TY - JOUR
T1 - Sensing and signaling of oxidative stress in chloroplasts by inactivation of the SAL1 phosphoadenosine phosphatase
AU - Chan, Kai Xun
AU - Mabbitt, Peter D.
AU - Phua, Su Yin
AU - Mueller, Jonathan W.
AU - Nisar, Nazia
AU - Gigolashvili, Tamara
AU - Stroeher, Elke
AU - Grassl, Julia
AU - Arlt, Wiebke
AU - Estavillo, Gonzalo M.
AU - Jackson, Colin J.
AU - Pogson, Barry J.
PY - 2016/8/2
Y1 - 2016/8/2
N2 - 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 comparedwith 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.
AB - 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 comparedwith 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.
UR - http://www.scopus.com/inward/record.url?scp=84982735901&partnerID=8YFLogxK
U2 - 10.1073/pnas.1604936113
DO - 10.1073/pnas.1604936113
M3 - Article
SN - 0027-8424
VL - 113
SP - E4567-E4576
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 31
ER -