protein_function: Cell adhesion molecule that mediates both heterotypiccell-cell contacts via its interaction with CD6, as well ashomotypic cell-cell contacts. Promotes T-cell activation andproliferation via its interactions with CD6 (By similarity).Contributes to the formation and maturation of the immunologicalsynapse via its interactions with CD6 (By similarity). Mediateshomotypic interactions with cells that express ALCAM. Mediatesattachment of dendritic cells onto endothelial cells via homotypicinteraction. Inhibits endothelial cell migration and promotesendothelial tube formation via homotypic interactions. Requiredfor normal organization of the lymph vessel network. Required fornormal hematopoietic stem cell engraftment in the bone marrow.Plays a role in hematopoiesis; required for normal numbers ofhematopoietic stem cells in bone marrow. Promotes in vitroosteoblast proliferation and differentiation (By similarity).Promotes neurite extension, axon growth and axon guidance; axonsgrow preferentially on surfaces that contain ALCAM (Bysimilarity). Mediates outgrowth and pathfinding for retinalganglion cell axons (By similarity)..
CD166 antigen is a 100-105 kD typeI transmembrane glycoprotein that is a member of the immunoglobulin superfamily of proteins. In humans it is encoded by the ALCAM gene. The human gene was mapped to chromosome 3q13.1-q13.2 by fluorescence in situ hybridization of cDNA probes to metaphase chromosomes. It is also called CD166 (cluster of differentiation 166), MEMD, SC-1,DM-GRASP,BEN in the chicken, and KG-CAM in the rat. This gene is expressed on activated T cells, activated monocytes, epithelial cells, fibroblasts, neurons, melanoma cells, and also in sweat and sebaceous glands. CD166 plays an important role in mediating adhesion interactions between thymic epithelial cells and CD6+ cells during intrathymic T cell development. Recently, CD166 has also been used as a potential cancer stem cell marker.