Figure 4

ERMs and Rac1 activity are involved in ICAM-2-dependent NCad recruitment and cell-cell contact. A- Rac1 activity in MCEC cell lines, as measured by the GST-PAK pull-down assay. (a) Representative Western blot analysis of Rac1 activity. Rac1-GTP pull-down with GST-PAK as well as total Rac1 were detected using mAb Cl23A8. (b) Quantification of Rac1 activity (Rac1-GTP/Total Rac1) in IC2 neg, IC2 FL, IC2 ΔERM, IC2 ΔTAIL cell lines. Error bars indicate mean ± s.e.m., n = 6. Statistical analysis (t-test: *p < 0.05, **p < 0.005). B- Effect of DN and CA Rac1 on the morphology and the distribution of NCad in the IC2 neg and IC2 FL lines. IC2 neg or IC2 FL were transfected with pEGFP control (a-d and m-p), pEGFP-V12 Rac1 (e-h and q-t) or pEGFP-V12-N17 Rac1 (i-l and u-x). Cells were co-stained for ICAM-2 and NCad. ICAM-2 was stained using the mAb 3C4 anti-mouse ICAM-2 followed by anti-rat AlexaFluor488 (pseudo colored Red). NCad was stained using mAb Cl32 anti-NCad followed by anti-mouse AlexaFluor555 (pseudo colored Blue). Bar = 25 μm.