Identification and localization of E- and N-cadherin–containing AJ structures connecting cells of primary cultures of human hepatocytes and hepatocellular carcinoma cells of line PLC. (A–C′′) Laser-scanning immunofluorescence microscopy of E–N-cadherin heterodimer–containing AJs in primary human hepatocytes (A and B) or hepatocellular carcinoma cells of the line PLC (C), freshly replated and allowed to reassociate in small colonies, after reaction with antibodies against N (A and A’’, red; C and C′′, green)- and E (A′ and A′′, green; C′ and C′′, red)-cadherin, showing cell–cell contacts with extensive colocalization (yellow merge color; A′′, B, and C′′) in small punctate AJs or in extended linear structures. Note that some colonies show cell–cell contact regions positive for both cadherins and presenting extensive colocalization (A–B; the right hand four-cell colony in C–C′′), whereas other—often directly adjacent—cell colonies present junctions that are positive only for one of the two cadherins (here, N-cadherin on the left of C–C′′). Note also the additional occurrence of small whisker- or dot-shaped structures at the cell surface, which are N- or E-cadherin positive or show already a merged color (yellow). Bars: (A′′ and B) 10 µm; (C′′) 20 µm.