The E-cadherin cell adhesion molecule is associated with cytoplasmic polypeptides, and this association is essential for its cell-binding function. Using isolated adherens junctions of the liver, we purified a 102 kd protein that can associate with E-cadherin (CAP102) and isolated cDNAs encoding this protein. Sequence analysis of the cDNAs revealed that this protein has a similarity to vinculin. L ceils not expressing endogenous cadherin express the mRNA for CAP102 but have only a trace amount of CAP102 protein. Introducing exogenous E-cadherin Into these cells, however, induced a high expression of CAP102 protein without affecting the amount of its mRNA, suggesting that there is a posttranscriptional regulatory mechanism for this molecule. The same effect was observed by introducing N-or P-cadherin into L cells. introduction

Cadherins are a family of transmembrane glycoproteins responsible for C3+-dependent cell-cell adhesion (Takeichi, 1990). The family includes E-cadherinluvomorulin (Nagafuchi et al., 1967; Ringwald et al., 1987) N-cadherin/A-CAM (Hattaet al., 1988) P-cadherin (Nose et al., 1987) and L-CAM (Gallin et al., 1987) and it was recently found that desmosomal glycoproteins are also members of this family, although their overall structure is slightly different from that of the original cadherins (Koch et al., 1990; Holton et al., 1990). Cadherins are essential not only for physical cell-cell associations but also for selective cell adhesion; each member of the family shows a homophilic binding property, and therefore cells are able to adhere only to the cells expressing the identical cadherins (Nose et al., 1988; Miyatani et al., 1989; Friedlander, et al., 1989). Up-regulation of cadherin expression affects morphogenesis of embryos by compacting cells (Detrick et al., 1990; Fujimori et al., 1990). Moreover, cadherins play a role in epithelioid morphology of nonepithelial cells (Mege et al.,