Motor Protein Myo1c Is a Podocyte Protein That Facilitates the Transport of Slit Diaphragm Protein Neph1 to the Podocyte Membrane
Motor Protein Myo1c Is a Podocyte Protein That Facilitates the Transport of Slit Diaphragm Protein Neph1 to the Podocyte Membrane
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DOI：
10.1128/mcb.05051-11
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发表时间：
2011-05-01
影响因子：
5.3
通讯作者：
Nihalani, D.
中科院分区：
文献类型：
--
作者：
Arif, E.;Wagner, M. C.;Nihalani, D.
足细胞蛋白Neph1和nephrin在足细胞膜上组织信号复合物，形成功能性肾小球滤过屏障的结构框架。调节这些蛋白质进出膜的运动的机制目前尚不清楚。这项研究确定了一种新的相互作用之间的Neph1和马达蛋白Myo1c，其中Myo1c在靶向Neph1的足细胞膜发挥积极的作用。使用在体内和体外实验中，我们提供的数据支持Neph1和Myo1c之间的直接相互作用，这是动态和肌动蛋白依赖。与野生型Myo1c不同，在表达显性阴性Myo1c的足细胞中，Neph1的膜定位显著减少。此外，Neph1未能定位在足细胞的细胞膜和Myo1c耗尽足细胞的细胞连接。我们进一步证明，类似于Neph1，Myo1c也结合nephrin，并减少其在足细胞膜上的定位。Myo1c敲低细胞的功能分析显示细胞迁移的缺陷，如通过伤口测定所确定的。此外，通过跨上皮电阻（TER）和牛血清白蛋白（BSA）渗透性测定，在Myo1c敲低细胞中形成紧密连接的能力受损。这些结果确定了一种新的Myo1c依赖的分子机制，介导的动态组织的Neph1和nephrin在狭缝隔膜，是足细胞功能的关键。
The podocyte proteins Neph1 and nephrin organize a signaling complex at the podocyte cell membrane that forms the structural framework for a functional glomerular filtration barrier. Mechanisms regulating the movement of these proteins to and from the membrane are currently unknown. This study identifies a novel interaction between Neph1 and the motor protein Myo1c, where Myo1c plays an active role in targeting Neph1 to the podocyte cell membrane. Using in vivo and in vitro experiments, we provide data supporting a direct interaction between Neph1 and Myo1c which is dynamic and actin dependent. Unlike wild-type Myo1c, the membrane localization of Neph1 was significantly reduced in podocytes expressing dominant negative Myo1c. In addition, Neph1 failed to localize at the podocyte cell membrane and cell junctions in Myo1c-depleted podocytes. We further demonstrate that similarly to Neph1, Myo1c also binds nephrin and reduces its localization at the podocyte cell membrane. A functional analysis of Myo1c knockdown cells showed defects in cell migration, as determined by a wound assay. In addition, the ability to form tight junctions was impaired in Myo1c knockdown cells, as determined by transepithelial electric resistance (TER) and bovine serum albumin (BSA) permeability assays. These results identify a novel Myo1c-dependent molecular mechanism that mediates the dynamic organization of Neph1 and nephrin at the slit diaphragm and is critical for podocyte function.