ERGIC-53 and traffic in the secretory pathway

The ER-Golgi intermediate compartment (ERGIC) marker ERGIC-53 is a mannose- specific membrane lectin operating as a cargo receptor for the transport of glycoproteins from the ER to the ERGIC, Lack of functional ERGIC-53 leads to a selective defect in secretion of glycoproteins in cultured cells and t o hemophilia in humans, Beyond its interest as a transport receptor, ERGIC- 53 is an attractive probe for studying numerous aspects of protein traffick ing in the secretory pathway, including traffic routes, mechanisms of anter ograde and retrograde traffic, retention of proteins in the ER, and the fun ction of the ERGIC, Understanding these fundamental processes of cell biolo gy will be crucial for the elucidation and treatment of many inherited and acquired diseases, such as cystic fibrosis, Alzheimer's disease and viral i nfections.