A, Western blot analysis (anti-His6) of wild-type (WT; CNGA1 and CNGB1) and mutant (Y→F; CNGA1Y498F and CNGB1Y1097F) channel subunits. Before homogenization, oocytes expressing heteromeric CNG channels and non-injected oocytes (Control) were pretreated with pervanadate (PV), a PTP inhibitor, or lavendustin A (LavA), a PTK inhibitor. Molecular mass markers (in kDa) are shown on the right. B, autoradiograms of wild-type (CNGA1 and CNGB1) and mutant (CNGA1Y498F and CNGB1Y1097F) subunits.