Sensing and signaling of oxidative stress in chloroplasts by inactivation of the SAL1 phosphoadenosine phosphatase

Research output: Contribution to journalArticle


  • Kai Xun Chan
  • Peter Mabbitt
  • Su Yin Phua
  • Nazia Nisar
  • Tamara Gigolashvilli
  • Elke Stroeher
  • Julia Grassl
  • Gonzalo Estavillo
  • Colin Jackson
  • Barry Pogson

Colleges, School and Institutes

External organisations

  • ARC Centre of Excellence in Plant Energy Biology, Research School of Biology, Australian National University, Acton ACT 2601, Australia
  • Botanical Institute and Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, 50674 Cologne, Germany
  • ARC Centre of Excellence in Plant Energy Biology, University of Western Australia, Crawley WA 6009, Australia
  • Research School of Chemistry, Australian National University, Acton ACT 2601, Australia


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 novel 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 to 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.


Original languageEnglish
Pages (from-to)E4567-E4576
JournalNational Academy of Sciences. Proceedings
Issue number31
Early online date18 Jul 2016
Publication statusPublished - 2 Aug 2016