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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-2
5, JAM-3
5). 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.