2012年9月14日 訊 /生物谷BIOON/ --近日，來自弗萊堡大學(xué)的研究者M(jìn)artin通過研究揭示了線粒體結(jié)構(gòu)的一種新視角,，線粒體是細(xì)胞的能量工廠，是細(xì)胞發(fā)揮功能的能量來源,。細(xì)胞中能量的轉(zhuǎn)化發(fā)生在線粒體的生物膜腔內(nèi),，正常膜結(jié)構(gòu)的缺失可以導(dǎo)致中樞神經(jīng)系統(tǒng)和肌肉的一系列疾病。
2011年,，研究者M(jìn)artin發(fā)現(xiàn)了細(xì)胞內(nèi)膜中的復(fù)雜分子機(jī)器,，如今這項研究中，研究者再次表明,，這種分子機(jī)器不僅僅對于形成線粒體結(jié)構(gòu)特征有作用,，而且對于裝配細(xì)胞外膜也有重要作用。相關(guān)研究成果刊登在了雜志Molecular Biology of the Cell上,。
這項研究中,，研究者所研究的蛋白質(zhì)機(jī)器，對于維持線粒體內(nèi)部經(jīng)典的結(jié)構(gòu)必不可少,；同時研究者將蛋白質(zhì)機(jī)器命名為“線粒體內(nèi)膜組織系統(tǒng)”（ Mitochondrial Inner Membrane Organizing System,，MINOS）。本文研究中,，研究者重點闡述了MINOS在構(gòu)建線粒體結(jié)構(gòu)上的重要性,。而且研究者也發(fā)現(xiàn)了MINOS如何將線粒體中截然不同的膜系統(tǒng)聯(lián)系起來。
膜復(fù)合物SAM和TOM在這個過程中扮演著重要角色,，于是研究者使用隧道成型結(jié)構(gòu)（tunnel-shaped structures）來將蛋白質(zhì)運輸至線粒體中,，并且使蛋白質(zhì)嵌合到外膜上。研究者表示,，MINOS組分Fcj1直接參與到了這個過程中,，這對于細(xì)胞存活非常重要，F(xiàn)cj1的生活可以抑制蛋白質(zhì)組分進(jìn)入到線粒體的外膜中,。
這項研究發(fā)現(xiàn)闡述了分子開關(guān)如何影響線粒體膜裝配控制系統(tǒng)和其功能的連接性,，這會徐為我們更深入地理解線粒體的結(jié)構(gòu)提供新的思路，而且也為我們理解線粒體相關(guān)疾病的分子機(jī)制提供幫助,。（生物谷Bioon.com）
編譯自：Molecular Switches in the Cellular Power Plants: Researchers Discover a New Basic Principle of the Architecture of Mitochondria
doi:10.1091/mbc.E12-04-0295
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Role of MINOS in protein biogenesis of the mitochondrial outer membrane
Maria Bohnerta,b,*, Lena-Sophie Wenza,b,*, Ralf M. Zerbesa,b,*, Susanne E. Horvathe, David A. Strouda,†, Karina von der Malsburga,‡, Judith M. Müllera, Silke Oeljeklausc,d, Inge Perschila, Bettina Warscheidc,d, Agnieszka Chacinskaf, Marten Veenhuisg, Ida J. van der Kleig, Günther Daume, Nils Wiedemanna,c, Thomas Beckera,c, Nikolaus Pfannera,c,§, and Martin van der Laana,c,§
Mitochondria contain two membranes, the outer membrane and the inner membrane with folded cristae. The mitochondrial inner membrane organizing system (MINOS) is a large protein complex required for maintaining inner membrane architecture. MINOS interacts with both preprotein transport machineries of the outer membrane, the translocase of the outer membrane (TOM) and the sorting and assembly machinery (SAM). It is unknown, however, if MINOS plays a role in the biogenesis of outer membrane proteins. We have dissected the interaction of MINOS with TOM and SAM and report that MINOS binds to both translocases independently. MINOS binds to the SAM complex via the conserved polypeptide transport-associated (POTRA) domain of Sam50. Mitochondria lacking mitofilin, the large core subunit of MINOS, are impaired in the biogenesis of β-barrel proteins of the outer membrane, whereas mutant mitochondria lacking any of the other five MINOS subunits import β-barrel proteins like wild-type mitochondria. We show that mitofilin is required at an early stage of β-barrel biogenesis that includes the initial translocation through the TOM complex. We conclude that MINOS interacts with TOM and SAM independently and that the core subunit mitofilin is involved in biogenesis of outer membrane β-barrel proteins
