Faust, Joseph E.Desai, TanviVerma, AvaniUlengin, IdilSun, Tzu-LinMoss, Tyler J.Betancourt, Miguel A.Huang, Huey W.Lee, TinaMcNew, James A.2015-01-162015-01-162015Faust, Joseph E., Desai, Tanvi, Verma, Avani, et al.. "The Atlastin C-terminal Tail is an Amphipathic Helix that Perturbs Bilayer Structure during Endoplasmic Reticulum Homotypic Fusion." <i>The Journal of Biological Chemistry,</i> (2015) American Society for Biochemistry and Molecular Biology: http://dx.doi.org/10.1074/jbc.M114.601823.https://hdl.handle.net/1911/78925Fusion of tubular membranes is required to form three-way junctions found in reticular subdomains of the endoplasmic reticulum (ER). The large GTPase Atlastin has recently been shown to drive ER membrane fusion and three-way junction formation. The mechanism of Atlastin-mediated membrane fusion is distinct from SNARE-mediated and many details remain unclear. In particular, the role of the amphipathic C-terminal tail of Atlastin is still unknown. We have found that a peptide corresponding to the Atlastin C-terminal tail binds to membranes as a parallel alpha helix, induces bilayer thinning, and increases acyl chain disorder. The function of the C-terminal tail is conserved in human Atlastin. Mutations in the C-terminal tail decrease fusion activity in vitro, but not GTPase activity, and impair Atlastin function in vivo. In the context of unstable lipid bilayers, the requirement for the C-terminal tail is abrogated. These data suggest that the C-terminal tail of Atlastin locally destabilizes bilayers to facilitate membrane fusion.engThis is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by the American Society for Biochemistry and Molecular Biology.Journal articlecell compartmentalizationendoplasmic reticulum (ER)membrane fusionfluorescence resonance energy transfer (FRET)phospholipid vesicleneurodegenerationmembrane structureGTPasehttp://dx.doi.org/10.1074/jbc.M114.601823