Neurovascular Unit Research Group, Korea Brain Research Institute (KBRI), 61 Cheomdan-ro, Dong-gu, Daegu 41068, Republic of Korea.
Brain Research Core Facility, Korea Brain Research Institute (KBRI), Daegu, Republic of Korea.
Open Biol. 2021 Dec;11(12):210103. doi: 10.1098/rsob.210103. Epub 2021 Dec 1.
MLC1 is a membrane protein mainly expressed in astrocytes, and genetic mutations lead to the development of a leukodystrophy, megalencephalic leukoencephalopathy with subcortical cysts disease. Currently, the biochemical properties of the MLC1 protein are largely unknown. In this study, we aimed to characterize the transmembrane (TM) topology and oligomeric nature of the MLC1 protein. Systematic immunofluorescence staining data revealed that the MLC1 protein has eight TM domains and that both the N- and C-terminus face the cytoplasm. We found that MLC1 can be purified as an oligomer and could form a trimeric complex in both detergent micelles and reconstituted proteoliposomes. Additionally, a single-molecule photobleaching experiment showed that MLC1 protein complexes could consist of three MLC1 monomers in the reconstituted proteoliposomes. These results can provide a basis for both the high-resolution structural determination and functional characterization of the MLC1 protein.
MLC1 是一种主要在星形胶质细胞中表达的膜蛋白，遗传突变会导致脑白质营养不良、巨脑性脑白质病伴皮质下囊肿病的发生。目前，MLC1 蛋白的生化特性在很大程度上尚不清楚。在这项研究中，我们旨在表征 MLC1 蛋白的跨膜（TM）拓扑结构和寡聚性质。系统免疫荧光染色数据显示，MLC1 蛋白具有八个 TM 结构域，并且 N-和 C-末端均朝向细胞质。我们发现 MLC1 可以作为寡聚体被纯化，并可以在去污剂胶束和重建的质体中形成三聚体复合物。此外，单分子荧光漂白实验表明，MLC1 蛋白复合物可以由重建质体中的三个 MLC1 单体组成。这些结果可为 MLC1 蛋白的高分辨率结构测定和功能表征提供基础。
