Molecular cloning and characterization of a novel human classic cadherin homologous with mouse muscle cadherin

We used a novel cDNA cloning method based on the cadherin-beta-catenin protein interaction and identified a new human classic-type cadherin, which we named cadherin-15, from adult brain and skeletal muscle cDNA libraries. Sequence analysis revealed that this cadherin was closely related to mouse muscle cadherin and seemed to be its human counterpart. However, its deduced amino acid sequence differed from that of mouse muscle cadherin in that it had an extra 31-amino acid sequence at its C terminus that has been found neither in mouse muscle cadherin nor in any other known classic cadherin. Analysis of cadherin-15 protein expressed in L fibroblasts showed that it was cleaved proteolytically, expressed on the cell surfaces as a mature form of about 124-kDa, and functioned as a cell-cell adhesion molecule in a homophilic and specific manner, but Ca2+ did not protect it against degradation by trypsin. Our findings also suggest that cadherin-15 mediates cell-cell adhesion with a binding strength comparable to that of E-cadherin.