A distinct linker mediating ER-autophagosome membrane contact site (EACS) in plants

Autophagy. 2023 Sep;19(9):2616-2617. doi: 10.1080/15548627.2023.2176028. Epub 2023 Feb 7.

Abstract

Endoplasmic reticulum (ER) membrane contacts play a central role in regulating autophagosome formation in yeast and mammals. However, a direct functional linkage between the ER and autophagosomes in plants remains elusive. We have recently identified and characterized a plant-unique protein complex consisting of AT4G22540/OSBP2A/ORP2A (oxysterol binding protein-related protein 2A), the ER resident protein AT3G60600/VAP27-1 (vesicle-associated protein 27-1) and AT2G45170/ATG8e (autophagy related 8e) that mediate the ER-autophagosome membrane contact site (EACS) in the model plant Arabidopsis thaliana. Knockdown (KD) of ORP2A affects autophagosome formation and seedling development, whereas ORP2A KD root cells show accumulation of the macroautophagic/autophagic core machinery and PtdIns3P in enlarged ER membranes under autophagy conditions. This study reveals the molecular architecture and functions of a distinct plant EACS in regulating autophagosome formation via lipid redistribution.

Keywords: Arabidopsis; ORP; PtdIns3P; autophagosome; membrane contact site.

Publication types

  • Research Support, Non-U.S. Gov't
  • Comment

MeSH terms

  • Animals
  • Arabidopsis* / metabolism
  • Autophagosomes* / metabolism
  • Autophagy / physiology
  • Endoplasmic Reticulum / metabolism
  • Mammals
  • Mitochondrial Membranes

Grants and funding

Our research have been supported by grants from the National Natural Science Foundation of China (91854201), the Research Grants Council of Hong Kong. (AoE/M-05/12, CUHK14101219, C4033-19E, C4002-20W, C4002-21EF, C2009-19G, C2003-22WF, R4005-18 and Senior Research Fellow Scheme SRFS2122-4S01), The Chinese University of Hong Kong (CUHK) Research Committee, and CAS-Croucher Funding Scheme for Joint Laboratories to L.J.