Essentiality of Sis1, a J-domain protein Hsp70 cochaperone, can be overcome by Tti1, a specialized PIKK chaperone

2021 ◽  
Author(s):  
Brenda A. Schilke ◽  
Elizabeth A. Craig
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Heat Shock ◽  
Essential Gene ◽  
Specific Inhibitor ◽  
The Other ◽  
Phosphatidylinositol 3 Kinase ◽  
Complex Cells ◽  
J Domain ◽  
Domain Protein ◽  
Transcription Factor 1

J-domain protein cochaperones drive much of the functional diversity of Hsp70-based chaperone systems. Sis1 is the only essential J-domain protein of the cytosol/nucleus of Saccharomyces cerevisiae. Why it is required for cell growth is not understood, nor is how critical its role in regulation of heat shock transcription factor 1 (Hsf1). We report that single residue substitutions in Tti1, a component of the heterotrimeric TTT complex, a specialized chaperone system for phosphatidylinositol 3-kinase-related kinase (PIKK) proteins, allow growth of cells lacking Sis1. Upon depletion of Sis1, cells become hypersensitive to rapamycin, a specific inhibitor of TORC1 kinase. In addition, levels of the three essential PIKKs (Mec1, Tra1, and Tor2), as well as Tor1, decrease upon Sis1depletion. Overexpression of Tti1 allows growth, without an increase in the other subunits of the TTT complex, Tel2 and Tti2, suggesting that it can function independent of the complex. Cells lacking Sis1, with viability supported by Tti1 suppressor, substantially upregulate some, but not all, heat shock elements activated by Hsf1. Together, our results suggest that Sis1 is required as a cochaperone of Hsp70 for the folding/maintenance of PIKKs making Sis1 an essential gene, and its requirement for Hsf1 regulation is more nuanced than generally appreciated.

Correlation between the activity of a 5,6-dichloro-1-β-D-ribofuranosylbenzimidazole-insensitive puff and the synthesis of major heat-shock polypeptide, hsp70, in Chironomus thummi

1988 ◽  
Vol 66 (11) ◽  
pp. 1177-1185 ◽  
Author(s):  
D. Barettino ◽  
G. Morcillo ◽  
J. L. Díez ◽  
M. T. Carretero ◽  
M. J. Carmona
Keyword(s):  
Heat Shock ◽  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Specific Inhibitor ◽  
In Vitro Transcription ◽  
The Other ◽  
Low Salt ◽  
Transcription Inhibitor ◽  
Chironomus Thummi

The induction of puff III-A3b, a major heat-shock puff in Chironomus thummi salivary cells, was insensitive to the transcription inhibitor 5,6-dichloro-1-β-D-ribofuranosylbenzimidazole (DRB), whereas no transcriptional activity could be detected at the other heat-shock puffs in the presence of this drug. In these conditions, a polypeptide with the same Mr and isoform pattern as those of the major heat-shock polypeptide, hsp70, was synthesized. These results suggest that hsp70 is encoded by locus III-A3b. In addition to DRB insensitivity, incorporation of [3H]UTP on puff III-A3b took place in an in vitro transcription assay under low-salt conditions (100 mM NaCl); no labelling could be detected at the other heat-shock puffs under these conditions. Although DRB has been reported as a specific inhibitor of RNA polymerase II-directed transcription, and although the low-salt conditions were not propitious for the activity of this enzyme, RNA polymerase II was detected on puff III-A3b and on the other heat-shock puffs by immunofluorescence with anti-RNA polymerase II antibodies.

