Bedner Peter, Niessen Heiner, Odermatt Benjamin, Kretz Markus, Willecke Klaus, Harz Hartmann
Institut für Genetik, Abteilung Molekulargenetik, Universität Bonn, Römerstrasse 164, 53117 Bonn, Germany.
J Biol Chem. 2006 Mar 10;281(10):6673-81. doi: 10.1074/jbc.M511235200. Epub 2005 Dec 22.
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.
缝隙连接是细胞间通道，在脊椎动物中由连接蛋白形成，允许细胞内离子和小分子进行扩散交换。人类和小鼠基因组中至少有20种不同的连接蛋白基因以重叠的表达模式在特定细胞类型中表达。对于这种多样性的一种可能解释可能是生物重要分子（如第二信使分子）的不同通透性。我们最近证明，环核苷酸门控通道可用于量化缝隙连接介导的环磷酸腺苷（cAMP）扩散。使用这种方法，我们比较了由连接蛋白26、32、36、43、45或47蛋白组成的缝隙连接通道对第二信使cAMP的相对通透性。在这里，我们表明cAMP通过所研究的连接蛋白通道渗透的效率相差高达30倍。我们的结果表明，不同细胞类型中的细胞间cAMP信号传导可能受连接蛋白表达模式的影响。
