Important in cell-cell recognition. Appears to function in leukocyte-endothelial cell adhesion. Interacts with integrin alpha-4/beta-1 (ITGA4/ITGB1) on leukocytes, and mediates both adhesion and signal transduction. The VCAM1/ITGA4/ITGB1 interaction may play a pathophysiologic role both in immune responses and in leukocyte emigration to sites of inflammation. Additional isoforms seem to exist. Expressed on inflamed vascular endothelium, as well as on macrophage-like and dendritic cell types in both normal and inflamed tissue. By cytokines (e.g. IL-1, TNF-alpha). Either the first or the fourth Ig-like C2-type domain is required for VLA4-dependent cell adhesion. Sialoglycoprotein. Major isoform. VCAM1 entry VCAM-1