ESCRT-III and ER-PM contacts maintain lipid homeostasis. Academic Article uri icon

Overview

abstract

  • Eukaryotic cells are compartmentalized into organelles by intracellular membranes. While the organelles are distinct, many of them make intimate contact with one another. These contacts were first observed in the 1950s, but only recently have the functions of these contact sites begun to be understood. In yeast, the endoplasmic reticulum (ER) makes extensive intermembrane contacts with the plasma membrane (PM), covering ∼40% of the PM. Many functions of ER-PM contacts have been proposed, including nonvesicular lipid trafficking, ion transfer, and as signaling hubs. Surprisingly, cells that lack ER-PM contacts grow well, indicating that alternative pathways may be compensating for the loss of ER-PM contact. To better understand the function of ER-PM contact sites we used saturating transposon mutagenesis to identify synthetic lethal mutants in a yeast strain lacking ER-PM contact sites. The strongest hits were components of the ESCRT complexes. The synthetic lethal mutants have low levels of some lipid species but accumulate free fatty acids and lipid droplets. We found that only ESCRT-III components are synthetic lethal, indicating that Vps4 and other ESCRT complexes do not function in this pathway. These data suggest that ESCRT-III proteins and ER-PM contact sites act in independent pathways to maintain lipid homeostasis.

publication date

  • April 8, 2020

Research

keywords

  • Cell Membrane
  • Endoplasmic Reticulum
  • Endosomal Sorting Complexes Required for Transport

Identity

PubMed Central ID

  • PMC7353149

Scopus Document Identifier

  • 85085631054

Digital Object Identifier (DOI)

  • 10.1091/mbc.E20-01-0061

PubMed ID

  • 32267208

Additional Document Info

volume

  • 31

issue

  • 12