The C-terminal domain of yeast Ero1p mediates membrane localization and is essential for function

In eukaryotes, members of the Ero1 family control oxidative protein folding in the endoplasmic reticulum (ER). Yeast Ero1p is tightly associated with the ER membrane, despite cleavage of the leader peptide, the only hydrophobic sequence that could mediate lipid insertion. In contrast, human Ero1-L? and a yeast mutant (Ero1p?C) lacking the 127 C-terminal amino acids are soluble when expressed in yeast. Neither Ero1-L? nor Ero1p?C complements an ERO1 disrupted strain. Appending the yeast C-terminal tail to human Ero1-L? restores membrane association and allows growth of ERO1 disrupted cells. Therefore, the tail of Ero1p mediates membrane association and is crucial for function. © 2001 Published by Elsevier Science B.V. on behalf of the Federation of European Biochemical Societies.