Chemical gating of gap junction channels.
Chemical gating of gap junction channels is a complex phenomenon that may involve intra- and intermolecular interactions among connexin domains and a cytosolic molecule (calmodulin?) that may function as channel plug. This article focuses on the methodology we have employed for studying the molecular basis of chemical gating by lowered cytosolic pH. Our approach has combined molecular genetics and biophysics, using exposure to 100% CO(2) for assaying chemical gating efficiency. Chimeras of connexin 32 (Cx32) and connexin 38 (Cx38) and Cx32 mutants modified at residues of the cytoplasmic loop, the initial C-terminus domain, or both have been expressed in Xenopus oocytes, and channel expression and gating have been tested electrophysiologically by double voltage clamp. In addition, various channel forms, including homotypic, heterotypic, and heteromeric channel combinations, have been evaluated for chemical gating sensitivity.
Peracchia
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Department of Pharmacology and Physiology, University of Rochester, School of Medicine and Dentistry, 601 Elmwood Avenue, Rochester, New York 14642-8711, USA. CAMILLO_PERACCHIA@URMC.ROCHESTER.EDU
Wang
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Peracchia
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D000818:Animals; D018929:Cell Culture Techniques / Q000379:methods; D002478:Cells, Cultured; D017630:Connexins / Q000235:genetics / Q000502:physiology*; D005260:Female; D017629:Gap Junctions / Q000502:physiology*; D015640:Ion Channel Gating / Q000502:physiology*; D009865:Oocytes / Q000502:physiology*; D018408:Patch-Clamp Techniques; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D014982:Xenopus laevis; D000097002:Gap Junction beta-1 Protein
D017630:Connexins; D011993:Recombinant Fusion Proteins; D000097002:Gap Junction beta-1 Protein; C102630:connexin 38