Modulation of the Kv1.3 potassium channel by receptor tyrosine kinases
Modulation of the Kv1.3 potassium channel by receptor tyrosine kinases
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DOI：
10.1085/jgp.110.5.601
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发表时间：
1997-11-01
影响因子：
3.8
通讯作者：
Levitan, IB
中科院分区：
文献类型：
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作者：
Bowlby, MR;Fadool, DA;Levitan, IB
电压依赖性钾通道Kv1.3受表皮生长因子受体（EGFr）和胰岛素受体酪氨酸激酶调节。当EGFr和Kv1.3在HEK 293细胞中共表达时，在贴片记录期间用EGF急性处理细胞可以在数十分钟内抑制Kv1.3电流。这种效应似乎是由于通道的酪氨酸磷酸化，因为它被酪氨酸激酶抑制剂erbstatin阻断，或被通道氨基酸位置479处的酪氨酸突变为苯丙氨酸阻断。以前的工作表明，当Kv1.3与EGFr共表达时，Kv1.3的酪氨酸磷酸化水平大幅增加。用EGF预处理EGFr和Kv1.3共转染的细胞也可使Kv1.3峰电流降低。此外，用EGFr配体结合结构域（α-EGFr）的抗体预处理共转染细胞，其阻断受体二聚化和酪氨酸激酶活化，阻断EGFr介导的Kv1.3电流抑制。在斑贴记录过程中，胰岛素处理也会在几十分钟后引起Kv1.3电流的抑制，而预处理18 h则几乎完全抑制电流。除了抑制峰值Kv1.3电流外，EGF处理还加速了C型失活，而用α-EGFr预处理则减缓了C型失活。相反，胰岛素不影响C型失活动力学。突变分析表明，EGF诱导的失活率的调制发生的机制不同于EGF诱导的峰值电流的降低。因此，受体酪氨酸激酶差异调节电压依赖性钾通道的电流大小和动力学。
The voltage-dependent potassium channel, Kv1.3, is modulated by the epidermal growth factor receptor (EGFr) and the insulin receptor tyrosine kinases. When the EGFr and Kv1.3 are coexpressed in HEK 293 cells, acute treatment of the cells with EGF during a patch recording can suppress the Kv1.3 current within tens of minutes. This effect appears to be due to tyrosine phosphorylation of the channel, as it is blocked by treatment with the tyrosine kinase inhibitor erbstatin, or by mutation of the tyrosine at channel amino acid position 479 to phenylalanine. Previous work has shown that there is a large increase in the tyrosine phosphorylation of Kv1.3 when it is coexpressed with the EGFr. Pretreatment of EGFr and Kv1.3 cotransfected cells with EGF before patch recording also results in a decrease in peak Kv1.3 current. Furthermore, pretreatment of cotransfected cells with an antibody to the EGFr ligand binding domain (alpha-EGFr),which blocks receptor dimerization and tyrosine kinase activation, blocks the EGFr-mediated suppression of Kv1.3 current. Insulin treatment during patch recording also causes an inhibition of Kv1.3 current after tens of minutes, while pretreatment for 18 h produces almost total suppression of current. In addition to depressing peak Kv1.3 current, EGF treatment produces a speeding of C-type inactivation, while pretreatment with the alpha-EGFr slows C-type inactivation. In contrast, insulin does not influence C-type inactivation kinetics. Mutational analysis indicates that the EGF-induced modulation of the inactivation rate occurs by a mechanism different from that of the EGF-induced decrease in peak current. Thus, receptor tyrosine kinases differentially modulate the current magnitude and kinetics of a voltage-dependent potassium channel.