Proteome analysis of peroxisomes from etiolated Arabidopsis seedlings identifies a peroxisomal protease involved in β-oxidation and development.

Plant peroxisomes are highly dynamic organelles that mediate a suite of metabolic processes crucial to development. Peroxisomes in seeds/dark-grown seedlings and in photosynthetic tissues constitute two major subtypes of plant peroxisomes, which had been postulated to contain distinct primary biochemical properties. Multiple in-depth proteomic analyses had been performed on leaf peroxisomes, yet the major makeup of peroxisomes in seeds or dark-grown seedlings remained unclear.

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.

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 RVxHF, 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-depth proteome analysis of Arabidopsis leaf peroxisomes combined with in vivo subcellular targeting verification indicates novel metabolic and regulatory functions of peroxisomes.

Peroxisomes are metabolically diverse organelles with essential roles in plant development. The major protein constituents of plant peroxisomes are well characterized, whereas only a few low-abundance and regulatory proteins have been reported to date. We performed an in-depth proteome analysis of Arabidopsis (Arabidopsis thaliana) leaf peroxisomes using one-dimensional gel electrophoresis followed by liquid chromatography and tandem mass spectrometry.