Lens Connexin Channels Have Differential Permeability to the Second Messenger cAMP.
Lens Connexin Channels Have Differential Permeability to the Second Messenger cAMP.
复制标题
晶状体连接蛋白通道对第二信使 cAMP 具有不同的渗透性。
DOI：
10.1167/iovs.19-27302
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发表时间：
2019
影响因子：
4.4
通讯作者：
White,ThomasW
中科院分区：
文献类型：
--
作者：
Valiunas,Virginijus;Brink,PeterR;White,ThomasW
目的：间隙连接通道表现出连接蛋白特异性的生物物理特性，包括较大溶质（如第二信使）的选择性细胞间通道。在这里，我们已经研究了环核苷酸的渗透性的透镜连接蛋白，这可能会影响事件，如上皮细胞的分裂和differentiation.Methods：我们比较了cAMP的渗透性通过通道组成的Cx43，Cx46，或Cx50使用同时测量的交界处电导和细胞间转移。对于cAMP检测，用cAMP传感器基因（来自海胆精子的环核苷酸调节通道（SpIH））转染受体细胞。通过膜片移液管将cAMP引入不表达SpIH的细胞对中。SpIH衍生的电流记录从另一个细胞对表达SpIH。cAMP的渗透性也直接可视化在转染的细胞中使用化学修饰的荧光形式的molecules.Results：观察到cAMP转移同型Cx43通道在很宽的范围内的交界电导。同型Cx46通道也传输cAMP，但与Cx43相比，通透性降低。与此相反，同型Cx50通道对cAMP的通透性极低，与Cx43或Cx46相比。结论：这些数据表明，Cx43和Cx46形成的通道导致足够量的cAMP在细胞间递送以激活环核苷酸调节的通道。数据还表明，大大降低的cAMP渗透性的Cx50通道可以发挥作用，在透镜的细胞分裂的调节。
Purpose: Gap junction channels exhibit connexin specific biophysical properties, including the selective intercellular passage of larger solutes, such as second messengers. Here, we have examined the cyclic nucleotide permeability of the lens connexins, which could influence events like epithelial cell division and differentiation.Methods: We compared the cAMP permeability through channels composed of Cx43, Cx46, or Cx50 using simultaneous measurements of junctional conductance and intercellular transfer. For cAMP detection, the recipient cells were transfected with a cAMP sensor gene, the cyclic nucleotide-modulated channel from sea urchin sperm (SpIH). cAMP was introduced via patch pipette into the cell of the pair that did not express SpIH. SpIH-derived currents were recorded from the other cell of a pair that expressed SpIH. cAMP permeability was also directly visualized in transfected cells using a chemically modified fluorescent form of the molecule.Results: cAMP transfer was observed for homotypic Cx43 channels over a wide range of junctional conductance. Homotypic Cx46 channels also transferred cAMP, but permeability was reduced compared with Cx43. In contrast, homotypic Cx50 channels exhibited extremely low permeability to cAMP, when compared with either Cx43, or Cx46.Conclusions: These data show that channels made from Cx43 and Cx46 result in the intercellular delivery of cAMP in sufficient quantity to activate cyclic nucleotide-modulated channels. The data also suggest that the greatly reduced cAMP permeability of Cx50 channels could play a role in the regulation of cell division in the lens.