1. Enzymes degraded under high light maintain proteostasis by transcriptional regulation in Arabidopsis .
- Author
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Li L, Duncan O, Ganguly DR, Lee CP, Crisp PA, Wijerathna-Yapa A, Salih K, Trösch J, Pogson BJ, and Millar AH
- Subjects
- Light, Photosystem II Protein Complex genetics, Photosystem II Protein Complex metabolism, Arabidopsis enzymology, Arabidopsis genetics, Arabidopsis radiation effects, Arabidopsis Proteins genetics, Arabidopsis Proteins metabolism, Proteolysis radiation effects, Proteostasis genetics, Proteostasis radiation effects, Transcription, Genetic radiation effects
- Abstract
Photoinhibitory high light stress in Arabidopsis leads to increases in markers of protein degradation and transcriptional up-regulation of proteases and proteolytic machinery, but proteostasis is largely maintained. We find significant increases in the in vivo degradation rate for specific molecular chaperones, nitrate reductase, glyceraldehyde-3 phosphate dehydrogenase, and phosphoglycerate kinase and other plastid, mitochondrial, peroxisomal, and cytosolic enzymes involved in redox shuttles. Coupled analysis of protein degradation rates, mRNA levels, and protein abundance reveal that 57% of the nuclear-encoded enzymes with higher degradation rates also had high light–induced transcriptional responses to maintain proteostasis. In contrast, plastid-encoded proteins with enhanced degradation rates showed decreased transcript abundances and must maintain protein abundance by other processes. This analysis reveals a light-induced transcriptional program for nuclear-encoded genes, beyond the regulation of the photosystem II (PSII) D1 subunit and the function of PSII, to replace key protein degradation targets in plants and ensure proteostasis under high light stress.
- Published
- 2022
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