Elongation and Termination Factors Precedes Assembly of Stress Granules in S. cerevisiae.

Author

Grousl, Tomas, Ivanov, Pavel, Malcova, Ivana, Pompach, Petr, Frydlova, Ivana, Slaba, Renata, Senohrabkova, Lenka, Novakova, Lenka, and Hasek, Jiri

Subjects
*HEAT shock proteins, *EUKARYOTIC cells, *MESSENGER RNA, *MOLECULAR self-assembly, *CELL physiology, *PROTEIN structure, *MOLECULAR biology, *CYTOPLASM
Abstract

In response to severe environmental stresses eukaryotic cells shut down translation and accumulate components of the translational machinery in stress granules (SGs). Since they contain mainly mRNA, translation initiation factors and 40S ribosomal subunits, they have been referred to as dominant accumulations of stalled translation preinitiation complexes. Here we present evidence that the robust heat shock-induced SGs of S. cerevisiae also contain translation elongation factors eEF3 (Yef3p) and eEF1Bγ2 (Tef4p) as well as translation termination factors eRF1 (Sup45p) and eRF3 (Sup35p). Despite the presence of the yeast prion protein Sup35 in heat shock-induced SGs, we found out that its prion-like domain is not involved in the SGs assembly. Factors eEF3, eEF1Bγ2 and eRF1 were accumulated and co-localized with Dcp2 foci even upon a milder heat shock at 42°C independently of P-bodies scaffolding proteins. We also show that eEF3 accumulations at 42°C determine sites of the genuine SGs assembly at 46°C. We suggest that identification of translation elongation and termination factors in SGs might help to understand the mechanism of the eIF2α factor phosphorylation-independent repression of translation and SGs assembly. [ABSTRACT FROM AUTHOR]

Published
2013
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