异型缝隙连接通道和磷酸化对心脏细胞通讯的调节作用

Regulation of Cardiac Gap Junctional Permeability by Heteromeric Gap Junction Channels and Phosphorylation

为了检测缝隙连接蛋白 (Cx) 4 3和Cx4 5组成的多种异型缝隙连接通道和磷酸化对缝隙连接 (GJ)里细胞通讯的调节作用 ,将转染了编码为Cx4 3或Cx4 5的DNA后的Hela细胞放置在一起共同培养组成双侧和单侧异型GJ通道。显微注射荧光素黄 (LY)后 ,利用紫外光检测经 2 0 0nmol/L十四 (烷 )酰佛波醇乙酸酯 (TPA)处理前后由Cx4 3和Cx4 5所组成的多种异型GJ通道对荧光染料的偶联率。结果 :在不同的GJ中 ,同型GJ通道Cx4 3(HoCx4 3)偶联率最高。单侧异型GJ通道Cx4 3(MH4 3)和单侧异型GJ通道Cx4 5 (MH4 5 )的偶联率较之相关的HoCx4 3和同型GJ通道Cx4 5 (HoCx4 5 )低。从Cx4 5侧注入荧光染料的MH4 5偶联率较之从Cx4 3/ 4 5侧注射的MH4 5、双侧异型GJ通道Cx4 3/4 5 (BH4 3/ 4 5 )和HoCx4 5等的偶联率都低。TPA处理后HOCx4 3的偶联率降低 ,而当Cx4 3和Cx4 5组合成异型BH4 3/4 5和MH4 3通道其偶联率下降更显著。结论 :Cx4 3和Cx4 5共同表达可构成BH4 3/ 4 5、MH4 3和MH4 5等通道 ,而这些异型GJ通道可降低细胞间通信和对磷酸化的敏感性。有关MH4 5通道 ,其偶联率大小决定于荧光染料的注射方向 ,此可能与心律失常再折返的解剖学的机制有关。

To determine the docking effects of the heteromultimeric combination of Cx43 and Cx45 and the phosphorylation on the permeability properties of their channels.The HeLa cells were transfected DNA encoding Cx43 or Cx45 colocalized to form bi-heteromeric and mono-heteromeric channels.The dye permeability of various combinations of Cx43 and Cx45 under epifluorescent illumination before and after 200 nmol/L 12-0-tetradecanoylphorbol-13-acetae (TPA) treatment was determined by microinjection with Lucifer yellow (LY).Results:Homotypic Cx43 (HoCx43) channels were the best coupled in the different combination of connexins.The permeability of mono-heteromeric Cx43-Cx43/45 (MH43) and mono-heteromeric Cx45-Cx43/45 (MH45) channels were less than that in HoCx43 and Homotypic Cx45 (HoCx45) channels.The permeability of MH45 injected from the side of Cx45 was least compared with the channels of MH45 injected from the side of Cx43/45,bi-heteromeric Cx43/45 (BH43/45) and HoCx45.After TPA treatment,the coupling ratio of HoCx43 was reduced and this reduction in coupling was accentuate for channels with bi-heteromeric or mono-heteromeric connexonx.Conclusion:These data strongly suggest that co-expressed Cx43 and Cx45 can form bi-heteromenic and mono-heteromeric channels, which lead low gap junctional communication and insensitivity to phosphorylation.The permeability of mono-heteromeric channels depending on the direction of dye injection might relate the anatomical reentry of arrhythmia.