5ca8 | pdb_00005ca8
Structures of the yeast dynamin-like GTPase Sey1p in complex with GDP
Structural highlights
FunctionSEY1_CANAL Cooperates with the reticulon proteins and tubule-shaping DP1 family proteins to generate and maintain the structure of the tubular endoplasmic reticulum network. Has GTPase activity, which is required for its function in ER organization (By similarity). Required for virulence and resistance to cycloheximide.[HAMAP-Rule:MF_03109][1] Publication Abstract from PubMedHomotypic 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. Structures of the yeast dynamin-like GTPase Sey1p provide insight into homotypic ER fusion.,Yan L, Sun S, Wang W, Shi J, Hu X, Wang S, Su D, Rao Z, Hu J, Lou Z J Cell Biol. 2015 Sep 14;210(6):961-72. doi: 10.1083/jcb.201502078. PMID:26370501[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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