Fig. 1. PAR-3 associates directly with JAM-2 and JAM-3. (A) Schematic view of PAR-3 and PAR-3 expression constructs used in this study. The three conserved regions (CR) are indicated by brackets. The aPKC-binding region (aa 712-936) is illustrated as grey bar encompassing CR3. The three PDZ domains are indicated. The expression constructs used in this study are schematically illustrated. (B) Full-length PAR-3 (PAR-3/1-1337) and a PAR-3 fragment comprising the three PDZ domains (PAR-3/PDZ1-3) were generated by in vitro transcription/translation in the presence of [³⁵S]-methionine and incubated with GST-fusion proteins containing the cytoplasmic domains of JAM-2, JAM-3 and JAM-1. To analyse the requirement of the PDZ domain binding motif, the C-terminal five aa residues of JAM-2 and JAM-3 were deleted (JAM-25, JAM-35). As control for unspecific binding GST alone was used (GST-). In the lane marked with `lysate', 7% of the transcription/translation reaction was loaded. PAR-3 binds to both JAM-2 and JAM-3 in a PDZ domain-dependent manner.