Differential expression of Kv4 pore-forming and KChIP auxiliary subunits in rat uterus during pregnancy.
Differential expression of Kv4 pore-forming and KChIP auxiliary subunits in rat uterus during pregnancy.
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妊娠期大鼠子宫中 Kv4 成孔和 KChIP 辅助亚基的差异表达。
DOI：
10.1152/ajpendo.00250.2004
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发表时间：
2005
期刊：
影响因子：
--
通讯作者：
Takimoto,Koichi
中科院分区：
文献类型：
--
作者：
Suzuki,Takahiro;Takimoto,Koichi
电压门控K+(kv)通道表达的调控可能参与了妊娠期子宫平滑肌细胞收缩性的调控。这些通道的功能表达不仅受成孔亚基水平的控制，而且还需要它们与辅助亚基的关联。具体来说，快速灭活钾电流在子宫肌瘤细胞中很突出，可能由Kv4成孔和KChIP辅助亚基组成的复合物携带。为了确定通道复合物的分子特性及其在妊娠期间的变化，我们检测了这些亚基在大鼠子宫中的表达和定位。RT-PCR分析显示，大鼠子宫表达了Kv4的三个孔形成亚基和KChIP2和4辅助亚基。这些亚基mrna的表达在怀孕期间是动态和区域选择性调节的。在语料库中，Kv4。2 mRNA水平在分娩前升高，而Kv4。1和Kv4。3 mrna在怀孕期间减少。KChIP2 mRNA水平在妊娠后期也明显升高。在子宫颈，所有三种成孔mrna和两种辅助亚基mrna的表达在妊娠后期增加。免疫沉淀和免疫印迹分析显示Kv4。2-KChIP2复合物在妊娠后期子宫中显著存在。Kv4。2和kchip2免疫反应蛋白均存在于圆形和纵向肌细胞中。最后,Kv4。2和KChIP2 mRNA水平在单侧妊娠大鼠和非妊娠大鼠体内相似地升高。这些结果表明，扩散因子协调妊娠相关的子宫肌层Kv4-KChIP通道复合物分子组成的变化。
Regulation of voltage-gated K+(K v) channel expression may be involved in controlling contractility of uterine smooth muscle cells during pregnancy. Functional expression of these channels is not only controlled by the levels of pore-forming subunits, but requires their association with auxiliary subunits. Specifically, rapidly inactivating K v current is prominent in myometrial cells and may be carried by complexes consisting of Kv4 pore-forming and KChIP auxiliary subunits. To determine the molecular identity of the channel complexes and their changes during pregnancy, we examined the expression and localization of these subunits in rat uterus. RT-PCR analysis revealed that rat uterus expressed all three Kv4 pore-forming subunits and KChIP2 and-4 auxiliary subunits. The expression of mRNAs for these subunits was dynamically and region selectively regulated during pregnancy. In the corpus, Kv4. 2 mRNA level increased before parturition, whereas the expression of Kv4. 1 and Kv4. 3 mRNAs decreased during pregnancy. A marked increase in KChIP2 mRNA level was also seen at late gestation. In the cervix, the expression of all three pore-forming and two auxiliary subunit mRNAs increased at late gestation. Immunoprecipitaton followed by immunoblot analysis indicated that Kv4. 2-KChIP2 complexes were significant in uterus at late pregnancy. Kv4. 2-and KChIP2-immunoreactive proteins were present in both circular and longitudinal myometrial cells. Finally, Kv4. 2 and KChIP2 mRNA levels were similarly elevated in pregnant and nonpregnant corpora of one side-conceived rats. These results suggest that diffusible factors coordinate the pregnancy-associated changes in molecular compositions of myometrial Kv4-KChIP channel complexes.