Molecular Dissection of Transjunctional Voltage Dependence in the Connexin-32 and Connexin-43 Junctions

摘要: Most gap junction channels are sensitive to the voltage difference between two cellular interiors, termed transjunctional (V(j)). In several junctions, conductance transitions induced by V(j) show more than one kinetic component. To elucidate structural basis of fast and slow components that characterize V(j )dependence connexin-32 (Cx32) connexin-43 (Cx43) we created deletions both connexins, where most carboxy-terminal (CT) domain was removed. The wild-type "tailless" mutants were expressed in paired Xenopus oocytes, macroscopic gating properties analyzed using dual clamp technique. Truncation CT Cx32 Cx43 abolished mechanism novel largely attributable gating. formation hybrid junctions comprising truncated hemichannels allowed us infer reside each hemichannel gates close at a negative on cytoplasmic side. Thus conclude V(j)-sensitive result action different mechanisms. They constitute separate structures molecules, being an integral part