Selective permeability of different connexin channels to the second messenger cyclic AMP.
Gap junctions are intercellular conduits that are formed in vertebrates by connexin proteins and allow diffusion exchange of intracellular ions and small molecules. At least 20 different connexin genes in the human and mouse genome are cell-type specifically expressed with overlapping expression patterns. A possible explanation for this diversity could be different permeability of biologically important molecules, such as second messenger molecules. We have recently demonstrated that cyclic nucleotide-gated channels can be used to quantify gap junction-mediated diffusion of cyclic AMP. Using this method we have compared the relative permeability of gap junction channels composed of connexin 26, 32, 36, 43, 45, or 47 proteins toward the second messenger cAMP. Here we show that cAMP permeates through the investigated connexin channels with up to 30-fold different efficacy. Our results suggest that intercellular cAMP signaling in different cell types can be affected by the connexin expression pattern.
Bedner
Peter
P
Institut für Genetik, Abteilung Molekulargenetik, Universität Bonn, Römerstrasse 164, 53117 Bonn, Germany.
Niessen
Heiner
H
Odermatt
Benjamin
B
Kretz
Markus
M
Willecke
Klaus
K
Harz
Hartmann
H
D000818:Animals; D002460:Cell Line; D002463:Cell Membrane Permeability / Q000235:genetics / Q000502:physiology*; D018920:Coculture Techniques; D017630:Connexins / Q000378:metabolism*; D000242:Cyclic AMP / Q000031:analogs & derivatives / Q000378:metabolism*; D004058:Diffusion; D005455:Fluorescent Antibody Technique; D017629:Gap Junctions / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D051379:Mice; D051381:Rats; D015290:Second Messenger Systems / Q000235:genetics / Q000502:physiology*; D014162:Transfection
D017630:Connexins; D000242:Cyclic AMP