Table 1.

Summary of CAM family characteristics.

CAM Family/Approximate Number of Genes:	Subgroups/Approximate Number of Genes:	Basic Structural Properties/Domain Organization:	General Biological Functions:	Refs:
Cadherin Family - 125	• Major Cadherins- 32  • Protocadherins – 76  • Cadherin Related - 17	Characterized by the presence of at least two consecutive extracellular cadherin repeats with conserved calcium-binding pockets	Exhibit homotypic cell-cell adhesion, although heterotypic binding is possible, thus providing selectivity for cell sorting and transmitting cell-cell communication	1, 5, 11, 12
Integrin Family - 24	• α-subunits - 18  • β-subunits – 8	Type I transmembrane proteins containing large extracellular domains and generally short cytoplasmic domains. Functional receptors are heterodimers of an α and βsubunit.	Engage extracellular matrix macromolecules and/or counter-receptors on adjacent cell surfaces producing extracellular adhesions and intracellular signaling cascades.	2, 5, 9, 10
Selectin Family - 3	• E-selectin – 1  • P-selectin – 1  • L-selectin - 1	Single-chain transmembrane glycoproteins related to Ctype lectins through amino terminus similarities and calcium-dependent binding.	Mediates leukocyte cell tethering and rolling on endothelium through the recognition of sialyl-Lewis X tetrasaccharide carbohydrate moieties on glycoprotein ligands.	3, 5, 7, 8
Immunoglobulin Superfamily – 667+	• C1-set domain containing −42  • C2-set domain containing - 40  • Ig-like domain containing −261  • I-set domain containing −161  • V-set domain containing −163	Possess at least one Igdomain or Ig-like domain characterized by a domain size of ~100 amino acids, the number of beta-strands, and general topology of the Igfold.	Members function as cell adhesion molecules and antigen/cytokine/growth factor receptors and coreceptors important for adhesion, binding, signaling, and recognition processes.	4–6