Open AccessMultivalent Rab interactions determine tether-mediated membrane fusion
Author(s) -
Anna Lürick,
Jieqiong Gao,
Anne Kuhlee,
Erdal Yavavli,
Lars Langemeyer,
Angela Perz,
Stefan Raunser,
Christian Ungermann
Publication year - 2017
Publication title -
molecular biology of the cell
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.463
H-Index - 225
eISSN - 1939-4586
pISSN - 1059-1524
DOI - 10.1091/mbc.e16-11-0764
Subject(s) - rab , tethering , gtpase , biology , lipid bilayer fusion , microbiology and biotechnology , fusion protein , prenylation , fusion , phosphorylation , biochemistry , membrane , recombinant dna , linguistics , philosophy , gene , enzyme
Membrane fusion at endomembranes requires cross-talk between Rab GTPases and tethers to drive SNARE-mediated lipid bilayer mixing. Several tethers have multiple Rab-binding sites with largely untested function. Here we dissected the lysosomal HOPS complex as a tethering complex with just two binding sites for the Rab7-like Ypt7 protein to determine their relevance for fusion. Using tethering and fusion assays combined with HOPS mutants, we show that HOPS-dependent fusion requires both Rab-binding sites, with Vps39 being the stronger Ypt7 interactor than Vps41. The intrinsic amphipathic lipid packaging sensor (ALPS) motif within HOPS Vps41, a target of the vacuolar kinase Yck3, is dispensable for tethering and fusion but can affect tethering if phosphorylated. In combination, our data demonstrate that a multivalent tethering complex uses its two Rab bindings to determine the place of SNARE assembly and thus fusion at endomembranes.