An ER surface retrieval pathway safeguards the import of mitochondrial membrane proteins in yeast

Abstract

ER-SURF protein import into mitochondria Eukaryotic cells contain membrane-bound organelles, defined by distinct protein compositions. Almost all cellular proteins are synthesized in the cytosol, and thus, organelle-resident proteins must be directed to their appropriate location after synthesis. Working in yeast, Hansen et al. identified a protein-targeting paradigm termed ER-SURF, in which the membrane expanse of the endoplasmic reticulum (ER) serves as a “capture net” for mitochondrial proteins. This process productively redirected mitochondrial precursor proteins for efficient mitochondrial import. Thus, two distinct organelles, once thought to be mutually exclusive protein destinations, can cooperate during protein targeting. Science , this issue p. 1118