Fig. 1. (A) Schematic of Par6B domain structure. (B) Inhibition of tight junction assembly by the GBD of Par6B. MDCK canine epithelial cells were transiently transfected with vectors that express myc-tagged versions of the Par6B GBD (semi-CRIB + PDZ; residues 126–253), the isolated PDZ domain (140–256) or the semi-CRIB motif alone (102–186). The cells were incubated in a calcium-free medium overnight to disrupt cell–cell contacts, then returned to normal DMEM/serum for 6 h to permit junction re-assembly. They were then washed and stained for the tight junction marker, Z0-1 (green), the myc tag (red) and DNA (blue).