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Sch9 regulates intracellular protein ubiquitination by controlling stress responses.

Qie B, Lyu Z, Lyu L, Liu J, Gao X, Liu Y, Duan W, Zhang N, Du L, Liu K - Redox Biol (2015)

Bottom Line: In this study, we found that the overall level of ubiquitinated proteins dramatically decreased as yeast cell grew from log to stationary phase.Deletion of SCH9, a gene encoding a key protein kinase for longevity control, decreased the level of ubiquitinated proteins in log phase and this effect could be reversed by restoring Sch9 function.Our results revealed for the first time how Sch9 regulates the level of ubiquitinated proteins and provides new insight into how Sch9 controls longevity.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Bio-Resources and Eco-Environment of Ministry of Education, College of Life Science, Sichuan University, Chengdu, Sichuan 610064, China.

No MeSH data available.


The Regulation of Protein ubiquitination through Sch9 signaling during growth. A speculative model of how reduced Sch9 signaling down-regulated ubiquitinated proteins by Rim15-dependent stress-resistance pathways (left arm) and adaptive mitochondrial ROS signaling (right arm). Elevated respiration in sch9∆ cells is mediated by upregulation of the transcription factors Hap4 or Hcm1 which gives rise to increased respiration and intracellular superoxide during growth [32,33]. Superoxide may serve as an adaptive signal to activate stress response genes (horizontal arrow). Therefore, although elevated cellular superoxide leads to accumulated H2O2, enhanced stress Resistance via Rim15 pathway and adaptive superoxide signal [30], on the other hand, diminishes H2O2 more effectively (bold arrow). Elimination of H2O2 in sch9∆ cells in turn reduces the oxidation of intracellular proteins including those of newly synthesized and their subsequent ubiquitination.
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f0035: The Regulation of Protein ubiquitination through Sch9 signaling during growth. A speculative model of how reduced Sch9 signaling down-regulated ubiquitinated proteins by Rim15-dependent stress-resistance pathways (left arm) and adaptive mitochondrial ROS signaling (right arm). Elevated respiration in sch9∆ cells is mediated by upregulation of the transcription factors Hap4 or Hcm1 which gives rise to increased respiration and intracellular superoxide during growth [32,33]. Superoxide may serve as an adaptive signal to activate stress response genes (horizontal arrow). Therefore, although elevated cellular superoxide leads to accumulated H2O2, enhanced stress Resistance via Rim15 pathway and adaptive superoxide signal [30], on the other hand, diminishes H2O2 more effectively (bold arrow). Elimination of H2O2 in sch9∆ cells in turn reduces the oxidation of intracellular proteins including those of newly synthesized and their subsequent ubiquitination.

Mentions: Although the deletion of SCH9 enhances mitochondrial respiration by activating Hcm1 and probably Hap4 to promote the superoxide production [32,33], it may also stimulate the stress response via Rim15 and its downstream factors [30]. The increased level of superoxide may also enhance the oxidative resistance as an adaptive ROS signaling [11]. Together, the deletion of SCH9 causes the up-regulation of the intracellular antioxidants and the decrease of H2O2, which damages intracellular proteins and subsequently causes ubiquitination. The plausible mechanisms by which Sch9 regulates protein ubiquitination are summarized in Fig. 7.


Sch9 regulates intracellular protein ubiquitination by controlling stress responses.

Qie B, Lyu Z, Lyu L, Liu J, Gao X, Liu Y, Duan W, Zhang N, Du L, Liu K - Redox Biol (2015)

The Regulation of Protein ubiquitination through Sch9 signaling during growth. A speculative model of how reduced Sch9 signaling down-regulated ubiquitinated proteins by Rim15-dependent stress-resistance pathways (left arm) and adaptive mitochondrial ROS signaling (right arm). Elevated respiration in sch9∆ cells is mediated by upregulation of the transcription factors Hap4 or Hcm1 which gives rise to increased respiration and intracellular superoxide during growth [32,33]. Superoxide may serve as an adaptive signal to activate stress response genes (horizontal arrow). Therefore, although elevated cellular superoxide leads to accumulated H2O2, enhanced stress Resistance via Rim15 pathway and adaptive superoxide signal [30], on the other hand, diminishes H2O2 more effectively (bold arrow). Elimination of H2O2 in sch9∆ cells in turn reduces the oxidation of intracellular proteins including those of newly synthesized and their subsequent ubiquitination.
© Copyright Policy - CC BY-NC-ND
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4477112&req=5

f0035: The Regulation of Protein ubiquitination through Sch9 signaling during growth. A speculative model of how reduced Sch9 signaling down-regulated ubiquitinated proteins by Rim15-dependent stress-resistance pathways (left arm) and adaptive mitochondrial ROS signaling (right arm). Elevated respiration in sch9∆ cells is mediated by upregulation of the transcription factors Hap4 or Hcm1 which gives rise to increased respiration and intracellular superoxide during growth [32,33]. Superoxide may serve as an adaptive signal to activate stress response genes (horizontal arrow). Therefore, although elevated cellular superoxide leads to accumulated H2O2, enhanced stress Resistance via Rim15 pathway and adaptive superoxide signal [30], on the other hand, diminishes H2O2 more effectively (bold arrow). Elimination of H2O2 in sch9∆ cells in turn reduces the oxidation of intracellular proteins including those of newly synthesized and their subsequent ubiquitination.
Mentions: Although the deletion of SCH9 enhances mitochondrial respiration by activating Hcm1 and probably Hap4 to promote the superoxide production [32,33], it may also stimulate the stress response via Rim15 and its downstream factors [30]. The increased level of superoxide may also enhance the oxidative resistance as an adaptive ROS signaling [11]. Together, the deletion of SCH9 causes the up-regulation of the intracellular antioxidants and the decrease of H2O2, which damages intracellular proteins and subsequently causes ubiquitination. The plausible mechanisms by which Sch9 regulates protein ubiquitination are summarized in Fig. 7.

Bottom Line: In this study, we found that the overall level of ubiquitinated proteins dramatically decreased as yeast cell grew from log to stationary phase.Deletion of SCH9, a gene encoding a key protein kinase for longevity control, decreased the level of ubiquitinated proteins in log phase and this effect could be reversed by restoring Sch9 function.Our results revealed for the first time how Sch9 regulates the level of ubiquitinated proteins and provides new insight into how Sch9 controls longevity.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Bio-Resources and Eco-Environment of Ministry of Education, College of Life Science, Sichuan University, Chengdu, Sichuan 610064, China.

No MeSH data available.