Yu W, Xu J, Li M
Department of Physiology, School of Medicine, Johns Hopkins University Baltimore, Maryland 21205, USA.
Neuron. 1996 Feb;16(2):441-53. doi: 10.1016/s0896-6273(00)80062-8.
There are at least five subfamilies of Shaker-like K+ channels. The diverse function of K+ channels are thought to be further modulated by hydrophilic beta subunits. Here we report that Kv beta 1 inactivates RCK4 and Shaker B K+ channels of the Kv1 subfamily, but not Shal2 of the Kv4 subfamily. This correlates the subfamily-specific bindings of Kv beta 1 to the cytoplasmic N-terminal domains of Kv1 alpha subunits. We map the Kv beta 1-binding site to a region overlapping NABKv1, a domain that specifies different Kv1 alpha subunits to form heterotetramers. Using chimeric alpha subunits, we demonstrate that NABKv1 is essential for the Kv beta 1-mediated inactivation. These results suggest that Kv beta 1 modulates a subset of K+ channels through the specific assembly of alpha-beta complexes and reveal the dual function of the NAB domain in mediating the assembly of both alpha-alpha and alpha-beta complexes.
至少有五个亚家族的类Shaker钾离子通道。钾离子通道的多种功能被认为会进一步受到亲水性β亚基的调节。在此我们报告，Kvβ1可使Kv1亚家族的RCK4和Shaker B钾离子通道失活，但不会使Kv4亚家族的Shal2失活。这与Kvβ1与Kv1α亚基胞质N端结构域的亚家族特异性结合相关。我们将Kvβ1结合位点定位到与NABKv1重叠的区域，NABKv1是一个指定不同Kv1α亚基形成异源四聚体的结构域。使用嵌合α亚基，我们证明NABKv1对于Kvβ1介导的失活至关重要。这些结果表明，Kvβ1通过α-β复合物的特异性组装来调节一部分钾离子通道，并揭示了NAB结构域在介导α-α和α-β复合物组装中的双重功能。
