A High Content in Lipid-modified Peripheral Proteins and Integral Receptor Kinases Features in the Arabidopsis Plasma Membrane Proteome

Abstract

The proteomics of plasma membrane has brought to date only scarce and partial information on the actual protein repertoire. In this work, the plant plasma membrane proteome of Arabidopsis thaliana was investigated. A highly purified plasma membrane fraction was washed by NaCl and Na 2 CO 3 salts, and the insoluble fractions were further analyzed by nano-LC-MS/MS. With 446 proteins identified, we hereby describe the largest plasma membrane proteome diversity reported so far. Half of the proteins were predicted to display transmembrane domains and/or to be anchored to the membrane, validating a posteriori the pertinence of the approach. A fine analysis highlighted two main specific and novel features. First, the main functional category is represented by a majority of as yet unreported signaling proteins, including 11% receptor-like kinases. Second, 16% of the identified proteins are predicted to be lipid-modified, specifically involving double lipid linkage through N-terminal myristoylation, S-palmitoylation, C-terminal prenylation, or glycosylphosphatidylinositol anchors. Thus, our approach led for the first time to the identification of a large number of peripheral proteins as part of the plasma membrane and allowed the functionality of the plasma membrane in the cell context to be reconsidered.

Pseudomonas syringae type III effector HopAF1 suppresses plant immunity by targeting methionine recycling to block ethylene induction

“…2C). We conclude that wild-type HopAF1 and Arabidopsis MTNs interact specifically at the plasma membrane, as is consistent with the demonstrated localization of HopAF1 and with the observation that MTN1 and MTN2 may transiently localize to the plasma membrane via protein-protein interactions (60,62).…”

Cytosolic and Chloroplastic DHARs Cooperate in Oxidative Stress-Driven Activation of the Salicylic Acid Pathway

“…Interestingly, both of the DHARs we found to be cytosolic were identified in a proteomics study of proteins associating with the plasma membrane, along with several other GSTs and peroxidases (Marmagne et al, 2007). Proteins other than the three DHARs, such as certain glutaredoxins or GSTs (Chew et al, 2003;Dixon et al, 2009), may be responsible for DHAR activities reported previously to be associated with the peroxisomes and mitochondria.…”

“…Thus, cooperation between the DHARs, and particularly the cytosolic forms, is required to couple oxidative stress to the activation of downstream signaling. The importance of the cytosolic isoforms could be linked to their partial recruitment to the plasma membrane (Marmagne et al, 2007), possibly to set appropriate conditions for redox signaling at this location. However, the close correlation between glutathione and SA contents (Fig.…”

Definition of Arabidopsis Sterol-rich Membrane Microdomains by Differential Treatment with Methyl-β-cyclodextrin and Quantitative Proteomics

“…GPI-anchored proteins were annotated based on published literature and predictions (35)(36)(37). Graphs were created using SigmaPlot version 10 (Systat Software), and statistical tests were carried out using Excel Analyze-it package version 2.07.…”