P30040

Endoplasmic reticulum protein 29 (ERp29) is a protein which localizes to the lumen of the endoplasmic reticulum (ER). It is a member of the protein disulfide isomerase (PDI) protein family but lacks an active thioredoxin motif, suggesting that this protein does not function as a disulfide isomerase. The canonical protein dimerizes and is thought to play a role in the processing of secretory proteins within the ER. Alternative splicing results in multiple transcript variants encoding different isoforms. ERp29 contributes to GAP junction formation by stabilizing monomeric connexin 43, preventing premature oligomerization in the endoplasmic reticulum and allowing for efficient transport to the plasma membrane. ERp29 is thought to contribute to tumorigenesis in some human cancers, but acts as a tumor suppressor in gastric cancer.