ERO1-L, a human protein that favors disulfide bond formation in the endoplasmic reticulum.
Oxidizing conditions must be maintained in the endoplasmic reticulum (ER) to allow the formation of disulfide bonds in secretory proteins. Here we report the cloning and characterization of a mammalian gene (ERO1-L) that shares extensive homology with the Saccharomyces cerevisiae ERO1 gene, required in yeast for oxidative protein folding. When expressed in mammalian cells, the product of the human ERO1-L gene co-localizes with ER markers and displays Endo-H-sensitive glycans. In isolated microsomes, ERO1-L behaves as a type II integral membrane protein. ERO1-L is able to complement several phenotypic traits of the yeast thermosensitive mutant ero1-1, including temperature and dithiothreitol sensitivity, and intrachain disulfide bond formation in carboxypeptidase Y. ERO1-L is no longer functional when either one of the highly conserved Cys-394 or Cys-397 is mutated. These results strongly suggest that ERO1-L is involved in oxidative ER protein folding in mammalian cells.
Cabibbo
A
A
Department of Biological and Technological Research, San Raffaele Scientific Institute, Via Olgettina 58, 20132 Milano, Italy. caribbo.andrea@hsr.it
Pagani
M
M
Fabbri
M
M
Rocchi
M
M
Farmery
M R
MR
Bulleid
N J
NJ
Sitia
R
R
D000595:Amino Acid Sequence; D004220:Disulfides / Q000378:metabolism*; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D005816:Genetic Complementation Test; D006801:Humans; D007425:Intracellular Membranes / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008861:Microsomes / Q000378:metabolism; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D010088:Oxidoreductases; D050862:Oxidoreductases Acting on Sulfur Group Donors; D014176:Protein Biosynthesis; D017510:Protein Folding; D012441:Saccharomyces cerevisiae / Q000235:genetics; D017386:Sequence Homology, Amino Acid
D004220:Disulfides; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; C405327:ERO1A protein, human; D010088:Oxidoreductases; D050862:Oxidoreductases Acting on Sulfur Group Donors; C485767:ERO1B protein, human