Proteomic Analysis of a Poplar Cell Suspension Culture Suggests a Major Role of Protein S-Acylation in Diverse Cellular Processes.

Vaibhav Srivastava,Vincent Bulone,Joseph R. Weber,Erik Malm,Bruce W. Fouke

doi:10.3389/fpls.2016.00477

Abstract

S-acylation is a reversible post-translational modification of proteins known to be involved in membrane targeting, subcellular trafficking, and the determination of a great variety of functional properties of proteins. The aim of this work was to identify S-acylated proteins in poplar. The use of an acyl-biotin exchange method and mass spectrometry allowed the identification of around 450 S-acylated proteins, which were subdivided into three major groups of proteins involved in transport, signal transduction, and response to stress, respectively. The largest group of S-acylated proteins was the protein kinase superfamily. Soluble N-ethylmaleimide-sensitive factor-activating protein receptors, band 7 family proteins and tetraspanins, all primarily related to intracellular trafficking, were also identified. In addition, cell wall related proteins, including cellulose synthases and other glucan synthases, were found to be S-acylated. Twenty four of the identified S-acylated proteins were also enriched in detergent-resistant membrane microdomains, suggesting S-acylation plays a key role in the localization of proteins to specialized plasma membrane subdomains. This dataset promises to enhance our current understanding of the various functions of S-acylated proteins in plants.

Highlights

The term S-acylation encapsulates the chemical linking of two molecules through the formation of a thioester bond (Conibear and Davis, 2010)
S-acylation is catalyzed by palmitoyl acyltransferases (PAT), known to contain DHHC-CRD required for activity (Lobo et al, 2002; Roth et al, 2002), whereas the reverse reaction is catalyzed by acyl protein thioesterases (APT; Mumby, 1997)
S-acylation is a common modification of both membrane and soluble proteins (Conibear and Davis, 2010; Levental et al, 2010; Yang et al, 2010; AicartRamos et al, 2011; Blaskovic et al, 2013), but our understanding of the role of this class of post-translational modification (PTM) in plants is not as advanced as in yeast and humans

Summary

Introduction

The term S-acylation encapsulates the chemical linking of two molecules through the formation of a thioester bond (Conibear and Davis, 2010). The most common type of S-acylation is palmitoylation (Wan et al, 2007; Conibear and Davis, 2010; Salaun et al, 2010). The first PATs were identified in the yeast Saccharomyces cerevisiae (Lobo et al, 2002; Roth et al, 2002) Following this discovery, several DHHC-CRD containing proteins have been reported in other species (Huang et al, 2004; Hemsley and Grierson, 2008; Ohno et al, 2012). PAT13 and PAT14 have both been shown to be involved in leaf senescence control (Lai et al, 2015; Li et al, 2015; Zhao et al, 2016)

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