Ugo1p is a multipass transmembrane protein with a single carrier domain required for mitochondrial fusion
Ugo1p is a multipass transmembrane protein with a single carrier domain required for mitochondrial fusion
复制标题
DOI：
10.1111/j.1600-0854.2007.00550.x
复制
发表时间：
2007-05-01
期刊：
影响因子：
4.5
通讯作者：
Shaw, Janet M.
中科院分区：
文献类型：
--
作者：
Coonrod, Emily M.;Karren, Mary Anne;Shaw, Janet M.
线粒体膜外膜蛋白Ugo1与Fzo1p和Mgm1p GTP酶形成复合体，调节酵母中的线粒体融合。Ugo1p包含在线粒体载体蛋白(MCP)中发现的两个假定的载体结构域(PCD)。线粒体载体蛋白是一种多通道跨膜蛋白，能主动地将分子跨线粒体内膜运输。线粒体载体蛋白的运输需要具有相同序列PX(D/E)XX(K/R)的功能载体结构域。这一共识序列中带电残基的突变破坏了运输功能。在这项研究中，我们使用靶向突变来表明Ugo1p PCD2的电荷反转突变，而不是PCD1，破坏了线粒体融合。据报道，Ugo1p是一种单程跨膜蛋白，尽管它含有几个额外的预测跨膜片段。利用蛋白质靶向和膜提取实验相结合的方法，我们提供了Ugo1p含有额外的跨膜区的证据，并且可能是一种多通道跨膜蛋白。这些研究确定PCD2是Ugo1p的一个功能结构域，并为这一重要融合成分的多通道拓扑结构提供了第一个实验证据。
The outer mitochondrial membrane protein Ugo1 forms a complex with the Fzo1p and Mgm1p GTPases that regulates mitochondrial fusion in yeast. Ugo1p contains two putative carrier domains (PCDs) found in mitochondrial carrier proteins (MCPs). Mitochondrial carrier proteins are multipass transmembrane proteins that actively transport molecules across the inner mitochondrial membrane. Mitochondrial carrier protein transport requires functional carrier domains with the consensus sequence PX(D/E)XX(K/R). Mutation of charged residues in this consensus sequence disrupts transport function. In this study, we used targeted mutagenesis to show that charge reversal mutations in Ugo1p PCD2, but not PCD1, disrupt mitochondrial fusion. Ugo1p is reported to be a single-pass transmembrane protein despite the fact that it contains several additional predicted transmembrane segments. Using a combination of protein targeting and membrane extraction experiments, we provide evidence that Ugo1p contains additional transmembrane domains and is likely a multipass transmembrane protein. These studies identify PCD2 as a functional domain of Ugo1p and provide the first experimental evidence for a multipass topology of this essential fusion component.