FIG. 1.

Schematic representation of the mixed-culture coimmunoprecipitation assay. Two clones of A-431 cells expressing E-cadherin, tagged with either myc or Flag epitopes (AEcM and AEcF cells, respectively), were mixed and cocultivated overnight. Both tagged E-cadherin forms lack the epitope for the anti-E-cadherin antibody, C20820, in the intracellular segment of endogenous cadherin (indicated by an open box). The extracellular E-cadherin region consists of five repetitive ectodomains, which are indicated by numbers. Anti-myc immunoprecipitation of these cocultures results in coimmunoprecipitation of wild-type E-cadherin (wt) which can be derived from either Ec1M-E-cadherin adhesive (box 1), or Ec1M-E-cadherin lateral (box 2) dimers. In contrast, Ec1F can be derived only from adhesive Ec1M-Ec1F dimers (box 3).