Differential function of N-cadherin and cadherin-7 in the control of embryonic cell motility

Similar amounts of N-cadherin and cadherin-7, the prototypes of type I and type II cadherin, induced cell-cell adhesion in murine sarcoma 180 transfec tants, Ncad-1 and cad7-29, respectively. However, in the initial phase of a ggregation, Ncad-1 cells aggregated more rapidly than cad7-29 cells. Isolat ed Ncad-1 and cad7-29 cells adhered and spread in a similar manner on fibro nectin (FN), whereas aggregated cad7-29 cells were more motile and disperse d than aggregated Ncad-1 cells. cad7-29 cells established transient contact s with their neighbors which were stabilized if FN-cell interactions were p erturbed. In contrast, Ncad-1 cells remained in close contact when they mig rated on FN. Both beta-catenin and cadherin were more rapidly downregulated in cad7-29 than in Ncad-1 cells treated with cycloheximide, suggesting a h igher turnover rate for cadherin-7-mediated cell-cell contacts than for tho se mediated by N-cadherin. The extent of FN-dependent focal adhesion kinase phosphorylation was much lower if the cells had initiated N-cadherin-media ted rather than cadherin-7-mediated cell adhesion before plating. On grafti ng into the embryo, Ncad-1 cells did not migrate and remained at or close t o the graft site, even after 48 h, whereas grafted cad7-29 cells dispersed efficiently into embryonic structures, Thus, the adhesive phenotype of cadh erin-7-expressing cells is regulated by the nature of the extracellular mat rix environment which also controls the migratory behavior of the cells. In addition, adhesions mediated by different cadherins differentially regulat e FN-dependent signaling, The transient contacts specifically observed in c adherin-7-expressing cells may also be important in the control of cell mot ility.