Structural determinants of interaction, trafficking and function in the ClC-2/MLC1 subunit GlialCAM involved in leukodystrophy
Structural determinants of interaction, trafficking and function in the ClC-2/MLC1 subunit GlialCAM involved in leukodystrophy
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DOI：
10.1113/jp270467
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发表时间：
2015-09-15
影响因子：
5.5
通讯作者：
Estevez, Raul
中科院分区：
文献类型：
--
作者：
Capdevila-Nortes, Xavier;Jeworutzki, Elena;Estevez, Raul
编码星形胶质细胞蛋白MLC1、细胞粘附分子GlialCAM或Cl-通道ClC-2的基因突变是人类脑白质营养不良的基础。GlialCAM与自身、MLC1和ClC-2结合，并将这些蛋白质引导至细胞-细胞接触。此外，GlialCAM显著激活ClC-2介导的电流。在本研究中，我们使用诱变研究结合功能和生化分析，以确定GlialCAM的哪些部分需要执行这些细胞功能。我们发现GlialCAM的胞外结构域对于细胞连接靶向和介导与自身或与MLC1和ClC-2的相互作用是必需的。C-末端对于适当靶向细胞-细胞连接也是必需的，但对于生物化学相互作用不是必需的。最后，我们鉴定了GlialCAM跨膜段的前三个氨基酸对于ClC-2电流的激活是必需的，但对于靶向或生化相互作用不是必需的。我们的研究结果提供了新的机制的见解有关的GlialCAM的细胞生物学和MLC1和ClC-2的功能的调节。
Mutations in the genes encoding the astrocytic protein MLC1, the cell adhesion molecule GlialCAM or the Cl- channel ClC-2 underlie human leukodystrophies. GlialCAM binds to itself, to MLC1 and to ClC-2, and directs these proteins to cell-cell contacts. In addition, GlialCAM dramatically activates ClC-2 mediated currents. In the present study, we used mutagenesis studies combined with functional and biochemical analyses to determine which parts of GlialCAM are required to perform these cellular functions. We found that the extracellular domain of GlialCAM is necessary for cell junction targeting and for mediating interactions with itself or with MLC1 and ClC-2. The C-terminus is also necessary for proper targeting to cell-cell junctions but is not required for the biochemical interaction. Finally, we identified the first three amino acids of the transmembrane segment of GlialCAM as being essential for the activation of ClC-2 currents but not for targeting or biochemical interaction. Our results provide new mechanistic insights concerning the regulation of the cell biology and function of MLC1 and ClC-2 by GlialCAM.