Abstract 2268 Protein phosphatase SLP1 is a novel regulator of chloroplastic metabolism

This is the authors' abstract. We don't add key points for this paper.

Photosynthesis is one of the most important biological phenomena on the planet. One regulatory mechanism for this process is the post-translational modification of proteins involved in catalyzing the light (in)dependent reactions occurring at the chloroplast thylakoid membranes and stroma. Like in all other eukaryotes, protein phosphorylation is the most prevalent post-translational modification in plants and is controlled by protein phosphatases and protein kinases. In the chloroplast only a few protein phosphatases are well characterized, with their substrates mostly being thylakoid membrane proteins. Following our group's bioinformatic discovery of chloroplast stroma localized protein phosphatase Shewanella-like phosphatase 1 (SLP1), our phosphoproteomics study suggests that SLP1 regulates the phosphorylation status of 126 proteins in the chloroplast. This gives SLP1 a supposedly widespread role and places it at the center of chloroplastic metabolism. Now having a list of putative targets, we sought out to identify how the phospho-status of select SLP1 target proteins may influence plant biology in Arabidopsis. Our group uses a combination of molecular biology, omics, and classical biochemistry to study the pleiotropic activity of SLP1. Furthermore, using a slp1-/- line, we have found SLP1 to be critical for regular starch, sugar, and lipid accumulation in Arabidopsis; we hypothesize the phospho-status of SLP1 target proteins is responsible for these observed phenotypes.