ER-associated VAP27-1 and VAP27-3 proteins functionally link the lipid-binding ORP2A at the ER-chloroplast contact sites.

Autor: Renna L; MSU-DOE Plant Research Lab, Michigan State University, East Lansing, MI, USA.; Department of Horticulture, University of Florence, Florence, Italy., Stefano G; MSU-DOE Plant Research Lab, Michigan State University, East Lansing, MI, USA.; Department of Plant Biology, Michigan State University, East Lansing, MI, USA.; Department of Biology, University of Florence, Florence, Italy., Puggioni MP; MSU-DOE Plant Research Lab, Michigan State University, East Lansing, MI, USA.; Department of Plant Physiology, Umeå Plant Science Centre, Umeå University, Umeå, Sweden., Kim SJ; MSU-DOE Plant Research Lab, Michigan State University, East Lansing, MI, USA.; Department of Plant Biology, Michigan State University, East Lansing, MI, USA.; Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, MI, USA., Lavell A; MSU-DOE Plant Research Lab, Michigan State University, East Lansing, MI, USA., Froehlich JE; MSU-DOE Plant Research Lab, Michigan State University, East Lansing, MI, USA.; Biochemistry and Molecular Biology Department, Michigan State University, East Lansing, MI, USA., Burkart G; MSU-DOE Plant Research Lab, Michigan State University, East Lansing, MI, USA., Mancuso S; Department of Horticulture, University of Florence, Florence, Italy.; Fondazione per il Futuro delle Città, Florence, Italy., Benning C; MSU-DOE Plant Research Lab, Michigan State University, East Lansing, MI, USA.; Department of Plant Biology, Michigan State University, East Lansing, MI, USA.; Biochemistry and Molecular Biology Department, Michigan State University, East Lansing, MI, USA., Brandizzi F; MSU-DOE Plant Research Lab, Michigan State University, East Lansing, MI, USA. fb@msu.edu.; Department of Plant Biology, Michigan State University, East Lansing, MI, USA. fb@msu.edu.; Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, MI, USA. fb@msu.edu.
Jazyk: angličtina
Zdroj: Nature communications [Nat Commun] 2024 Jul 17; Vol. 15 (1), pp. 6008. Date of Electronic Publication: 2024 Jul 17.
DOI: 10.1038/s41467-024-50425-7
Abstrakt: The plant endoplasmic reticulum (ER) contacts heterotypic membranes at membrane contact sites (MCSs) through largely undefined mechanisms. For instance, despite the well-established and essential role of the plant ER-chloroplast interactions for lipid biosynthesis, and the reported existence of physical contacts between these organelles, almost nothing is known about the ER-chloroplast MCS identity. Here we show that the Arabidopsis ER membrane-associated VAP27 proteins and the lipid-binding protein ORP2A define a functional complex at the ER-chloroplast MCSs. Specifically, through in vivo and in vitro association assays, we found that VAP27 proteins interact with the outer envelope membrane (OEM) of chloroplasts, where they bind to ORP2A. Through lipidomic analyses, we established that VAP27 proteins and ORP2A directly interact with the chloroplast OEM monogalactosyldiacylglycerol (MGDG), and we demonstrated that the loss of the VAP27-ORP2A complex is accompanied by subtle changes in the acyl composition of MGDG and PG. We also found that ORP2A interacts with phytosterols and established that the loss of the VAP27-ORP2A complex alters sterol levels in chloroplasts. We propose that, by interacting directly with OEM lipids, the VAP27-ORP2A complex defines plant-unique MCSs that bridge ER and chloroplasts and are involved in chloroplast lipid homeostasis.
(© 2024. The Author(s).)
Databáze: MEDLINE
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