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Publication Abstract from PubMed

Membrane fusion at the vacuole, the lysosome equivalent in yeast, requires the HOPS tethering complex, which is recruited by the Rab7 GTPase Ypt7. HOPS provides a template for the assembly of SNAREs and thus likely confers fusion at a distinct position on vacu-oles. Five of the six subunits in HOPS have a similar domain prediction with strong simi-larity to COPII subunits and nuclear porins. Here, we show that Vps18 indeed has a 7-bladed beta-propeller as its N-terminal domain by revealing its structure at 2.14 Angstroem. The Vps18 N-terminal domain can interact with the N-terminal part of Vps11 and also binds to lipids. Although deletion of the Vps18 N-terminal domain does not preclude HOPS assembly, as revealed by negative stain elec-tron microscopy, the complex is instable and cannot support membrane fusion in vitro. We thus conclude that the beta-propeller of Vps18 is required for HOPS stability and function, and that it can serve as a starting point for further structural analyses of the HOPS tethering complex.

Structural identification of the VPS18 beta-propeller reveals a critical role in the hops complex stability and function.,Behrmann H, Lurick A, Kuhlee A, Balderhaar HK, Brocker C, Kummel D, Engelbrecht-Vandre S, Gohlke U, Raunser S, Heinemann U, Ungermann C J Biol Chem. 2014 Oct 16. pii: jbc.M114.602714. PMID:25324549^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.