Colocalization and coassembly of two human brain M-type potassium channel subunits that are mutated in epilepsy
Colocalization and coassembly of two human brain M-type potassium channel subunits that are mutated in epilepsy
复制标题
DOI：
10.1073/pnas.090092797
复制
发表时间：
2000-04-25
影响因子：
11.1
通讯作者：
Jan, LY
中科院分区：
文献类型：
--
作者：
Cooper, EC;Aldape, KD;Jan, LY
乙酰胆碱通过抑制 M 通道来兴奋许多中枢和自主神经元。缓慢激活、非失活的电压门控钾通道。我们在这里提供有关人脑 KCNQ2 和 KCNQ3 的体内分布和生化特征的信息，这两个通道亚基在体外表达时形成 M 通道，并且在突变时引起显性遗传性癫痫综合征，即良性新生儿家族性惊厥。 KCNQ2 和 KCNQ3 蛋白以体细胞树突模式共定位于人类皮质和海马的锥体和多态神经元上。 KCNQ2（而非 KCNQ3）的免疫反应性在一些末端区域也很突出，表明 M 通道的独特亚组在调节动作电位传播和神经递质释放中发挥突触前作用。 KCNQ2 和 KCNQ3 可以从脑裂解物中进行免疫共沉淀。此外，KCNQ2 和 KCNQ3 与 Triton X-100 不溶性蛋白复合物中的微管蛋白和蛋白激酶 A 共同关联。该复合物与低密度膜筏或 N-甲基-D-天冬氨酸受体、PSD-95 支架蛋白或其他测试的钾通道无关。因此，我们的研究提供了一种信号复合物的观点，该信号复合物可能对认知功能和癫痫很重要。对该复合物的分析可能揭示将毒蕈碱乙酰胆碱受体激活与 M 通道抑制联系起来的未知转导途径。
Acetylcholine excites many central and autonomic neurons through inhibition of M-channels. slowly activating, noninactivating voltage-gated potassium channels. We here provide information regarding the in vivo distribution and biochemical characteristics of human brain KCNQ2 and KCNQ3, two channel subunits that form M-channels when expressed in vitro, and, when mutated, cause the dominantly inherited epileptic syndrome, benign neonatal familial convulsions. KCNQ2 and KCNQ3 proteins are colocalized in a somatodendritic pattern on pyramidal and polymorphic neurons in the human cortex and hippocampus. Immunoreactivity for KCNQ2, but not KCNQ3, is also prominent in some terminal fields, suggesting a presynaptic role for a distinct subgroup of M-channels in the regulation of action potential propagation and neurotransmitter release. KCNQ2 and KCNQ3 can be coimmunoprecipitated from brain lysates. Further, KCNQ2 and KCNQ3 are coassociated with tubulin and protein kinase A within a Triton X-100-insoluble protein complex. This complex is not associated with low-density membrane rafts or with N-methyl-D-aspartate receptors, PSD-95 scaffolding proteins, or other potassium channels tested. Our studies thus provide a view of a signaling complex that may be important for cognitive function as well as epilepsy. Analysis of this complex may shed light on the unknown transduction pathway linking muscarinic acetylcholine receptor activation to M-channel inhibition.