Sensing and signaling of oxidative stress in chloroplasts by inactivation of the SAL1 phosphoadenosine phosphatase.
Kai Xun ChanPeter D MabbittSu Yin PhuaJonathan W MuellerNazia NisarTamara GigolashviliElke StroeherJulia GrasslWiebke ArltGonzalo M EstavilloColin J JacksonBarry J PogsonPublished in: Proceedings of the National Academy of Sciences of the United States of America (2016)
Intracellular signaling during oxidative stress is complex, with organelle-to-nucleus retrograde communication pathways ill-defined or incomplete. Here we identify the 3'-phosphoadenosine 5'-phosphate (PAP) phosphatase SAL1 as a previously unidentified and conserved oxidative stress sensor in plant chloroplasts. Arabidopsis thaliana SAL1 (AtSAL1) senses changes in photosynthetic redox poise, hydrogen peroxide, and superoxide concentrations in chloroplasts via redox regulatory mechanisms. AtSAL1 phosphatase activity is suppressed by dimerization, intramolecular disulfide formation, and glutathionylation, allowing accumulation of its substrate, PAP, a chloroplast stress retrograde signal that regulates expression of plastid redox associated nuclear genes (PRANGs). This redox regulation of SAL1 for activation of chloroplast signaling is conserved in the plant kingdom, and the plant protein has evolved enhanced redox sensitivity compared with its yeast ortholog. Our results indicate that in addition to sulfur metabolism, SAL1 orthologs have evolved secondary functions in oxidative stress sensing in the plant kingdom.
Keyphrases
- oxidative stress
- hydrogen peroxide
- arabidopsis thaliana
- dna damage
- diabetic rats
- transcription factor
- ischemia reperfusion injury
- induced apoptosis
- cell wall
- nitric oxide
- electron transfer
- poor prognosis
- genome wide
- signaling pathway
- dna methylation
- saccharomyces cerevisiae
- stress induced
- reactive oxygen species
- small molecule
- amino acid
- heat shock
- protein protein
- structural basis