The two gene pairs encoding H2A and H2B play different roles in the Saccharomyces cerevisiae life cycle

1987 ◽  
Vol 7 (10) ◽  
pp. 3473-3481
Author(s):  
D Norris ◽  
M A Osley
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Life Cycle ◽  
Heat Shock ◽  
Heat Shock Response ◽  
Spore Germination ◽  
Gene Pair ◽  
The Other ◽  
Gene Pairs ◽  
Gene Sets ◽  
Shock Response

We have isolated Saccharomyces cerevisiae mutants bearing deletions of one or the other of the two divergently transcribed gene pairs encoding H2A and H2B. The deletions produced diverse effects on the yeast life cycle. Deletion of TRT1, one of the H2A-H2B gene pair sets, affected mitotic growth, sporulation, spore germination, the heat shock response, and exit from the stationary phase; deletion of TRT2, the other H2A-H2B gene pair set, had negligible effects on these same processes. Using a genetic complementation assay, we found that the differential effects of the deletions could be attributed to two features of the gene sets: first, the expression of the TRT1 gene pair, but not the TRT2 gene pair, could compensate for the absence of its partner; second, the protein subtypes encoded by the two gene pairs appear to have different functions in the heat shock response.

scholarly journals A Bacteriophage-Encoded J-Domain Protein Interacts with the DnaK/Hsp70 Chaperone and Stabilizes the Heat-Shock Factor σ32 of Escherichia coli

PLoS Genetics ◽  
2012 ◽  
Vol 8 (11) ◽  
pp. e1003037 ◽  
Author(s):  
Elsa Perrody ◽  
Anne-Marie Cirinesi ◽  
Carine Desplats ◽  
France Keppel ◽  
Françoise Schwager ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Heat Shock ◽  
Heat Shock Factor ◽  
Hsp70 Chaperone ◽  
J Domain ◽  
Domain Protein

scholarly journals The two gene pairs encoding H2A and H2B play different roles in the Saccharomyces cerevisiae life cycle.

1987 ◽  
Vol 7 (10) ◽  
pp. 3473-3481 ◽  
Author(s):  
D Norris ◽  
M A Osley
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Life Cycle ◽  
Heat Shock ◽  
Heat Shock Response ◽  
Spore Germination ◽  
Gene Pair ◽  
The Other ◽  
Gene Pairs ◽  
Gene Sets ◽  
Shock Response

We have isolated Saccharomyces cerevisiae mutants bearing deletions of one or the other of the two divergently transcribed gene pairs encoding H2A and H2B. The deletions produced diverse effects on the yeast life cycle. Deletion of TRT1, one of the H2A-H2B gene pair sets, affected mitotic growth, sporulation, spore germination, the heat shock response, and exit from the stationary phase; deletion of TRT2, the other H2A-H2B gene pair set, had negligible effects on these same processes. Using a genetic complementation assay, we found that the differential effects of the deletions could be attributed to two features of the gene sets: first, the expression of the TRT1 gene pair, but not the TRT2 gene pair, could compensate for the absence of its partner; second, the protein subtypes encoded by the two gene pairs appear to have different functions in the heat shock response.

scholarly journals The Heat Shock Protein Ssa2p Is Required for Import of Fructose-1,6-Bisphosphatase into Vid Vesicles

2000 ◽  
Vol 150 (1) ◽  
pp. 65-76 ◽  
Author(s):  
C. Randell Brown ◽  
Jameson A. McCann ◽  
Hui-Ling Chiang
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Heat Shock ◽  
Heat Shock Protein ◽  
Binding Proteins ◽  
The Other ◽  
Atp Binding ◽  
Wild Type ◽  
Fructose 1,6 Bisphosphatase

Fructose-1,6-bisphosphatase (FBPase) is targeted to the vacuole for degradation when Saccharomyces cerevisiae are shifted from low to high glucose. Before vacuolar import, however, FBPase is sequestered inside a novel type of vesicle, the vacuole import and degradation (Vid) vesicles. Here, we reconstitute import of FBPase into isolated Vid vesicles. FBPase sequestration into Vid vesicles required ATP and cytosol, but was inhibited if ATP binding proteins were depleted from the cytosol. The heat shock protein Ssa2p was identified as one of the ATP binding proteins involved in FBPase import. A Δssa2 strain exhibited a significant decrease in the rate of FBPase degradation in vivo as compared with Δssa1, Δssa3, or Δssa4 strains. Likewise, in vitro import was impaired for the Δssa2 strain, but not for the other Δssa strains. The cytosol was identified as the site of the Δssa2 defect; Δssa2 cytosol did not stimulate FBPase import into import competent Vid vesicles, but wild-type cytosol supported FBPase import into competent Δssa2 vesicles. The addition of purified recombinant Ssa2p stimulated FBPase import into Δssa2 Vid vesicles, providing Δssa2 cytosol was present. Thus, Ssa2p, as well as other undefined cytosolic proteins are required for the import of FBPase into vesicles.

scholarly journals The glycosylation of phosphoglucomutase is modulated by carbon source and heat shock in Saccharomyces cerevisiae.

