Formation of heteromeric gap junction channels by connexins 40 and 43 in vascular smooth muscle cells

Ding Sheng He, Jean X. Jiang, Steven M. Taffet, Janis M. Burt

Research output: Contribution to journalArticle

156 Scopus citations

Abstract

Connexin (Cx) 43 and Cx40 are coexpressed in several tissues, including cardiac atrial and ventricular myocytes and vascular smooth muscle. It has been shown that these Cxs form homomeric/homotypic channels with distinct permeability and gating properties but do not form functional homomeric/heterotypic channels. If these Cxs were to form heteromeric channels, they could display functional properties not well predicted by the homotactic forms. We assessed this possibility by using A7r5 cells, an embryonic rat aortic smooth muscle cell line that coexpresses Cxs 43 and 40. Connexons (hemichannels), which were isolated from these cells by density centrifugation and immunoprecipitated with antibody against Cx43, contained Cx40. Similarly, antibody against Cx40 coimmunoprecipitated Cx43 from the same connexon fraction but only Cx40 from Cx (monomer) fractions. These results indicate that heteromeric connexons are formed by these Cxs in the A7r5 cells. The gap junction channels formed in the A7r5 cells display many unitary conductances distinct from homomeric/homotypic Cx43 or Cx40 channels. Voltage-dependent gating parameters in the A7r5 cells are also quite variable compared with cells that express only Cx40 or Cx43. These data indicate that Cxs 43 and 40 form functional heteromeric channels with unique gating and conductance properties.

Original languageEnglish (US)
Pages (from-to)6495-6500
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume96
Issue number11
DOIs
StatePublished - May 25 1999

ASJC Scopus subject areas

  • General

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