Structures of the yeast dynamin-like GTPase Sey1p provide insight into homotypic ER fusion，Journal of Cell Biology，Published September 14, 2015

Journal of Cell Biology, Published September 14, 2015 // JCB vol. 210 no. 6 961-972 ，doi: 10.1083/jcb.201502078

Structures of the yeast dynamin-like GTPase Sey1p provide insight into homotypic ER fusion

Liming Yan,^1,*，Sha Sun,^2,*，Wei Wang,^1,4， Juanming Shi,²，Xiaoyu Hu,²，Shiyan Wang,⁴，Dan Su,⁵， Zihe Rao,^1,3,6，Junjie Hu,^2,3 and Zhiyong Lou1,⁶

Abstract 

Homotypic membrane fusion of the endoplasmic reticulum is mediated by dynamin-like guanosine triphosphatases (GTPases), which include atlastin (ATL) in metazoans and Sey1p in yeast. In this paper, we determined the crystal structures of the cytosolic domain of Sey1p derived from Candida albicans. The structures reveal a stalk-like, helical bundle domain following the GTPase, which represents a previously unidentified configuration of the dynamin superfamily. This domain is significantly longer than that of ATL and critical for fusion. Sey1p forms a side-by-side dimer in complex with GMP-PNP or GDP/AlF₄^？ but is monomeric with GDP. Surprisingly, Sey1p could mediate fusion without GTP hydrolysis, even though fusion was much more efficient with GTP. Sey1p was able to replace ATL in mammalian cells, and the punctate localization of Sey1p was dependent on its GTPase activity. Despite the common function of fusogenic GTPases, our results reveal unique features of Sey1p.

相关报道：http://www.ibp.cas.cn/kyjz/zxdt/201509/t20150916_4425734.html

文章链接：http://jcb.rupress.org/content/210/6/961.abstract