Connexin43 and connexin45 form heteromeric gap junction channels in which individual components determine permeability and regulation (original) (raw)

Two gap junction proteins, connexin43 (Cx43) and connexin45 (Cx45), are coexpressed in many cardiac and other cells. Homomeric channels formed by these proteins differ in unitary conductance, permeability, and regulation. We sought to determine the ability of Cx43 and Cx45 to oligomerize with each other to form heteromeric gap junction channels and to determine the functional and regulatory properties of these heteromeric channels. HeLa cells were transfected with Cx45 or (His)(6)-tagged Cx43 or sequentially transfected with both connexins. Immunoblots verified production of the transfected connexins, and immunofluorescence demonstrated that they were colocalized in the HeLa-Cx43(His)(6)/Cx45 cells. Connexons were solubilized from HeLa-Cx43(His)(6)/Cx45 cells by using Triton X-100 and were applied to a Ni(2+)-NTA column, which binds the His(6) sequence. Cx45 was coeluted from the column with Cx43(His)(6), demonstrating that some hemichannels contain both connexins. Single-channel re...