Lipid transport required to make lipids of photosynthetic membranes

Authors

Evan LaBrant, University of Nebraska–LincolnFollow
Allison C. Barnes, University of Nebraska–LincolnFollow
Rebecca Roston, University of Nebraska- LincolnFollow

ORCID IDs

Rebecca Roston 0000-0002-3063-5002

Evan LaBrant 0000-0003-0742-9363

Allison Barnes 0000-0001-9539-3297

Date of this Version

6-30-2018

Citation

Published in Photosynthesis Research, 2018

https://doi.org/10.1007/s11120-018-0545-5

Comments

Copyright © 2018 Springer Nature B.V. Used by permission.

A full-text view-only version of this paper is available from the publisher at this link: https://rdcu.be/2feb

Abstract

Photosynthetic membranes provide much of the usable energy for life on earth. To produce photosynthetic membrane lipids, multiple transport steps are required, including fatty acid export from the chloroplast stroma to the endoplasmic reticulum, and lipid transport from the endoplasmic reticulum to the chloroplast envelope membranes. Transport of hydrophobic molecules through aqueous space is energetically unfavorable and must be catalyzed by dedicated enzymes, frequently on specialized membrane structures. Here, we review photosynthetic membrane lipid transport to the chloroplast in the context of photosynthetic membrane lipid synthesis. We independently consider the identity of transported lipids, the proteinaceous transport components, and membrane structures which may allow efficient transport. Recent advances in lipid transport of chloroplasts, bacteria and other systems strongly suggest that lipid transport is achieved by multiple mechanisms which include membrane contact sites with specialized protein machinery. This machinery is likely to include the TGD1, 2, 3 complex with the TGD5 and TGD4/LPTD1 systems, and may also include a number of proteins with domains similar to other membrane contact site lipid-binding proteins. Importantly, the likelihood of membrane contact sites does not preclude lipid transport by other mechanisms including vectorial acylation and vesicle transport. Substantial progress is needed to fully understand all photosynthetic membrane lipid transport processes and how they are integrated.