Université Côte d'Azur, INRAE, CNRS, ISA , France.
Virulence. 2020 Dec;11(1):1512-1521. doi: 10.1080/21505594.2020.1838116.
Venosomes are extracellular vesicles found in the venom of endoparasitoids wasps, which transport and target virulence factors to impair the parasitoid egg encapsulation by the lamellocytes of their host larva. Using the co-immunolocalization of fluorescent venosomes and one of the putative-transported virulence factors, LbGAP, with known markers of cellular endocytosis, we show that venosomes endocytosis by lamellocytes is not a process dependent on clathrin or macropinocytosis and internalization seems to bypass the early endosomal compartment Rab5. After internalization, LbGAP colocalizes strongly with flotillin-1 and the GPI-anchored protein Atilla/L1 (a lamellocyte surface marker) suggesting that entry occurs a flotillin/lipid raft-dependent pathway. Once internalized, venosomes reach all intracellular compartments, including late and recycling endosomes, lysosomes, and the endoplasmic reticulum network. Venosomes therefore enter their target cells by a specific mechanism and the virulence factors are widely distributed in the lamellocytes' compartments to impair their functions.
在寄生蜂的毒液中发现了一种称为囊泡的细胞外囊泡，它能够运输和靶向毒力因子，从而破坏宿主幼虫的 lamellocytes 对寄生蜂卵的包被。通过荧光囊泡和一种假定的运输毒力因子 LbGAP 与已知的细胞内吞作用标记物的共免疫定位，我们表明 lamellocytes 通过内吞作用摄取囊泡不是一个依赖于网格蛋白或巨胞饮作用的过程，并且内化似乎绕过了早期内体 Rab5 区室。内吞作用后，LbGAP 与 flotillin-1 和 GPI 锚定蛋白 Atilla/L1（lamellocyte 表面标记物）强烈共定位，表明进入是通过 flotillin/脂筏依赖性途径发生的。一旦被内化，囊泡到达所有细胞内区室，包括晚期和再循环内体、溶酶体和内质网网络。因此，囊泡通过特定的机制进入靶细胞，毒力因子在 lamellocytes 的区室中广泛分布，从而破坏它们的功能。
