Figure 7.

LAD-2 can enhance coupling of MAB-20 to PLX-2 as determined by Co-IP assays performed using anti-Myc antibodies. (A) LAD-2 interacts with MAB-20 and PLX-2 independently. Co-IP assays were performed on lysates of HEK293T cells coexpressing LAD-2 with Myc∷MAB-20 (lane 1), Myc∷PLX-2 (lane 2), and a control Myc vector (lane 3). The top two panels are Western blot analyses of the respective proteins in each lysate and the bottom panels are the Western blot of the Co-IP results. The asterisk points to a 170-kD band seen in lane 1 that may correspond to putative MAB-20 dimers. The bracketed bands in lane 2 are PLX-2 products; the lower band is a putative degradation product of PLX-2. (B) LAD-2 does not interact with SLT-1 or SAX-3. Co-IP assays were performed on cells coexpressing LAD-2 with Myc∷PLX-2 (lanes 1 and 3), Myc∷SLT-1 (lane 2), and Myc∷SAX-3 (lane 4). The top shows LAD-2 in each lysate as assayed by Western blotting; the bottom shows the Western blot analyses of the Co-IP results showing LAD-2 coimmunoprecipitates with PLX-2 (bracketed bands in lane 1 and 3) but not SLT-1 or SAX-3. (C) LAD-2 but not SAX-3 can enhance a weak interaction between mab-20 and PLX-2 as determined by Co-IP assays performed on cells coexpressing FLAG∷MAB-20 together with Myc∷PLX-2 and LAD-2 (lane 1), Myc∷PLX-2 and FLAG∷SAX-3 (lane 2), Myc∷PLX-2 (lane 3), or a control Myc vector (lane 4). Western blot analyses of the respective proteins in each lysate and Co-IP results are shown. Note that the low levels of FLAG∷MAB-20 CoIPs with Myc∷PLX-2 (lane 3) increases dramatically in the presence of LAD-2 (lane 1) but remains unchanged in the presence of SAX-3 (lane 2). (D) MAB-20 can form homodimers. Co-IP assays were performed on cells coexpressing FLAG∷MAB-20 with Myc∷MAB-20 (lane 1) and control Myc vector (lane 2). The top two panels are Western blot analyses of the respective proteins expressed in each lysate; the bottom shows Western blot analyses of the Co-IP results.