Fig. 7. Analysis of stable transfectant MDCK cells expressing InsP₃R-1-EGFP. (A) Western blot: 50 µg of protein of cell lysates from parental MDCK, clone 10B and clone 1E were loaded on a gradient 4-10% polyacrylamide minigel (BioRad MiniPROTEAN system). The gradient minigel allowed both the small molecular weight of the GFP and the high molecular weight of the InsP₃R to be visualized on the same blot. After transfer, western blotting was performed using antibodies against InsP₃R-1, GFP and N-terminus InsP₃R-3, respectively. (B) Localization of InsP₃R-3 and InsP₃R-1-EGFP in MDCK clone 10B, which stably expressed InsP₃R-1-EGFP. The tagged InsP₃R-1 is expressed by most cells of this clone, except a few (arrows), whereas all cells express InsP₃R-3. Bar, 10 µm.