Fig. 5. InsP₃R-3 in non-polarized ras transformed MDCK f3 cells. (A) f3 cells were plated at 10⁴ cells/cm² and examined for the localization of InsP₃R-3 and ZO-1 or E-cadherin after 3 and 10 days, respectively. (B) After 10 days in culture, cells were treated with the MEK inhibitor U0126 (25 µM): TER was measured and cells were double stained for InsP₃R-3 and ZO-1 or InsP₃R-3 and E-cadherin, at regular intervals during this treatment. After 1 day with U0126, ZO-1 was detected at the PM of most cells; E-cadherin was re-expressed in only a fraction of treated cells and in a small minority of those cells InsP₃R-3 was present not only in the cytoplasm, but also at the plasma membrane (*). Bar, 10 µm.