Fig. 3. TPA-treated NRK cells show increased phosphorylation at S368 with no apparent shift in migration in SDS-PAGE. NRK cells were metabolically labeled with [³²P]orthophosphate and incubated in the presence (TPA) or absence (CON) of 50 ng/ml TPA for 30 minutes followed by immunoprecipitation of Cx43, blotting to nitrocellulose, and probing the blot first by autoradiography (³²P) and then using the anti-p368 antibody (-p368) and ultimately the N-terminal Cx43 antibody (-Cx43).