Heat Shock Factor HSFA6b Mediates Mitochondrial Unfolded Protein Response in <i>Arabidopsis thaliana</i>
Mitochondria are important organelles in eukaryotes and are involved in various metabolic processes. Mitochondrial proteotoxic stress triggers the mitochondrial unfolded protein response (UPR<sup>mt</sup>) to restore mitochondrial protein homeostasis and maintain normal life activities....
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| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2024-11-01
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| Series: | Plants |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2223-7747/13/22/3116 |
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| Summary: | Mitochondria are important organelles in eukaryotes and are involved in various metabolic processes. Mitochondrial proteotoxic stress triggers the mitochondrial unfolded protein response (UPR<sup>mt</sup>) to restore mitochondrial protein homeostasis and maintain normal life activities. However, the regulatory mechanism of plant UPR<sup>mt</sup> remains to be revealed in Arabidopsis. Based on the fact that UPR<sup>mt</sup> activates heat shock protein (<i>HSP</i>) genes, we identified the heat shock transcription factor <i>HSFA6b</i> as a key regulator mediating UPR<sup>mt</sup> through reverse genetics. <i>HSFA6b</i> responded to mitochondrial proteotoxic stress and regulated mitochondrial heat shock proteins’ genes’ (<i>mtHSPs</i>) expression. HSFA6b translocated to the nuclear after treatment with doxycycline (Dox)—a mitochondrial ribosome translation inhibitor. HSFA6b binds to the <i>mtHSPs</i> promoters and activates <i>mtHSPs</i> expression. The <i>HSFA6b</i> mutation blocked the UPR<sup>mt</sup> signals to promote root growth under mitochondrial proteotoxic stress and accelerated leaf senescence during development. Our study reveals a novel signal-regulating mechanism in the UPR<sup>mt</sup> pathways and provides new insights regarding the regulation of plant growth and development and stress resistance by the UPR<sup>mt</sup> pathways. |
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| ISSN: | 2223-7747 |