Rhodes K J, Strassle B W, Monaghan M M, Bekele-Arcuri Z, Matos M F, Trimmer J S
Central Nervous System Disorders, Wyeth-Ayerst Research, Princeton, New Jersey 08543, USA.
J Neurosci. 1997 Nov 1;17(21):8246-58. doi: 10.1523/JNEUROSCI.17-21-08246.1997.
The differential expression and association of cytoplasmic beta-subunits with pore-forming alpha-subunits may contribute significantly to the complexity and heterogeneity of voltage-gated K+ channels in excitable cells. Here we examined the association and colocalization of two mammalian beta-subunits, Kvbeta1 and Kvbeta2, with the K+ channel alpha-subunits Kv1.1, Kv1.2, Kv1.4, Kv1.6, and Kv2.1 in adult rat brain. Reciprocal coimmunoprecipitation experiments using subunit-specific antibodies indicated that Kvbeta1 and Kvbeta2 associate with all the Kv1 alpha-subunits examined, and with each other, but not with Kv2.1. A much larger portion of the total brain pool of Kv1-containing channel complexes was found associated with Kvbeta2 than with Kvbeta1. Single- and multiple-label immunohistochemical staining indicated that Kvbeta1 codistributes extensively with Kv1.1 and Kv1.4 in cortical interneurons, in the hippocampal perforant path and mossy fiber pathways, and in the globus pallidus and substantia nigra. Kvbeta2 codistributes extensively with Kv1.1 and Kv1.2 in all brain regions examined and was strikingly colocalized with these alpha-subunits in the juxtaparanodal region of nodes of Ranvier as well as in the axons and terminals of cerebellar basket cells. Taken together, these data provide a direct demonstration that Kvbeta1 and Kvbeta2 associate and colocalize with Kv1 alpha-subunits in native tissues and provide a biochemical and neuroanatomical basis for the differential contribution of Kv1 alpha- and beta-subunits to electrophysiologically diverse neuronal K+ currents.
细胞质β亚基与形成孔道的α亚基之间的差异表达及关联，可能对可兴奋细胞中电压门控钾通道的复杂性和异质性有显著贡献。在此，我们研究了成年大鼠脑中两种哺乳动物β亚基Kvβ1和Kvβ2与钾通道α亚基Kv1.1、Kv1.2、Kv1.4、Kv1.6和Kv2.1的关联及共定位情况。使用亚基特异性抗体进行的相互免疫共沉淀实验表明，Kvβ1和Kvβ2与所有检测的Kv1α亚基相互关联，且它们彼此之间也相互关联，但不与Kv2.1关联。结果发现，含Kv1的通道复合物在全脑库中的很大一部分与Kvβ2相关联，而非Kvβ1。单标记和多标记免疫组织化学染色表明，Kvβ1在皮质中间神经元、海马穿通通路和苔藓纤维通路以及苍白球和黑质中与Kv1.1和Kv1.4广泛共分布。Kvβ2在所有检测的脑区中与Kv1.1和Kv1.2广泛共分布，并且在郎飞结的旁结区以及小脑篮状细胞的轴突和终末中与这些α亚基显著共定位。综上所述，这些数据直接证明了Kvβ1和Kvβ2在天然组织中与Kv1α亚基相互关联并共定位，为Kv1α亚基和β亚基对电生理上不同的神经元钾电流的差异贡献提供了生化和神经解剖学基础。
