PDF(Pubmed)
Abstract：
Membrane-enclosed transport carriers sort biological molecules between stations in the cell in a dynamic process that is fundamental to the physiology of eukaryotic organisms. While much is known about the formation and release of carriers from specific intracellular membranes, the mechanism of carrier formation from the recycling endosome, a compartment central to cellular signaling, remains to be resolved. In Caenorhabditis elegans, formation of transport carriers from the recycling endosome requires the dynamin-like, Eps15-homology domain (EHD) protein, RME-1, functioning with the Bin/Amphiphysin/Rvs (N-BAR) domain protein, AMPH-1. Here we show, using a free-solution single-particle technique known as burst analysis spectroscopy (BAS), that AMPH-1 alone creates small, tubular-vesicular products from large, unilamellar vesicles by membrane fission. Membrane fission requires the amphipathic H0 helix of AMPH-1 and is slowed in the presence of RME-1. Unexpectedly, AMPH-1-induced membrane fission is stimulated in the presence of GTP. Furthermore, the GTP-stimulated membrane fission activity seen for AMPH-1 is recapitulated by the heterodimeric N-BAR amphiphysin protein from yeast, Rvs161/167p, strongly suggesting that GTP-stimulated membrane fission is a general property of this important class of N-BAR proteins.
摘要：
膜封闭的运输载体在动态过程中对细胞中的站之间的生物分子进行分类，这对于真核生物的生理学至关重要。虽然很多关于载体从特定细胞内膜的形成和释放的知识，从循环内体形成载体的机制，细胞信号的中心隔间，还有待解决。在秀丽隐杆线虫中,从回收内体形成运输载体需要类似于发电机，Eps15同源域（EHD）蛋白，RME-1，与Bin/两栖蛋白/Rvs（N-BAR）结构域蛋白起作用，AMPH-1.在这里我们展示，使用称为爆发分析光谱(BAS)的自由溶液单粒子技术，AMPH-1单独创造小的，大的管状泡状产品，由膜裂变产生的单层囊泡。膜裂变需要AMPH-1的两亲性H0螺旋，并且在RME-1存在下减慢。出乎意料的是,在GTP存在下,AMPH-1诱导的膜裂变被刺激。此外，AMPH-1的GTP刺激的膜裂变活性由酵母的异源二聚体N-BAR两栖类蛋白概括，Rvs161/167p,强烈表明GTP刺激的膜裂变是这类重要的N-BAR蛋白的一般性质。
