Fig. 5. Expression of the ZO-1^7-444 fusion protein does not alter Cx43 abundance. (A) Transfected ROS cells were harvested and solubilized in 1% SDS and analyzed by immunoblotting. (B) Cells were incubated for 1 hour in PBS containing 100 µg/ml NHS-LC-biotin and solubilized in lysis buffer, and the biotinylated proteins were isolated with Neutravidin agarose (Pierce). The resins were extensively washed, and the bound material was analyzed by immunoblotting with Cx43 antiserum. The position of molecular mass markers is given in kDa.