title: The distinct functional roles of the inner and outer chloroplast envelope of Pea (Pisum sativum) as revealed by proteomic approaches.
abstract: Protein profiles of inner (IE) and outer (OE) chloroplast envelope membrane preparations from pea were studied using shotgun nLC-MS/MS and two-dimensional electrophoresis, and 589 protein species (NCBI entries) were identified. The relative enrichment of each protein in the IE/OE pair of membranes was used to provide an integrated picture of the chloroplast envelope. From the 546 proteins identified with shotgun, 321 showed a significant differential distribution, with 180 being enriched in IE and 141 in OE. To avoid redundancy and facilitate in silico localization, Arabidopsis homologues were used to obtain a nonredundant list of 409 envelope proteins, with many showing significant OE or IE enrichment. Functional classification reveals that IE is a selective barrier for transport of many metabolites and plays a major role in controlling protein homeostasis, whereas proteins in OE are more heterogeneous and participate in a wide range of processes. Data support that metabolic processes previously described to occur in the envelope such as chlorophyll and tocopherol biosynthesis can be ascribed to the IE, whereas others such as carotenoid or lipid biosynthesis occur in both membranes. Furthermore, results allow empirical assignation to the IE and/or OE of many proteins previously assigned to the bulk chloroplast envelope proteome.
authors.affiliation: Plant Nutrition Department, Aula Dei Experimental Station, CSIC , P.O. Box 13034, 50080 Zaragoza, Spain.
authors.forename: Elain
authors.initials: E
authors.lastname: Gutierrez-Carbonell
authors.forename: Daisuke
authors.initials: D
authors.lastname: Takahashi
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Lattanzio
authors.forename: Jorge
authors.initials: J
authors.lastname: Rodríguez-Celma
authors.forename: Julia
authors.initials: J
authors.lastname: Kehr
authors.forename: Jürgen
authors.initials: J
authors.lastname: Soll
authors.forename: Katrin
authors.initials: K
authors.lastname: Philippar
authors.forename: Matsuo
authors.initials: M
authors.lastname: Uemura
authors.forename: Javier
authors.initials: J
authors.lastname: Abadía
authors.forename: Ana Flor
authors.initials: AF
authors.lastname: López-Millán
mesh_terms: D001692:Biological Transport; D053898:Biosynthetic Pathways; D002734:Chlorophyll / Q000096:biosynthesis; D060365:Chloroplast Proteins / Q000302:isolation & purification / Q000378:metabolism*; D002736:Chloroplasts / Q000378:metabolism*; D015180:Electrophoresis, Gel, Two-Dimensional; D006706:Homeostasis; D007425:Intracellular Membranes / Q000378:metabolism; D050356:Lipid Metabolism; D008565:Membrane Proteins / Q000302:isolation & purification / Q000378:metabolism*; D058977:Molecular Sequence Annotation; D018532:Pisum sativum / Q000378:metabolism*; D020543:Proteome / Q000302:isolation & purification / Q000378:metabolism*; D040901:Proteomics; D024505:Tocopherols / Q000378:metabolism
chemical_list: D060365:Chloroplast Proteins; D008565:Membrane Proteins; D020543:Proteome; D002734:Chlorophyll; D024505:Tocopherols