Figure 6

Smad1-dependent nuclear translocation of Smad1, HsN3 and Az in response to BMP type I receptor activation. A-C. Smad1 and HsN3 are both rapidly translocated from the cytoplasm to the nucleus in response to BMP2. COS cells were transiently transfected with Smad1, ALK3 and BMPRII and were either not treated (A), or treated with BMP2 for 30 mins (B), and 60 mins (C). Smad1 (red) and HsN3 (green) signals at each time point were detected and their co-localization shown by overlaying HsN3 signals in panel "1" with Smad1 signals in panel "2" to yield panel "3". D. HsN3 nuclear translocation is dependent upon the coexpression of Smad1 and the activation of the BMP type I receptor. COS cells were transfected with the indicated plasmids. HsN3 was detected by anti-Flag monoclonal antibody and FITC conjugated anti-mouse secondary antibody. E. Az is also translocated to the nucleus in response to the activation of BMP type I receptor in a Smad1-dependent fashion. COS cells were transfected with the indicated plasmids and stained with anti-Flag monoclonal antibody and FITC conjugated anti-mouse secondary antibody. To maximize the details of intracellular localization of each protein, each panel only shows the single cell-image that represents the localization patterns in more than 80% transfected cells.