Cloning and functional characterization of inward-rectifying potassium (Kir) channels from Malpighian tubules of the mosquito Aedes aegypti.
Cloning and functional characterization of inward-rectifying potassium (Kir) channels from Malpighian tubules of the mosquito Aedes aegypti.
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DOI：
10.1016/j.ibmb.2012.09.009
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发表时间：
2013-01
影响因子：
3.8
通讯作者：
Beyenbach KW
中科院分区：
文献类型：
--
作者：
Piermarini PM;Rouhier MF;Schepel M;Kosse C;Beyenbach KW
内向整流 K+ (Kir) 通道在多种脊椎动物细胞/组织中发挥着重要的生理作用，包括神经和肌肉膜电位的调节，以及渗透调节上皮细胞（如肾脏和鳃）中离子的跨上皮转运。 Kir 通道在昆虫中是否发挥类似的生理作用仍有待确定。在本研究中，我们试图 1) 克隆埃及伊蚊肾（马氏）小管中表达的 Kir 通道亚基的 cDNA，2) 表征克隆的 Kir 亚基在非洲爪蟾卵母细胞中异源表达时的电生理特性。在这里，我们发现三个 Kir 亚基在马尔皮基伊蚊小管中大量表达（AeKir1、AeKir2B 和 AeKir3）；它们的每一个全长 cDNA 均被克隆。非洲爪蟾卵母细胞中 AeKir1 或 AeKir2B 亚基的异源表达会引发内向整流 K+ 电流，该电流被钡阻断。相对于表达 AeKir2B 的卵母细胞，表达 AeKir1 的卵母细胞 1) 产生更大的宏观电流，2) 表现出细胞外 Na+ 对其传导特性的调节。对爪蟾卵母细胞中 AeKir3 亚基进行功能表征的尝试未成功。最后，我们发现在分离的伊蚊马尔皮基小管中，主细胞基底外侧膜的阳离子通透性序列（Tl+>K+>Rb+>）与功能性Kir通道的存在一致。我们得出的结论是，在伊蚊马尔皮基小管中，Kir 通道有助于大部分钡敏感的 K+ 跨上皮转运。
Inward-rectifying K+ (Kir) channels play critical physiological roles in a variety of vertebrate cells/tissues, including the regulation of membrane potential in nerve and muscle, and the transepithelial transport of ions in osmoregulatory epithelia, such as kidneys and gills. It remains to be determined whether Kir channels play similar physiological roles in insects. In the present study, we sought to 1) clone the cDNAs of Kir channel subunits expressed in the renal (Malpighian) tubules of the mosquito Aedes aegypti, and 2) characterize the electrophysiological properties of the cloned Kir subunits when expressed heterologously in oocytes of Xenopus laevis. Here, we reveal that three Kir subunits are expressed abundantly in Aedes Malpighian tubules (AeKir1, AeKir2B, and AeKir3); each of their full-length cDNAs was cloned. Heterologous expression of the AeKir1 or the AeKir2B subunits in Xenopus oocytes elicits inward-rectifying K+ currents that are blocked by barium. Relative to the AeKir2B-expressing oocytes, the AeKir1-expressing oocytes 1) produce larger macroscopic currents, and 2) exhibit a modulation of their conductive properties by extracellular Na+. Attempts to functionally characterize the AeKir3 subunit in Xenopus oocytes were unsuccessful. Lastly, we show that in isolated Aedes Malpighian tubules, the cation permeability sequence of the basolateral membrane of principal cells (Tl+ > K+ > Rb+ > ) is consistent with the presence of functional Kir channels. We conclude that in Aedes Malpighian tubules, Kir channels contribute to the majority of the barium-sensitive transepithelial transport of K+.
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影响因子：
64.8
作者：
Hansen, Scott B.;Tao, Xiao;MacKinnon, Roderick
通讯作者：
MacKinnon, Roderick
影响因子：
2.8
作者：
Beyenbach, Klaus W.;Baumgart, Sabine;Zhang, Sheng
通讯作者：
Zhang, Sheng
影响因子：
5.5
作者：
Abbas, Leila;Hajihashemi, Saeed;White, Stanley J.
通讯作者：
White, Stanley J.
影响因子：
2.2
作者：
Beyenbach, KW;Masia, R
通讯作者：
Masia, R
影响因子：
5.5
作者：
Ho, IHM;Murrell-Lagnado, RD
通讯作者：
Murrell-Lagnado, RD