Publication Information
Zhang et al., 2013
Abstract
Mol Cell Proteomics. 2013 May;12(5):1158-69. doi: 10.1074/mcp.M112.021220. Epub
2013 Jan 17.
Quantitative phosphoproteomics after auxin-stimulated lateral root induction
identifies an SNX1 protein phosphorylation site required for growth.
Zhang H(1), Zhou H, Berke L, Heck AJ, Mohammed S, Scheres B, Menke FL.
Author information:
(1)Bijvoet Center for Biomolecular Research, and Utrecht Institute for
Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands.
Protein phosphorylation is instrumental to early signaling events. Studying
system-wide phosphorylation in relation to processes under investigation
requires a quantitative proteomics approach. In Arabidopsis, auxin application
can induce pericycle cell divisions and lateral root formation. Initiation of
lateral root formation requires transcriptional reprogramming following
auxin-mediated degradation of transcriptional repressors. The immediate early
signaling events prior to this derepression are virtually uncharacterized. To
identify the signal molecules responding to auxin application, we used a lateral
root-inducible system that was previously developed to trigger synchronous
division of pericycle cells. To identify and quantify the early signaling events
following this induction, we combined (15)N-based metabolic labeling and
phosphopeptide enrichment and applied a mass spectrometry-based approach. In
total, 3068 phosphopeptides were identified from auxin-treated root tissue. This
root proteome dataset contains largely phosphopeptides not previously reported
and represents one of the largest quantitative phosphoprotein datasets from
Arabidopsis to date. Key proteins responding to auxin treatment included the
multidrug resistance-like and PIN2 auxin carriers, auxin response factor2
(ARF2), suppressor of auxin resistance 3 (SAR3), and sorting nexin1 (SNX1).
Mutational analysis of serine 16 of SNX1 showed that overexpression of the
mutated forms of SNX1 led to retarded growth and reduction of lateral root
formation due to the reduced outgrowth of the primordium, showing proof of
principle for our approach.
DOI: 10.1074/mcp.M112.021220
PMCID: PMC3650328
PMID: 23328941 [Indexed for MEDLINE]
