Proteostasis and Proteolytic Signalling Lab, Chronic Diseases Research Centre (CEDOC), NOVA Medical School, Faculdade de Ciencias Medicas, Universidade NOVA de Lisboa, Lisbon, Portugal.
Fish Facility, CEDOC, NOVA Medical School, Faculdade de Ciencias Medicas, Universidade NOVA de Lisboa, Lisbon, Portugal.
Sci Adv. 2022 Mar 25;8(12):eabm1140. doi: 10.1126/sciadv.abm1140.
Exosomes are extracellular vesicles of endosomal origin that are released by practically all cell types across metazoans. Exosomes are active vehicles of intercellular communication and can transfer lipids, RNAs, and proteins between different cells, tissues, or organs. Here, we describe a mechanism whereby proteins containing a KFERQ motif pentapeptide are loaded into a subpopulation of exosomes in a process that is dependent on the membrane protein LAMP2A. Moreover, we demonstrate that this mechanism is independent of the ESCRT machinery but dependent on HSC70, CD63, Alix, Syntenin-1, Rab31, and ceramides. We show that the master regulator of hypoxia HIF1A is loaded into exosomes by this mechanism to transport hypoxia signaling to normoxic cells. In addition, by tagging fluorescent proteins with KFERQ-like sequences, we were able to follow the interorgan transfer of exosomes. Our findings open new avenues for exosome engineering by allowing the loading of bioactive proteins by tagging them with KFERQ-like motifs.
外泌体是起源于内体的细胞外囊泡，几乎所有后生动物的所有细胞类型都会释放外泌体。外泌体是细胞间通讯的活性载体，可在不同细胞、组织或器官之间转移脂质、RNA 和蛋白质。在这里，我们描述了一种机制，其中含有 KFERQ 基序五肽的蛋白质被加载到外泌体的亚群中，该过程依赖于膜蛋白 LAMP2A。此外，我们证明该机制不依赖于 ESCRT 机制，但依赖于 HSC70、CD63、Alix、Syntenin-1、Rab31 和神经酰胺。我们表明，缺氧的主调控因子 HIF1A 通过这种机制被加载到外泌体中，以将缺氧信号转导到正常氧细胞。此外，通过用 KFERQ 样序列标记荧光蛋白，我们能够追踪外泌体的器官间转移。我们的发现为外泌体工程开辟了新途径，允许通过用 KFERQ 样基序标记它们来加载生物活性蛋白。
