Connexin43 with a cytoplasmic loop deletion inhibits the function of several connexins.
Connexins (Cx) form gap junction channels mediating direct intercellular communication. To study the role of amino acids within the cytoplasmic loop, we produced a recombinant adenovirus containing Cx43 with a deletion of amino acids 130-136 (Cx43del(130-136)). Cx43del(130-136) expressed alone in HeLa cells localized within the cytoplasm and did not allow transfer of ions, neurobiotin or Lucifer yellow. When co-expressed with wild type Cx43, Cx43del(130-136) blocked electrical coupling and transfer of neurobiotin or Lucifer yellow. Cx43del(130-136) and Cx43 co-localized by immunofluorescence and were co-purified from Triton X-100-solubilized cell extracts. Intercellular transfer mediated by Cx37 and Cx45 (but not Cx26 or Cx40) was inhibited when co-expressed with Cx43del(130-136). Cx43del(130-136) co-localized with Cx37, Cx40, or Cx45, but not Cx26. These data suggest that Cx43del(130-136) produces connexin-specific inhibition of intercellular communication through formation of heteromeric connexons that are non-functional and/or retained in the cytoplasm.
Department of Pediatrics, Section of Hematology/Oncology and Stem Cell Transplantation, University of Chicago, Chicago, IL, USA.
Min
M
Wang
Agustín D
AD
Martínez
Viviana M
VM
Berthoud
Kyung H
KH
Seul
Joanna
J
Gemel
Virginijus
V
Valiunas
Sindhu
S
Kumari
Peter R
PR
Brink
Eric C
EC
Beyer
D019943:Amino Acid Substitution; D002450:Cell Communication / Q000502:physiology*; D000072259:Connexin 26; D018031:Connexin 43 / Q000235:genetics / Q000378:metabolism*; D017630:Connexins / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D016297:Mutagenesis, Site-Directed; D021381:Protein Transport / Q000502:physiology*; D011994:Recombinant Proteins / Q000378:metabolism
D018031:Connexin 43; D017630:Connexins; C500216:GJA1 protein, human; C000607042:GJB2 protein, human; D011994:Recombinant Proteins; D000072259:Connexin 26