1994 ◽  
Vol 269 (43) ◽  
pp. 27143-27148
Author(s):  
N B Dey ◽  
P Bounelis ◽  
T A Fritz ◽  
D M Bedwell ◽  
R B Marchase
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Heat Shock ◽  
Carbon Source

scholarly journals Recombination of Ty elements in yeast can be induced by a double-strand break.

Genetics ◽  
1995 ◽  
Vol 140 (1) ◽  
pp. 67-77 ◽  
Author(s):  
A Parket ◽  
O Inbar ◽  
M Kupiec
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Strand Break ◽  
Double Strand Break ◽  
The Other ◽  
Direct Repeats ◽  
Yeast Saccharomyces Cerevisiae ◽  
Low Frequencies ◽  
Ty Elements ◽  
Main Family

Abstract The Ty retrotransposons are the main family of dispersed repeated sequences in the yeast Saccharomyces cerevisiae. These elements are flanked by a pair of long terminal direct repeats (LTRs). Previous experiments have shown that Ty elements recombine at low frequencies, despite the fact that they are present in 30 copies per genome. This frequency is not highly increased by treatments that cause DNA damage, such as UV irradiation. In this study, we show that it is possible to increase the recombination level of a genetically marked Ty by creating a double-strand break in it. This break is repaired by two competing mechanisms: one of them leaves a single LTR in place of the Ty, and the other is a gene conversion event in which the marked Ty is replaced by an ectopically located one. In a strain in which the marked Ty has only one LTR, the double-strand break is repaired by conversion. We have also measured the efficiency of repair and monitored the progression of the cells through the cell-cycle. We found that in the presence of a double-strand break in the marked Ty, a proportion of the cells is unable to resume growth.

scholarly journals The PBN1 Gene of Saccharomyces cerevisiae: An Essential Gene That Is Required for the Post-translational Processing of the Protease B Precursor

Genetics ◽  
1998 ◽  
Vol 149 (3) ◽  
pp. 1277-1292 ◽  
Author(s):  
Rajesh R Naik ◽  
Elizabeth W Jones
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Secretory Pathway ◽  
Transmembrane Domain ◽  
Essential Gene ◽  
Signal Sequence ◽  
Signal Peptidase ◽  
Amino Terminal ◽  
Autocatalytic Cleavage ◽  
Protease B ◽  
Chromosome Iii

Abstract The vacuolar hydrolase protease B in Saccharomyces cerevisiae is synthesized as an inactive precursor (Prb1p). The precursor undergoes post-translational modifications while transiting the secretory pathway. In addition to N- and O -linked glycosylations, four proteolytic cleavages occur during the maturation of Prb1p. Removal of the signal peptide by signal peptidase and the autocatalytic cleavage of the large aminoterminal propeptide occur in the endoplasmic reticulum (ER). Two carboxy-terminal cleavages of the post regions occur in the vacuole: the first cleavage is catalyzed by protease A and the second results from autocatalysis. We have isolated a mutant, pbn1-1, that exhibits a defect in the ER processing of Prb1p. The autocatalytic cleavage of the propeptide from Prb1p does not occur and Prb1p is rapidly degraded in the cytosol. PBN1 was cloned and is identical to YCL052c on chromosome III. PBN1 is an essential gene that encodes a novel protein. Pbn1p is predicted to contain a sub-C-terminal transmembrane domain but no signal sequence. A functional HA epitope-tagged Pbn1p fusion localizes to the ER. Pbn1p is N-glycosylated in its amino-terminal domain, indicating a lumenal orientation despite the lack of a signal sequence. Based on these results, we propose that one of the functions of Pbn1p is to aid in the autocatalytic processing of Prb1p.

Sign in / Sign up

Export Citation Format

Share Document