Altered K+ channel subunit composition following hormone induction of Kv1.5 gene expression.
Altered K+ channel subunit composition following hormone induction of Kv1.5 gene expression.
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激素诱导 Kv1.5 基因表达后，K 通道亚基组成发生改变。
DOI：
10.1021/bi961290s
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发表时间：
1996
期刊：
影响因子：
--
通讯作者：
Levitan,ES
中科院分区：
文献类型：
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作者：
Takimoto,K;Levitan,ES
不同的电压门控K+通道是由通道α亚基的四聚化产生的，可以由多个基因编码。在gh3垂体细胞中，Kv1.4和Kv1.5亚基基因组成性表达，地塞米松选择性上调后者基因的表达。在这里，我们使用亚单位特异性抗体来确定Kv1.5基因诱导对同质和异质通道表达的影响。在对照细胞中，几乎所有可检测到的Kv1.4蛋白都与Kv1.5蛋白相关，而只有约30%的Kv1.5蛋白以Kv1.4/Kv1.5异质通道的形式存在。地塞米松处理使Kv1.5同质通道的表达增加了一倍，但仅适度上调Kv1.4/Kv1.5异质复合物的表达。类固醇处理同样增加了细胞和细胞表面的Kv1.5蛋白总量，而不影响任何部分的Kv1.4蛋白。因此，激素诱导的一个K+通道亚基基因对细胞表面同质通道和异质通道的表达有不同的影响，从而导致兴奋性的特异性改变。
Diverse voltage-gated K+channels are produced by tetramerization of channel α subunits that can be encoded by multiple genes. In GH3pituitary cells, the Kv1.4 and Kv1.5 subunit genes are constitutively expressed, and dexamethasone selectively up-regulates expression of the latter gene. Here we use subunit-specific antibodies to determine the effect of Kv1.5 gene induction on expression of homomeric and heteromeric channels. In control cells, almost all detectable Kv1.4 proteins are associated with Kv1.5 protein, whereas only ∼30% Kv1.5 protein is present as Kv1.4/Kv1.5 heteromeric channels. Dexamethasone treatment doubled expression of Kv1.5 homomeric channels but only modestly up-regulated Kv1.4/Kv1.5 heteromeric complexes. The steroid treatment similarly increased total cellular and cell surface Kv1.5 protein without affecting Kv1.4 proteins in either fraction. Thus, hormone induction of one K+channel subunit gene differentially influences expression of cell surface homomeric and heteromeric channels leading to specific alteration of excitability.