Fig. 4. Effect of suprabasal 6ß4 on Smad2/3 translocation requires cell-cell contact. (A-J,L) Immunolocalization of Smad2/3; (K) immunolocalization of involucrin. K and L show the same field; the dashed line separates the stratified area (left side) containing involucrin-positive suprabasal cells from the area consisting of basal cells only (right side). (A-H) Suspended cells were attached to basal cells to form suprabasal layers, as shown schematically in Fig. 3B; (I,J) wt monolayers treated with Inv6ß4 keratinocyte-conditioned medium. Bar, 50 µm.