Defined Subunit Arrangement and Rab Interactions Are Required for Functionality of the HOPS Tethering Complex

Autor(en): Ostrowicz, Clemens W.
Broecker, Cornelia
Ahnert, Franziska
Nordmann, Mirjana
Lachmann, Jens
Peplowska, Karolina
Perz, Angela
Auffarth, Kathrin
Engelbrecht-Vandre, Siegfried
Ungermann, Christian 
Stichwörter: Cell Biology; CORVET; DOCKING; DOMAIN; GTPASE; HOPS; MEMBRANE-FUSION; NUCLEOTIDE EXCHANGE; PROTEIN-TRANSPORT; PURIFICATION; Rab-GTPase; SNARE CHAPERONES; SYSTEM; tethering; vacuole; Vps39; Vps41; YEAST VACUOLE FUSION
Erscheinungsdatum: 2010
Herausgeber: WILEY-BLACKWELL
Journal: TRAFFIC
Volumen: 11
Ausgabe: 10
Startseite: 1334
Seitenende: 1346
Zusammenfassung: 
Within the endomembrane system of eukaryotic cells, multisubunit tethering complexes together with their corresponding Rab-GTPases coordinate vesicle tethering and fusion. Here, we present evidence that two homologous hexameric tethering complexes, the endosomal CORVET (Class C core vacuole/endosome transport) and the vacuolar HOPS (homotypic vacuole fusion and protein sorting) complex, have similar subunit topologies. Both complexes contain two Rab-binding proteins at one end, and the Sec1/Munc18-like Vps33 at the opposite side, suggesting a model on membrane bridging via Rab-GTP and SNARE binding. In agreement, HOPS activity can be reconstituted using purified subcomplexes containing the Rab and Vps33 module, but requires all six subunits for activity. At the center of HOPS and CORVET, the class C proteins Vps11 and Vps18 connect the two parts, and Vps11 binds both HOPS Vps39 and CORVET Vps3 via the same binding site. As HOPS Vps39 is also found at endosomes, our data thus suggest that these tethering complexes follow defined but distinct assembly pathways, and may undergo transition by simple subunit interchange.
ISSN: 13989219
DOI: 10.1111/j.1600-0854.2010.01097.x

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