INSERM Avenir team Trafic intracellulaire et polarité chez C. elegans, Rennes, France.
J Thromb Haemost. 2011 Feb;9(2):392-401. doi: 10.1111/j.1538-7836.2010.04138.x.
Endothelial von Willebrand factor (VWF) mediates platelet adhesion and acts as a protective chaperone to clotting factor VIII. Rapid release of highly multimerized VWF is particularly effective in promoting hemostasis. To produce this protein, an elaborate biogenesis is required, culminating at the trans-Golgi network (TGN) in storage within secretory granules called Weibel-Palade bodies (WPB). Failure to correctly form these organelles can lead to uncontrolled secretion of low-molecular-weight multimers of VWF. The TGN-associated adaptor AP-1 and its interactors clathrin, aftiphilin and γ-synergin are essential to initial WPB formation at the Golgi apparatus, and thus to VWF storage and secretion.
To identify new proteins implicated in VWF storage and/or secretion.
A genomewide RNA interference (RNAi) screen was performed in the Nematode C. elegans to identify new AP-1 genetic interactors.
The small GTPase Rab10 was found to genetically interact with a partial loss of function of AP-1 in C. elegans. We investigated Rab10 in human primary umbilical vein endothelial cells (HUVECs). We report that Rab10 is enriched at the Golgi apparatus, where WPB are formed, and that in cells where Rab10 expression has been suppressed by siRNA, VWF secretion is altered: the amount of rapidly released VWF was significantly reduced. We also found that Rab8A has a similar function.
Rab10 and Rab8A are new cytoplasmic factors implicated in WPB biogenesis that play a role in generating granules that can rapidly respond to secretagogue.
内皮细胞血管性血友病因子（VWF）介导血小板黏附，并作为凝血因子 VIII 的保护性伴侣。高度多聚化的 VWF 的快速释放特别有助于止血。为了产生这种蛋白质，需要进行精细的生物发生，最终在跨高尔基网络（TGN）中以储存在称为 Weibel-Palade 体（WPB）的分泌颗粒中。如果不能正确形成这些细胞器，可能会导致 VWF 的低分子量多聚体不受控制地分泌。TGN 相关衔接蛋白 AP-1 及其相互作用蛋白网格蛋白、aftiphilin 和 γ-synergin 对于在高尔基器中初始 WPB 的形成以及 VWF 的储存和分泌是必不可少的。
鉴定新的与 VWF 储存和/或分泌相关的蛋白质。
在秀丽隐杆线虫中进行全基因组 RNA 干扰（RNAi）筛选，以鉴定新的 AP-1 遗传相互作用蛋白。
发现小 GTP 酶 Rab10 与 AP-1 在秀丽隐杆线虫中的部分功能丧失发生遗传相互作用。我们在人脐静脉内皮细胞（HUVEC）中研究了 Rab10。我们报告说，Rab10 在高尔基体中富集，WPB 就是在这里形成的，并且在 Rab10 表达被 siRNA 抑制的细胞中，VWF 的分泌发生改变：快速释放的 VWF 量显著减少。我们还发现 Rab8A 具有类似的功能。
Rab10 和 Rab8A 是新的细胞质因子，参与 WPB 的生物发生，在产生能够快速响应分泌激动剂的颗粒方面发挥作用。
