Arnold D B, Clapham D E
Howard Hughes Medical Institute and Children's Hospital, Boston, Massachusetts 02115, USA.
Neuron. 1999 May;23(1):149-57. doi: 10.1016/s0896-6273(00)80761-8.
Ion channels and PSD-95 are colocalized in specific neuronal subcellular locations by an unknown mechanism. To investigate mechanisms of localization, we used biolistic techniques to express GFP-tagged PSD-95 (PSD-95:GFP) and the K(+)-selective channel Kv1.4 in slices of rat cortex. In pyramidal cells, PSD-95:GFP required a single PDZ domain and a region including the SH3 domain for localization to postsynaptic sites. When transfected alone, PSD-95:GFP was present in dendrites but absent from axons. When cotransfected with Kv1.4, PSD-95:GFP appeared in both axons and dendrites, while Kv1.4 was restricted to axons. When domains that mediate the interaction of Kv1.4 and PSD-95 were disrupted, Kv1.4 localized nonspecifically. Our results provide evidence that Kv1.4 itself may determine its subcellular location, while an associated MAGUK protein is a necessary but not sufficient cofactor.
离子通道和PSD - 95通过未知机制共定位于特定的神经元亚细胞位置。为了研究定位机制，我们使用生物弹道技术在大鼠皮质切片中表达绿色荧光蛋白标记的PSD - 95（PSD - 95:GFP）和钾离子选择性通道Kv1.4。在锥体细胞中，PSD - 95:GFP需要一个单一的PDZ结构域和一个包括SH3结构域的区域才能定位于突触后位点。单独转染时，PSD - 95:GFP存在于树突中，但轴突中不存在。与Kv1.4共转染时，PSD - 95:GFP出现在轴突和树突中，而Kv1.4仅限于轴突。当介导Kv1.4与PSD - 95相互作用的结构域被破坏时，Kv1.4会非特异性定位。我们的结果提供了证据，表明Kv1.4本身可能决定其亚细胞位置，而相关的膜相关鸟苷酸激酶（MAGUK）蛋白是一个必要但不充分的辅助因子。
