The chloroplast envelope proteome and lipidome

Abstract

The lipid and protein components of the two envelope membranes, which delimit the chloroplast from the surrounding cytosol, have been extensively analyzed. Envelope membranes contain a wide diversity of glycolipids, pigments, and prenylquinones and play a key role in their synthesis, and also in the formation of various lipid-derived signaling molecules (chlorophyll precursors, abscisic acid, and jasmonate precursors, for instance). Many of the enzymes involved were identified by proteomics. Here, we present a curated protein list established from chloroplast envelope proteomes analyzed by different groups. The envelope proteome contains key proteins involved in the regulation of metabolic pathways, in cell signaling (and especially in plastid-to-nucleus signaling), in stress responses, etc. A series of transport systems for proteins, metabolites, and ions have also been identified by proteomics. Chloroplasts have had a long and complex evolutionary past and integration of the envelope membranes in cellular functions is the result of this evolution. The lipid and protein equipment of this plastid-specific membrane system reflect both its prokaryotic and eukaryotic origin. © 2009 Springer Berlin Heidelberg.