title: In-depth proteome analysis of Arabidopsis leaf peroxisomes combined with in vivo subcellular targeting verification indicates novel metabolic and regulatory functions of peroxisomes.
abstract: 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. We detected 65 established plant peroxisomal proteins, 30 proteins whose association with Arabidopsis peroxisomes had been previously demonstrated only by proteomic data, and 55 putative novel proteins of peroxisomes. We subsequently tested the subcellular targeting of yellow fluorescent protein fusions for selected proteins and confirmed the peroxisomal localization for 12 proteins containing predicted peroxisome targeting signals type 1 or 2 (PTS1/2), three proteins carrying PTS-related peptides, and four proteins that lack conventional targeting signals. We thereby established the tripeptides SLM> and SKV> (where > indicates the stop codon) as new PTS1s and the nonapeptide RVx(5)HF as a putative new PTS2. The 19 peroxisomal proteins conclusively identified from this study potentially carry out novel metabolic and regulatory functions of peroxisomes. Thus, this study represents an important step toward defining the complete plant peroxisomal proteome.
authors.affiliation: Michigan State University-Department of Energy Plant Research Laboratory , Michigan State University, East Lansing, Michigan 48824, USA.
authors.forename: Sigrun
authors.initials: S
authors.lastname: Reumann
authors.forename: Sheng
authors.initials: S
authors.lastname: Quan
authors.forename: Kyaw
authors.initials: K
authors.lastname: Aung
authors.forename: Pingfang
authors.initials: P
authors.lastname: Yang
authors.forename: Kalpana
authors.initials: K
authors.lastname: Manandhar-Shrestha
authors.forename: Danielle
authors.initials: D
authors.lastname: Holbrook
authors.forename: Nicole
authors.initials: N
authors.lastname: Linka
authors.forename: Robert
authors.initials: R
authors.lastname: Switzenberg
authors.forename: Curtis G
authors.initials: CG
authors.lastname: Wilkerson
authors.forename: Andreas P M
authors.initials: AP
authors.lastname: Weber
authors.forename: Laura J
authors.initials: LJ
authors.lastname: Olsen
authors.forename: Jianping
authors.initials: J
authors.lastname: Hu