A role for cadherins in cellular signaling and differentiation.

Cadherins form a family of cell-cell adhesion proteins that are critical to normal embryonic development. Expression of the various family members is regulated in a complex pattern during embryogenesis. Both reduced and inappropriate expression of cadherins have been associated with abnormal tissue formation in embryos and tumorigenesis in mature organisms. Evidence is accumulating that signals unique to individual members of the cadherin family, as well as signals common to multiple cadherins, contribute to the differentiated phenotype of various cell types. While a complete understanding of the regulation of cadherin expression of the molecular nature of intracellular signaling downstream of cadherin adhesion is essential to an understanding of embryogenesis and tumorigenesis, our knowledge in both areas is inadequate. Clearly, elucidating the factors and conditions that regulate cadherin expression and defining the signaling pathways activated by cadherins are frontiers for future research.