Plasma membrane localization of MLC1 regulates cellular morphology and motility
Plasma membrane localization of MLC1 regulates cellular morphology and motility
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DOI：
10.1186/s13041-019-0540-6
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发表时间：
2019-12-30
期刊：
影响因子：
3.6
通讯作者：
Lim, Hyun-Ho
中科院分区：
文献类型：
--
作者：
Hwang, Junmo;Vu, Hung M.;Lim, Hyun-Ho
背景：伴有皮质下囊肿（MLC）的巨脑性白质脑病是一种罕见的婴儿发病的脑白质营养不良。该疾病主要由 MLC1 突变引起，导致一系列表型结果，包括髓磷脂和星形胶质细胞空泡化、皮质下囊肿、脑水肿和巨头畸形。最近的研究表明，MLC1、GlialCAM 和 ClC-2 通道之间的功能相互作用在神经元、神经胶质和血管稳态的调节中发挥着关键作用。然而，MLC1 在细胞稳态通讯中的生理作用仍然知之甚少。在本研究中，我们研究了MLC1的细胞功能及其对细胞-细胞相互作用的影响。方法：利用共聚焦和活细胞成像技术分析MLC1依赖的细胞形态和运动。采用免疫印迹、免疫共沉淀和表面生物素化等生化方法来支持数据。结果：我们发现 MLC1 表达和定位的改变通过肌动蛋白重塑导致细胞形态和运动性的巨大改变。 MLC1 过度表达诱导丝状伪足形成并抑制运动。而且，患者来源的 MLC1 突变体中表达的 MLC1 蛋白导致了 ER 的捕获，尽管没有观察到形态或运动性的变化。有趣的是，Mlc1 的敲低诱导了 Arp3-Cortactin 相互作用、板状伪足的形成，并增加了星形胶质细胞的膜皱褶。这些数据表明，表达的 MLC1 在质膜上的亚细胞定位对于通过 ARP2/3 复合物改变肌动蛋白动力学至关重要。因此，我们的结果表明，致病性突变体 MLC1 的错误分配可能会扰乱 MLC 患者的稳定细胞间通讯和星形胶质细胞的稳态调节。
Background: Megalencephalic leukoencephalopathy with subcortical cysts (MLC) is a rare form of infantile-onset leukodystrophy. The disorder is caused primarily by mutations of MLC1 that leads to a series of phenotypic outcomes including vacuolation of myelin and astrocytes, subcortical cysts, brain edema, and macrocephaly. Recent studies have indicated that functional interactions among MLC1, GlialCAM, and ClC-2 channels play key roles in the regulation of neuronal, glial and vascular homeostasis. However, the physiological role of MLC1 in cellular homeostatic communication remains poorly understood. In the present study, we investigated the cellular function of MLC1 and its effects on cell-cell interactions.Methods: MLC1-dependent cellular morphology and motility were analyzed by using confocal and live cell imaging technique. Biochemical approaches such as immunoblotting, co-immunoprecipitation, and surface biotinylation were conducted to support data.Results: We found that the altered MLC1 expression and localization led to a great alteration in cellular morphology and motility through actin remodeling. MLC1 overexpression induced filopodia formation and suppressed motility. And, MLC1 proteins expressed in patient-derived MLC1 mutants resulted in trapping in the ER although no changes in morphology or motility were observed. Interestingly knockdown of Mlc1 induced Arp3-Cortactin interaction, lamellipodia formation, and increased the membrane ruffling of the astrocytes. These data indicate that subcellular localization of expressed MLC1 at the plasma membrane is critical for changes in actin dynamics through ARP2/3 complex. Thus, our results suggest that misallocation of pathogenic mutant MLC1 may disturbs the stable cell-cell communication and the homeostatic regulation of astrocytes in patients with MLC.