ADAM22, A Kv1 Channel-Interacting Protein, Recruits Membrane-Associated Guanylate Kinases to Juxtaparanodes of Myelinated Axons
ADAM22, A Kv1 Channel-Interacting Protein, Recruits Membrane-Associated Guanylate Kinases to Juxtaparanodes of Myelinated Axons
复制标题
DOI：
10.1523/jneurosci.4661-09.2010
复制
发表时间：
2010-01-20
影响因子：
5.3
通讯作者：
Rasband, Matthew N.
中科院分区：
文献类型：
--
作者：
Ogawa, Yasuhiro;Oses-Prieto, Juan;Rasband, Matthew N.
群集性KV1K+通道调节有髓轴突、轴突起始段和小脑篮细胞终末(BCT)旁的神经元兴奋性。这些通道是包括细胞黏附分子和支架蛋白在内的更大蛋白质复合体的一部分。为了确定调节轴突KV1通道蛋白复合体的组装、聚集和/或维持的蛋白质，我们用免疫沉淀Kv1.2α亚基，然后用质谱仪鉴定相互作用的蛋白质。我们发现去整合素和金属蛋白酶22(ADAM22)是KV1通道复合体的一个组成部分，ADAM22免疫共沉淀Kv1.2和膜相关鸟苷酸晚期蛋白(MAGUKs)PSD-93和PSD-95。当在异种细胞中与MAGUKs共表达时，ADAM22和KV1通道被募集到膜表面簇中。然而，Kv1.2与ADAM22和MAGUK的共表达不会改变通道属性。在所有已知的KV1通道相互作用蛋白中，只有ADAM22存在于KV1通道聚集的每个位置。对CASPR缺失小鼠的分析表明，与其他先前描述的旁结节蛋白一样，旁结节连接的中断导致ADAM22重新分布到结旁区域。对Caspr2、PSD-93、PSD-95和双PSD-93/PSD-95缺失小鼠的分析表明，ADAM22在BCT上聚集需要PSD-95，但ADAM22在邻近肝阳极聚集不需要PSD-93或PSD-95。与此形成直接对比的是，对ADAM22缺失小鼠的分析表明，PSD-93和PSD-95的并列结节聚集需要ADAM22，而Kv1.2和Caspr2聚集在ADAM22缺失小鼠中是正常的。因此，ADAM22是KV1 K+通道复合体的轴突成分，它将MAGUK招募到肝旁。
Clustered Kv1 K+ channels regulate neuronal excitability at juxtaparanodes of myelinated axons, axon initial segments, and cerebellar basket cell terminals (BCTs). These channels are part of a larger protein complex that includes cell adhesion molecules and scaffolding proteins. To identify proteins that regulate assembly, clustering, and/or maintenance of axonal Kv1 channel protein complexes, we immunoprecipitated Kv1.2 alpha subunits, and then used mass spectrometry to identify interacting proteins. We found that a disintegrin and metalloproteinase 22 (ADAM22) is a component of the Kv1 channel complex and that ADAM22 coimmunoprecipitates Kv1.2 and the membrane-associated guanylate kinases (MAGUKs) PSD-93 and PSD-95. When coexpressed with MAGUKs in heterologous cells, ADAM22 and Kv1 channels are recruited into membrane surface clusters. However, coexpression of Kv1.2 with ADAM22 and MAGUKs does not alter channel properties. Among all the known Kv1 channel-interacting proteins, only ADAM22 is found at every site where Kv1 channels are clustered. Analysis of Caspr-null mice showed that, like other previously described juxtaparanodal proteins, disruption of the paranodal junction resulted in redistribution of ADAM22 into paranodal zones. Analysis of Caspr2-, PSD-93-, PSD-95-, and double PSD-93/PSD-95-null mice showed ADAM22 clustering at BCTs requires PSD- 95, but ADAM22 clustering at juxtaparanodes requires neither PSD-93 nor PSD-95. In direct contrast, analysis of ADAM22-null mice demonstrated juxtaparanodal clustering of PSD-93 and PSD-95 requires ADAM22, whereas Kv1.2 and Caspr2 clustering is normal inADAM22-null mice. Thus, ADAM22 is an axonal component of the Kv1 K+ channel complex that recruits MAGUKs to juxtaparanodes.