The cadherin super family comprises a large number of membrane glycoproteins with one or more cadherin repeats, which are involved in Ca2+ dependent cell-cell adhesion. Cadherin-11, also known as OB-cadherin, is a type II classical cadherin. Classical cadherins are type I transmembrane proteins with an N-terminal extracellular domain containing five tandem cadherin repeats and a C-terminal cytoplasmic domain with a characteristic sequence for binding to catenins. Type I cadherins differ from type II cadherins by the presence of the HAV tripeptide motif in the most N-terminal cadherin repeat. Classic cadherins mediate cell-cell adhesion preferentially via homotypic interactions and form adherens juctions that have beta -catenin and p120 (ctn) at the cytoplasmic side of the junction. Homotypic cadherin interactions also transduce outside-in and inside-out cell signals.