Epithelial Membrane Protein 3 (EMP3)

By homology screening of databases, Ben-Porath and Benvenisty (1996) and Taylor and Suter (1996) independently identified a cDNA encoding epithelial membrane protein-3 (EMP3). The open reading frame predicts a 163-amino acid protein containing 4 transmembrane domains and 2 N-linked glycosylation sites in the first extracellular loop. Taylor and Suter (1996) showed that the EMP3 cDNA generates an 18-kD protein in vitro. The EMP3 amino acid sequence is 41% and 38% identical to those of peripheral myelin protein-22 (PMP22) and EMP2, respectively, with the highest homology found in the transmembrane domains. Due to the high amino acid sequence homology among PMP22, EMP1, EMP2, and EMP3, Ben-Porath and Benvenisty (1996) stated that these proteins comprise a novel family.