Organization of the genes encoding selected Ig-CAMs and Ig-ITIM family members. Note that Ig-ITIM family genes often contain a mini-exon encoding all or part of the signal peptide, and their cytoplasmic domains are encoded by multiple exons. Both of these features differ significantly from that of Ig-CAMs, in which the transmembrane and cytoplasmic domains, as well as the 3′-untranslated region, are often encoded by a single, fused exon. ICAM-1, intercellular cell adhesion molecule-1; Ig-CAMs, Ig-like cell adhesion molecules; VCAM-1, vascular cell adhesion molecule-1.