School of Life Sciences, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Korea.
Center for Cell Mechanobiology, GIST, Gwangju 61005, Korea.
Mol Cells. 2021 Apr 30;44(4):214-222. doi: 10.14348/molcells.2021.2217.
Phosphatidylserine (PS), a negatively charged phospholipid exclusively located in the inner leaflet of the plasma membrane, is involved in various cellular processes such as blood coagulation, myoblast fusion, mammalian fertilization, and clearance of apoptotic cells. Proteins that specifically interact with PS must be identified to comprehensively understand the cellular processes involving PS. However, only a limited number of proteins are known to associate with PS. To identify PS-associating proteins, we performed a pulldown assay using streptavidin-coated magnetic beads on which biotin-linked PS was immobilized. Using this approach, we identified Hsd17b4, a peroxisomal protein, as a PS-associating protein. Hsd17b4 strongly associated with PS, but not with phosphatidylcholine or sphingomyelin, and the Scp-2-like domain of Hsd17b4 was responsible for this association. The association was disrupted by PS in liposomes, but not by free PS or the components of PS. In addition, translocation of PS to the outer leaflet of the plasma membrane enriched Hsd17b4 in peroxisomes. Collectively, this study suggests an unexpected role of PS as a regulator of the subcellular localization of Hsd17b4.
磷脂酰丝氨酸（PS）是一种带负电荷的磷脂，只位于质膜的内小叶，参与多种细胞过程，如血液凝固、成肌细胞融合、哺乳动物受精和凋亡细胞的清除。必须鉴定与 PS 特异性相互作用的蛋白质，才能全面了解涉及 PS 的细胞过程。然而，已知与 PS 相关的蛋白质数量有限。为了鉴定 PS 结合蛋白，我们使用链霉亲和素包被的磁珠进行了下拉实验，该磁珠上固定了生物素化的 PS。通过这种方法，我们鉴定了过氧化物酶体蛋白 Hsd17b4 是 PS 结合蛋白。Hsd17b4 与 PS 强烈结合，但与磷脂酰胆碱或鞘磷脂不结合，Hsd17b4 的 Scp-2 样结构域负责这种结合。这种结合被脂质体中的 PS 破坏，但不是游离 PS 或 PS 的成分。此外，PS 向质膜外小叶的易位使 Hsd17b4 在过氧化物酶体中富集。总的来说，这项研究表明 PS 作为 Hsd17b4 亚细胞定位调节剂的作用是出乎意料的。
