The potassium channel auxiliary subunit Kvβ2 (Kcnab2) regulates Kv1 channels and dopamine neuron firing.
The potassium channel auxiliary subunit Kvβ2 (Kcnab2) regulates Kv1 channels and dopamine neuron firing.
复制标题
钾通道辅助亚基 Kvβ2 (Kcnab2) 调节 Kv1 通道和多巴胺神经元放电。
DOI：
10.1152/jn.00194.2022
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发表时间：
2022
影响因子：
2.5
通讯作者：
Soden,MartaE
中科院分区：
文献类型：
--
作者：
Yee,JoshuaX;Rastani,Ariana;Soden,MartaE
离子通道复合物通常由孔形成亚基和辅助亚基组成，辅助亚基不直接传导电流，但可以调节运输或改变通道特性。由于缺乏特定的药理学试剂和组成性敲除模型中发育补偿的潜力，分离这些辅助亚基在神经元中的作用已被证明是困难的。在这里，我们使用细胞类型特异性病毒介导的CRISPR/Cas9诱变来靶向成年小鼠大脑多巴胺神经元中的钾通道辅助亚基Kvβ2（Kcnab 2）。我们发现，突变ofKcnab 2减少表面表达的Kv1.2，主要的Kv 1孔形成亚基表达在多巴胺神经元，并转移电压依赖性失活的钾通道电流向更超极化的电位。Kcnab 2的缺失使切片中记录的自发放电多巴胺神经元的动作电位波形变宽，后超极化幅度降低，尖峰时间不规则性和兴奋性增加，所有这些都与钾通道电流的减少一致。孔形成亚基Kv1.2（Kcna 2）的诱变也观察到类似的效果。这些结果确定Kv 1电流是多巴胺神经元放电的重要贡献者，并证明了Kvβ2亚基在调节这些离子通道的运输和门控特性中的作用。此外，他们证明了CRISPR介导的诱变在研究以前难以分离的离子通道亚基中的实用性。新&值得注意的是，我们在小鼠多巴胺神经元中利用CRISPR/Cas9介导的诱变来靶向编码Kvβ2的基因，Kvβ2是一种辅助亚基，形成Kv 1通道复合物的一部分。我们发现，Kvβ2的缺失通过减少成孔亚基的表面表达和改变通道失活的电压依赖性来改变动作电位特性。这项工作建立了Kvβ2亚基和Kv 1复合物在调节多巴胺神经元活性中的新功能。
Ion channel complexes typically consist of both pore-forming subunits and auxiliary subunits that do not directly conduct current but can regulate trafficking or alter channel properties. Isolating the role of these auxiliary subunits in neurons has proved difficult due to a lack of specific pharmacological agents and the potential for developmental compensation in constitutive knockout models. Here, we use cell-type-specific viral-mediated CRISPR/Cas9 mutagenesis to target the potassium channel auxiliary subunit Kvβ2 (Kcnab2) in dopamine neurons in the adult mouse brain. We find that mutagenesis ofKcnab2reduces surface expression of Kv1.2, the primary Kv1 pore-forming subunit expressed in dopamine neurons, and shifts the voltage dependence of inactivation of potassium channel currents toward more hyperpolarized potentials. Loss ofKcnab2broadens the action potential waveform in spontaneously firing dopamine neurons recorded in slice, reduces the afterhyperpolarization amplitude, and increases spike timing irregularity and excitability, all of which is consistent with a reduction in potassium channel current. Similar effects were observed with mutagenesis of the pore-forming subunit Kv1.2 (Kcna2). These results identify Kv1 currents as important contributors to dopamine neuron firing and demonstrate a role for Kvβ2 subunits in regulating the trafficking and gating properties of these ion channels. Furthermore, they demonstrate the utility of CRISPR-mediated mutagenesis in the study of previously difficult to isolate ion channel subunits.NEW & NOTEWORTHYHere, we utilize CRISPR/Cas9-mediated mutagenesis in dopamine neurons in mice to target the gene encoding Kvβ2, an auxiliary subunit that forms a part of Kv1 channel complexes. We find that the absence of Kvβ2 alters action potential properties by reducing surface expression of pore-forming subunits and shifting the voltage dependence of channel inactivation. This work establishes a new function for Kvβ2 subunits and Kv1 complexes in regulating dopamine neuron activity.