Review: Lutheran/B-CAM: A Laminin receptor on red blood cells and in various tissues

The Lutheran blood group glycoprotein (Lu), also known as basal cell adhesion molecule (B-CAM), is a transmembrane receptor with five immunoglobulin-like domains in its extracellular region; it is therefore classified as a member of the immunoglobulin (Ig) gene family. Lu/B-CAM is observed not only on red blood cells, but also on a subset of muscle and epithelial cells in various tissues. Recently, several groups have reported that Lu/B-CAM is a novel receptor for laminin a 5. The laminin a 5 chain is a component of the laminin-511 (α5β1γ1), -521 (α5β2γ1), and -523 (α5β2γ3) heterotrimers and is expressed throughout the mammalian body. We also have shown that Lu/B-CAM is co-localized with laminin a 5 in various tissues. Although the biological role of Lu/B-CAM remains unclear, the specific binding of Lu/B-CAM to laminin a 5 suggests that it plays an important role in developmental and physiological processes. It also is necessary to investigate further the interaction between Lu/B-CAM and laminin α 5 in pathological processes, including sickle cell disease and cancer.