Knisely Jane M, Lee Jiyeon, Bu Guojun
Department of Pediatrics, Washington University School of Medicine, St.Louis, MO, USA.
Methods Mol Biol. 2008;457:319-32. doi: 10.1007/978-1-59745-261-8_24.
Receptor trafficking is essential to the delivery of nutrients and to the proper regulation of signaling pathways in mammalian cells. Numerous transmembrane receptors undergo clathrin-mediated endocytosis, followed by sorting in the early endosome. The low-density lipoprotein (LDL) receptor-related protein (LRP) is a multiligand endocytic receptor and a member of the LDL receptor family. At the cell surface, it binds to and continuously internalizes numerous ligands including lipoproteins, proteases, protease inhibitors, growth factors, and beta-amyloid precursor protein via clathrin-mediated endocytosis. Its rapid endocytosis rate allows efficient clearance of extracellular and transmembrane ligands. Once internalized into the early or sorting endosome, LRP ligands are delivered to lysosomes to be degraded, whereas LRP is efficiently recycled to the plasma membrane. Herein, the authors describe quantitative methods to measure the endocytosis and recycling capacity of receptors, using LRP as a model receptor.
受体转运对于哺乳动物细胞中营养物质的传递以及信号通路的正常调节至关重要。许多跨膜受体通过网格蛋白介导的内吞作用进入细胞，随后在内体中进行分选。低密度脂蛋白（LDL）受体相关蛋白（LRP）是一种多配体胞吞受体，属于LDL受体家族成员。在细胞表面，它通过网格蛋白介导的内吞作用与多种配体结合并持续内化，这些配体包括脂蛋白、蛋白酶、蛋白酶抑制剂、生长因子和β-淀粉样前体蛋白。其快速的内吞速率使得细胞外和跨膜配体能够被有效清除。一旦内化进入早期或分选内体，LRP配体就会被转运至溶酶体进行降解，而LRP则被高效循环至质膜。在此，作者描述了以LRP作为模型受体来测量受体胞吞作用和循环能力的定量方法。
