EHBP1L1 coordinates Rab8 and Bin1 to regulate apical-directed transport in polarized epithelial cells.
EHBP1L1 coordinates Rab8 and Bin1 to regulate apical-directed transport in polarized epithelial cells.
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DOI：
10.1083/jcb.201508086
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发表时间：
2016-02-01
期刊：
影响因子：
--
通讯作者：
Harada A
中科院分区：
文献类型：
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作者：
Nakajo A;Yoshimura S;Togawa H;Kunii M;Iwano T;Izumi A;Noguchi Y;Watanabe A;Goto A;Sato T;Harada A
新的蛋白质EHBP1L1将Rab8与Bin1和Dynamin连接起来，调节上皮细胞的顶端运输。在真核细胞中，高度保守的Rab鸟苷三磷酸酶(GTPase)Rab8在向极化质膜的胞吐过程中起着重要作用。在缺乏Rab8的小鼠小肠细胞中，顶端蛋白被错误地分类为溶酶体。在这项研究中，我们鉴定了一个新的Rab8相互作用蛋白复合体，它包含一个EH结构域结合蛋白1样蛋白1(EHBP1L1)、BIN1/两栖动物蛋白II和Dynamin。生化分析表明，EHBP1L1与GTP负载的Rab8和BIN1直接结合。通过过表达和敲除实验证明了这些复合体在内吞循环隔室(ERC)的空间依赖性。EHBP1L1或BIN1缺失或Dynamin抑制的小肠有机体在溶酶体内显著积聚顶膜蛋白，但不积聚基侧膜蛋白。此外，在EHBP1L1基因缺陷的小鼠中，小肠细胞显示出截短和稀疏的微绒毛，这表明EHBP1L1通过调节顶端运输来维持顶端质膜。综上所述，我们的数据表明EHBP1L1连接了Rab8和BIN1-Dynamin复合体，后者产生膜曲率并切除ERC处的囊泡进行根尖运输。
The novel protein EHBP1L1 links Rab8 to Bin1and dynamin to regulate apical transport in epithelial cells. The highly conserved Rab guanosine triphosphatase (GTPase) Rab8 plays a role in exocytosis toward the polarized plasma membrane in eukaryotic cells. In murine Rab8-deficient small intestine cells, apical proteins are missorted into lysosomes. In this study, we identified a novel Rab8-interacting protein complex containing an EH domain–binding protein 1–like 1 (EHBP1L1), Bin1/amphiphysin II, and dynamin. Biochemical analyses showed that EHBP1L1 directly bound to GTP-loaded Rab8 and Bin1. The spatial dependency of these complexes at the endocytic recycling compartment (ERC) was demonstrated through overexpression and knockdown experiments. EHBP1L1- or Bin1-depleted or dynamin-inhibited small intestine organoids significantly accumulated apical membrane proteins but not basolateral membrane proteins in lysosomes. Furthermore, in EHBP1L1-deficient mice, small intestine cells displayed truncated and sparse microvilli, suggesting that EHBP1L1 maintains the apical plasma membrane by regulating apical transport. In summary, our data demonstrate that EHBP1L1 links Rab8 and the Bin1–dynamin complex, which generates membrane curvature and excises the vesicle at the ERC for apical transport.