Within the ER lumen, numerous molecular chaperones transiently bind nascent proteins and facilitate their folding or assembly. The action of chaperones ensures proper folding and, in turn, transport of new proteins from the rough ER to the Golgi complex. Some chaperones (grp78/Bip) bind to exposed hydrophobic segments, while others (ERp59/PDI) are involved in disulfide isomerization. An ERp59/PDI related protein, ERp72, contains three copies of the PDI acitve site, CGHC. Although ERp72 participates in disulfide isomerization, it is unclear whether it functions alone or in conjunction with other chaperones, specifically other members of the CGHC-containing protein family. Many chaperones, including PDI, are held within the ER via the common C-terminal KDEL sequence. ERp72 contains a related KEEL sequence that is essential for its ER retention. Additional studies have shown that ERp72 is a protease and a member of the thioredoxin superfamily known to bind Ca2+. Thus, ERp72 functions as a Ca2+-dependent chaperone with disulfide isomerization activity, but also may undertake other, yet undefined, roles within the ER.
This antibody is routinely tested by western blot analysis. Other applications were tested at BD Biosciences Pharmingen during antibody development only or reported in the literature.