Pant Saumya, Sharma Mahak, Patel Kruti, Caplan Steve, Carr Chavela M, Grant Barth D
Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, NJ 08854, USA.
Nat Cell Biol. 2009 Dec;11(12):1399-410. doi: 10.1038/ncb1986. Epub 2009 Nov 15.
RME-1/EHD1 (receptor mediated endocytosis/Eps15 homology-domain containing 1) family proteins are key residents of the recycling endosome, which are required for endosome-to-plasma membrane transport in Caenorhabditis elegans and mammals. Recent studies suggest similarities between the RME-1/EHD proteins and the Dynamin GTPase superfamily of mechanochemical pinchases, which promote membrane fission. Here we show that endogenous C. elegans AMPH-1, the only C. elegans member of the Amphiphysin/BIN1 family of BAR (Bin1-Amphiphysin-Rvs161p/167p)-domain-containing proteins, colocalizes with RME-1 on recycling endosomes in vivo, that amph-1-deletion mutants are defective in recycling endosome morphology and function, and that binding of AMPH-1 Asn-Pro-Phe(Asp/Glu) sequences to the RME-1 EH-domain promotes the recycling of transmembrane cargo. We also show a requirement for human BIN1 (also known as Amphiphysin 2) in EHD1-regulated endocytic recycling. In vitro, we find that purified recombinant AMPH-1-RME-1 complexes produce short, coated membrane tubules that are qualitatively distinct from those produced by either protein alone. Our results indicate that AMPH-1 and RME-1 cooperatively regulate endocytic recycling, probably through functions required for the production of cargo carriers that exit the recycling endosome for the cell surface.
RME-1/EHD1（受体介导的内吞作用/含Eps15同源结构域1）家族蛋白是再循环内体的关键驻留蛋白，在秀丽隐杆线虫和哺乳动物中，它们是内体到质膜运输所必需的。最近的研究表明，RME-1/EHD蛋白与促进膜裂变的动力蛋白GTP酶超家族的机械化学解聚酶之间存在相似性。在这里，我们表明，内源性秀丽隐杆线虫AMPH-1是含BAR（Bin1-发动蛋白-Rvs161p/167p）结构域的发动蛋白/BIN1家族在秀丽隐杆线虫中的唯一成员，在体内与RME-1在再循环内体上共定位，amph-1缺失突变体在再循环内体形态和功能上存在缺陷，并且AMPH-1的天冬酰胺-脯氨酸-苯丙氨酸（天冬氨酸/谷氨酸）序列与RME-1的EH结构域结合可促进跨膜货物的再循环。我们还表明，人类BIN1（也称为发动蛋白2）在EHD1调节的内吞再循环中是必需的。在体外，我们发现纯化的重组AMPH-1-RME-1复合物产生短的、有被膜小管，其在性质上与单独由任何一种蛋白产生的小管不同。我们的结果表明，AMPH-1和RME-1协同调节内吞再循环，可能是通过产生从再循环内体输出到细胞表面的货物载体所需的功能来实现的。
