Connexin37 forms high conductance gap junction channels with subconductance state activity and selective dye and ionic permeabilities

摘要: Gap junctions are thought to mediate the direct intercellular coupling of adjacent cells by open-closed gating an aqueous pore permeable ions and molecules up 1 kDa or 10–14 A in diameter. We symmetrically altered ionic composition asymmetrically added 6-carboxyfluorescein (6-CF, M(r) = 376), a fluorescent tracer, pairs connexin37-transfected mouse neuro2A examine dye permeability human connexin37 channels. demonstrate that 300-pS channel formed has effective relative anion/cation ratio 0.43, directly converts at least one intermediate (63 pS) subconductance state, 6-CF transfer is accompanied 24% decrease unitary conductance. These observations favor new interpretation gap junction consistent with ion-channel interactions electrostatic charge effects common more conventional multistate ion results have distinct implications about different forms signaling (cationic, ionic, and/or biochemical) can occur depending on expression conformation connexin proteins.