Balanced activities of Hsp70 and the ubiquitin proteasome system underlie cellular protein homeostasis

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61388971%3A_____%2F23%3A00579770" target="_blank" >RIV/61388971:_____/23:00579770 - isvavai.cz</a>

Výsledek na webu

<a href="https://www.frontiersin.org/articles/10.3389/fmolb.2022.1106477/full" target="_blank" >https://www.frontiersin.org/articles/10.3389/fmolb.2022.1106477/full</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.3389/fmolb.2022.1106477" target="_blank" >10.3389/fmolb.2022.1106477</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Balanced activities of Hsp70 and the ubiquitin proteasome system underlie cellular protein homeostasis

Popis výsledku v původním jazyce

To counteract proteotoxic stress and cellular aging, protein quality control (PQC) systems rely on the refolding, degradation and sequestration of misfolded proteins. In Saccharomyces cerevisiae the Hsp70 chaperone system plays a central role in protein refolding, while degradation is predominantly executed by the ubiquitin proteasome system (UPS). The sequestrases Hsp42 and Btn2 deposit misfolded proteins in cytosolic and nuclear inclusions, thereby restricting the accessibility of misfolded proteins to Hsp70 and preventing the exhaustion of limited Hsp70 resources. Therefore, in yeast, sequestrase mutants show negative genetic interactions with double mutants lacking the Hsp70 co-chaperone Fes1 and the Hsp104 disaggregase (fes1 delta hsp104 delta, delta delta) and suffering from low Hsp70 capacity. Growth of delta delta btn2 delta mutants is highly temperature-sensitive and results in proteostasis breakdown at non-permissive temperatures. Here, we probed for the role of the ubiquitin proteasome system in maintaining protein homeostasis in delta delta btn2 delta cells, which are affected in two major protein quality control branches. We show that delta delta btn2 delta cells induce expression of diverse stress related pathways including the ubiquitin proteasome system to counteract the proteostasis defects. Ubiquitin proteasome system dependent degradation of the stringent Hsp70 substrate firefly Luciferase in the mutant cells mirrors such compensatory activities of the protein quality control system. Surprisingly however, the enhanced ubiquitin proteasome system activity does not improve but aggravates the growth defects of ddbtn2d cells. Reducing ubiquitin proteasome system activity in the mutant by lowering the levels of functional 26S proteasomes improved growth, increased refolding yield of the Luciferase reporter and attenuated global stress responses. Our findings indicate that an imbalance between Hsp70-dependent refolding, sequestration and ubiquitin proteasome system-mediated degradation activities strongly affects protein homeostasis of Hsp70 capacity mutants and contributes to their severe growth phenotypes.

Název v anglickém jazyce

Balanced activities of Hsp70 and the ubiquitin proteasome system underlie cellular protein homeostasis

Popis výsledku anglicky

To counteract proteotoxic stress and cellular aging, protein quality control (PQC) systems rely on the refolding, degradation and sequestration of misfolded proteins. In Saccharomyces cerevisiae the Hsp70 chaperone system plays a central role in protein refolding, while degradation is predominantly executed by the ubiquitin proteasome system (UPS). The sequestrases Hsp42 and Btn2 deposit misfolded proteins in cytosolic and nuclear inclusions, thereby restricting the accessibility of misfolded proteins to Hsp70 and preventing the exhaustion of limited Hsp70 resources. Therefore, in yeast, sequestrase mutants show negative genetic interactions with double mutants lacking the Hsp70 co-chaperone Fes1 and the Hsp104 disaggregase (fes1 delta hsp104 delta, delta delta) and suffering from low Hsp70 capacity. Growth of delta delta btn2 delta mutants is highly temperature-sensitive and results in proteostasis breakdown at non-permissive temperatures. Here, we probed for the role of the ubiquitin proteasome system in maintaining protein homeostasis in delta delta btn2 delta cells, which are affected in two major protein quality control branches. We show that delta delta btn2 delta cells induce expression of diverse stress related pathways including the ubiquitin proteasome system to counteract the proteostasis defects. Ubiquitin proteasome system dependent degradation of the stringent Hsp70 substrate firefly Luciferase in the mutant cells mirrors such compensatory activities of the protein quality control system. Surprisingly however, the enhanced ubiquitin proteasome system activity does not improve but aggravates the growth defects of ddbtn2d cells. Reducing ubiquitin proteasome system activity in the mutant by lowering the levels of functional 26S proteasomes improved growth, increased refolding yield of the Luciferase reporter and attenuated global stress responses. Our findings indicate that an imbalance between Hsp70-dependent refolding, sequestration and ubiquitin proteasome system-mediated degradation activities strongly affects protein homeostasis of Hsp70 capacity mutants and contributes to their severe growth phenotypes.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10606 - Microbiology

Projekt

—

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2023

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Frontiers in molecular biosciences

ISSN

2296-889X

e-ISSN

2296-889X

Svazek periodika

9

Číslo periodika v rámci svazku

4 January 2023

Stát vydavatele periodika

CH - Švýcarská konfederace

Počet stran výsledku

14

Strana od-do

1106477

Kód UT WoS článku

000950629900001

EID výsledku v databázi Scopus

2-s2.0-85146469891