內(nèi)質(zhì)網(wǎng)對(duì)包括膜的生物發(fā)生,、囊泡運(yùn)輸和蛋白分泌在內(nèi)的很多細(xì)胞功能都很關(guān)鍵，它是一個(gè)由管狀結(jié)構(gòu)構(gòu)成的互聯(lián)的網(wǎng)絡(luò),，遍及真核細(xì)胞,。這一特定結(jié)構(gòu)的維持機(jī)制尚不清楚，盡管依賴于GTP水解的同型膜融合已知是內(nèi)質(zhì)網(wǎng)的生物發(fā)生和維持所必需的,。
現(xiàn)在,，用果蠅所進(jìn)行的一項(xiàng)研究表明，被稱為Atlastin的一種GTP酶（在遺傳性痙攣性截癱中發(fā)生突變的人類Atlastin 1的一個(gè)同源分子）是同型膜融合所必需的,，因而也是內(nèi)質(zhì)網(wǎng)形成所必需的,。（生物谷Bioon.com）
生物谷推薦原始出處：
Nature 460, 978-983 (20 August 2009) | doi:10.1038/nature08280
Homotypic fusion of ER membranes requires the dynamin-like GTPase Atlastin
Genny Orso1,8, Diana Pendin1,8, Song Liu2,8, Jessica Tosetto1,3, Tyler J. Moss2, Joseph E. Faust2, Massimo Micaroni4, Anastasia Egorova5, Andrea Martinuzzi1, James A. McNew2 & Andrea Daga1,6,7
1 Eugenio Medea Scientific Institute, Conegliano 31015, Italy
2 Department of Biochemistry and Cell Biology, Rice University, Houston, Texas 77005, USA
3 Department of Pharmacology, University of Padova, Padova 35131, Italy
4 University of Queensland, Institute for Molecular Bioscience, St Lucia, Brisbane, Queensland 4072, Australia
5 Department of Cell Biology and Oncology, Consorzio "Mario Negri Sud", Santa Maria Imbaro 66030, Italy
6 Dulbecco Telethon Institute, Eugenio Medea Scientific Institute, Padova 35131, Italy
7 Department of Neurology, The David Geffen School of Medicine, University of California, Los Angeles, California 90095, USA
8 These authors contributed equally to this work.
Establishment and maintenance of proper architecture is essential for endoplasmic reticulum (ER) function. Homotypic membrane fusion is required for ER biogenesis and maintenance, and has been shown to depend on GTP hydrolysis. Here we demonstrate that Drosophila Atlastin—the fly homologue of the mammalian GTPase atlastin 1 involved in hereditary spastic paraplegia—localizes on ER membranes and that its loss causes ER fragmentation. Drosophila Atlastin embedded in distinct membranes has the ability to form trans-oligomeric complexes and its overexpression induces enlargement of ER profiles, consistent with excessive fusion of ER membranes. In vitro experiments confirm that Atlastin autonomously drives membrane fusion in a GTP-dependent fashion. In contrast, GTPase-deficient Atlastin is inactive, unable to form trans-oligomeric complexes owing to failure to self-associate, and incapable of promoting fusion in vitro. These results demonstrate that Atlastin mediates membrane tethering and fusion and strongly suggest that it is the GTPase activity that is required for ER homotypic fusion.
