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Lipid Transport Involving Chloroplast Envelope Membranes in Plants and Algae
Author(s) -
Benning Christoph,
Hurlock Anna,
Warakat Jaruswan
Publication year - 2015
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.29.1_supplement.366.1
Subject(s) - chlamydomonas , chloroplast membrane , arabidopsis , chloroplast , endoplasmic reticulum , microbiology and biotechnology , arabidopsis thaliana , biology , biochemistry , mutant , chemistry , thylakoid , gene
Lipid trafficking between the endoplasmic reticulum (ER) and chloroplasts is essential in plant cells and involves two transport complexes in the inner and outer envelope membrane, respectively. The TGD1,2,3 ABC transporter complex so named after the accumulation of trigalactosyldiacylglycerol in the Arabidopsis mutants, consists of a permease (TGD1), an ATPase (TGD3), and substrate binding protein (TGD2). It is located in the inner envelope membrane, but TGD2 is proposed to reach out to the outer envelope membrane to facilitate lipid transfer. TGD4 forms a complex in the outer envelope membrane. TGD2 as well as TGD4 bind phosphatidic acid. However, the actual transported substrates remain to be defined. Novel in vivo and in vitro approaches are applied to address this issue. Until recently, the green alga Chlamydomonas was not thought to utilize lipid precursors from the ER for the assembly of chloroplast lipids. However, the isolation and analysis of a TGD2 loss‐of‐function mutant of Chlamydomonas suggest that ER to chloroplast lipid transfer takes place in this alga. However, phenotypes of the respective mutants in Arabidopsis and Chlamydomonas differ in specific aspects that may shed new light onto the function of these complexes in Chlamydomonas and Arabidopsis.