title: Phosphatidylcholine is transferred from chemically-defined liposomes to chloroplasts through proteins of the chloroplast outer envelope membrane.
abstract: Chloroplasts maintain their lipid balance through a tight interplay with the endoplasmic reticulum (ER). The outer envelope membrane of chloroplasts contains a large proportion of the phospholipid phosphatidylcholine (PC), which is synthesized in the ER and also a possible precursor for thylakoid galactolipids. The mechanism for PC transport from the ER to chloroplasts is not known. Using isolated chloroplasts and liposomes containing radiolabeled PC we investigated non-vesicular transport of PC in vitro. PC uptake in chloroplasts was time and temperature dependent, but nucleotide independent. Increased radius of liposomes stimulated PC uptake, and protease treatment of the chloroplasts impaired PC uptake. This implies that the chloroplast outer envelopes contains an exposed proteinaceous machinery for the uptake of PC from closely apposed membranes.
authors.affiliation: State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, People's Republic of China; Department of Biological and Environmental Sciences, University of Gothenburg, SE-405 30 Gothenburg, Sweden.
authors.forename: Congfei
authors.initials: C
authors.lastname: Yin
authors.affiliation: Department of Biological and Environmental Sciences, University of Gothenburg, SE-405 30 Gothenburg, Sweden.
authors.forename: Mats X
authors.initials: MX
authors.lastname: Andersson
authors.affiliation: State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, People's Republic of China. Electronic address: hszhang@njau.edu.cn.
authors.forename: Hongsheng
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Department of Biological and Environmental Sciences, University of Gothenburg, SE-405 30 Gothenburg, Sweden. Electronic address: henrik.aronsson@bioenv.gu.se.
authors.forename: Henrik
authors.initials: H
authors.lastname: Aronsson
mesh_terms: D001692:Biological Transport / Q000502:physiology; D007425:Intracellular Membranes / Q000737:chemistry / Q000378:metabolism*; D008081:Liposomes; D018532:Pisum sativum / Q000737:chemistry / Q000378:metabolism*; D010713:Phosphatidylcholines / Q000737:chemistry / Q000378:metabolism*; D020524:Thylakoids / Q000737:chemistry / Q000378:metabolism*
chemical_list: D008081:Liposomes; D010713:Phosphatidylcholines
keywords: Chloroplast; Lipid uptake; Liposome; Phosphatidylcholine (PC)