Quantitative Phosphoproteomics after Auxin-stimulated Lateral Root Induction Identifies an SNX1 Protein Phosphorylation Site Required for Growth

摘要: Protein phosphorylation is instrumental to early signaling events. Studying system-wide in relation processes under investigation requires a quantitative proteomics approach. In Arabidopsis, auxin application can induce pericycle cell divisions and lateral root formation. Initiation of formation transcriptional reprogramming following auxin-mediated degradation repressors. The immediate events prior this derepression are virtually uncharacterized. To identify the signal molecules responding application, we used root-inducible system that was previously developed trigger synchronous division cells. quantify induction, combined 15N-based metabolic labeling phosphopeptide enrichment applied mass spectrometry-based total, 3068 phosphopeptides were identified from auxin-treated tissue. This proteome dataset contains largely not reported represents one largest phosphoprotein datasets Arabidopsis date. Key proteins treatment included multidrug resistance-like PIN2 carriers, AUXIN RESPONSE FACTOR2 (ARF2), SUPPRESSOR OF RESISTANCE 3 (SAR3), SORTING NEXIN1 (SNX1). Mutational analysis serine 16 SNX1 showed overexpression mutated forms led retarded growth reduction due reduced outgrowth primordium, showing proof principle for our