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In vivo subcellular targeting analysis validates a novel peroxisome targeting signal type 2 and the peroxisomal localization of two proteins with putative functions in defense in Arabidopsis

Sheng Quan, Robert Switzenberg, Sigrun Reumann and Jianping Hu

Plant peroxisomes are essential organelles that house diverse metabolic activities. To understand the full spectrum of peroxisomal functions, we recently performed a proteomic analysis of Arabidopsis leaf peroxisomes followed by in vivo subcellular targeting validation of some novel proteins. Here, we continue with the targeting analysis and demonstrate that the nonapeptide RVx5HF, which is present near the N terminus of the newly identified peroxisomal protein, HIT3 (histidine triad family protein 3), is a functional peroxisome targeting signal type 2 (PTS2). In addition, we have confirmed the peroxisomal localization of UP6 (unknown protein 6) and GLX1 (glyoxalase 1 homolog), two proteins with possible roles in stress responses and glutathione-dependent detoxification, respectively. These data, together with results from our previous analysis of the peroxisomal proteome, reinforce the notion that peroxisomes are involved in various stress responses and suggest glutathione as a major antioxidant in plant peroxisomes.

Reumann S, Quan S, Aung K, Yang P, Shrestha K, Holbrook D, Linka N, Switzenberg, R, Wilkerson C, Weber AP, Olsen LJ, and Hu J. In-depth proteome analysis of Arabidopsis leaf peroxisomes combined with in vivo subcellular targeting verification indicates novel metabolic and regulatory functions of peroxisomes. Plant Physiol 2009; 150:125-43.

Authors

Sheng Quan

Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, MI USA.

Robert Switzenberg

Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, MI USA.

Sigrun Reumann

Centre for Organelle Research, Faculty of Science and Technology, University of Stavanger, Stavanger, Norway.

Jianping Hu Corresponding author: huji@msu.edu

Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, MI USA.