Novel secretory vesicle proteins essential for membrane fusion display extracellular-matrix domains
Novel secretory vesicle proteins essential for membrane fusion display extracellular-matrix domains
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DOI：
10.1111/j.1600-0854.2004.00194.x
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发表时间：
2004-07-01
期刊：
影响因子：
4.5
通讯作者：
Cohen, J
中科院分区：
文献类型：
--
作者：
Froissard, M;Keller, AM;Cohen, J
可以在草履虫中获得胞吐突变体，其影响融合机器的组织，通过电子显微镜可见。基因在质膜、胞质或分泌区室中的作用位点可以在这样的突变体中容易地确定。功能互补克隆的胞吐突变体，特别是在分泌室，nd 2 -1和nd 169 -1，这里报道，和以前研究的nd 7 -1，导致发现了一组新的蛋白质，显示PSI和EGF结构域，通常发现在细胞外基质蛋白和跨膜信号。这些蛋白质之一的结构，Nd 2 p，和在基因组Nd 22 p中发现的一个paradox的产物，对应于I型膜受体，通常参与蛋白质和囊泡分选。我们的表征表明，我们已经确定的蛋白质是必需的，以表明存在一个成熟的分泌囊泡的质膜，准备机器融合。我们建议将这种新的受体亚类命名为VEMIF，即参与制备膜融合的囊泡细胞外基质样蛋白。
Exocytotic mutants can be obtained in Paramecium that affect the organization of the fusion machinery, visible by electron microscopy. The site of action of the genes in the plasma membrane, cytosol or secretory compartment can easily be determined in such mutants. Functional complementation cloning of exocytotic mutants specifically affected in the secretory compartment, nd2-1 and nd169-1, reported here, and the previously studied nd7-1, led to the discovery of a set of novel proteins that display PSI and EGF domains, normally found in extracellular matrix proteins and involved in transmembrane signaling. The structure of one of these proteins, Nd2p, and of the product of a paralog found in the genome Nd22p, corresponds to that of type I membrane receptors, generally involved in protein and vesicle sorting. Our characterization suggests that the proteins we have identified are required to indicate the presence of a mature secretory vesicle to the plasma membrane, to prepare the machinery for fusion. We propose to name this novel subclass of receptors VEMIF, for Vesicular Extracellular-Matrix-like proteins Involved in preparing membrane Fusion.