Figure 7.

Involvement of Crk, Mbc, and ELMO in JNK activation downstream of PVR. (A) Genetic interaction of Crk and mbc with Pvr. The severity of the TC defect caused by pnr>Pvr-IR was increased by heterozygosity for loss-of-function alleles of Crk and mbc and Crk RNAi. Classes I–III correspond to phenotypes shown in Figure 1F–H, respectively. (B) S2 cell lines expressing Mbc-HA or ELMO-Myc (see Figure 5A) under the control of the metallothionein promoter were established. Cells were serum-starved overnight, and then transgenic proteins were induced for 5 h by the addition of CuSO₄ to the medium. Compared with the vector-transfected (mock) cells (lane 3), S2 cells expressing Mbc-HA (lane 1) or ELMO-Myc (lane 2) have elevated JNK activity. (C) The PDGFRα/PVR-Myc cell line was incubated in the absence (NT, lanes 1 and 2) or presence (lanes 3–5) of dsRNA products directed against Crk (lane 3), mbc (lane 4), or ELMO (lane 5). Cells were grown as described in the legend of Figure 2B. Subsequently, the cells were either left untreated (lane 1) or treated (lanes 2–5) with 100 ng/ml PDGF-BB for 20 min. Cellular extracts were prepared and subjected to Western analyses using anti-p-JNK, anti-JNK1, anti-Crk, anti-Mbc, anti-ELMO, anti-pTyr, and anti-Myc antibodies.