Species-specific voltage-gating properties of connexin-45 junctions expressed in Xenopus oocytes.

摘要: Gap junctions composed of connexin-45 (Cx45) homologs from four species, zebrafish, chicken, mouse, and human, were expressed in pairs Xenopus oocytes. The macroscopic conductance (gj) all Cx45 was modulated by transjunctional voltage (Vj) the inside-outside (Vm), modulation species specific. Although their gating characteristics varied sensitivity kinetics, shared 1) maximum at Vj = 0 symmetrical gj reduction response to positive negative low amplitude, with little residual conductance; 2) increases simultaneous depolarization paired cells. formation hybrid channels, comprising hemichannels different allowed us infer that two separate gates exist, one each hemichannel, hemichannel is closed negativity on its cytoplasmic side. Interestingly, Vm dependence channels also suggests presence series, gate hemichannel. Thus provides evidence independent reacting through specific sensors operating mechanisms, properties have evolved divergently among species.