Sec17p and HOPS, in Distinct SNARE Complexes, Mediate SNARE Complex Disruption or Assembly for Fusion

Overview

Journal EMBO J

Specialties Biotechnology
Molecular Biology

Date 2005 May 13

PMID 15889152

Citations 71

Authors

Kevin M Collins

Naomi L Thorngren

Rutilio A Fratti

William T Wickner

Affiliations

Soon will be listed here.

Abstract

SNARE functions during membrane docking and fusion are regulated by Sec1/Munc18 (SM) chaperones and Rab/Ypt GTPase effectors. These functions for yeast vacuole fusion are combined in the six-subunit HOPS complex. HOPS facilitates Ypt7p nucleotide exchange, is a Ypt7p effector, and contains an SM protein. We have dissected the associations and requirements for HOPS, Ypt7p, and Sec17/18p during SNARE complex assembly. Vacuole SNARE complexes bind either Sec17p or the HOPS complex, but not both. Sec17p and its co-chaperone Sec18p disassemble SNARE complexes. Ypt7p regulates the reassembly of unpaired SNAREs with each other and with HOPS, forming HOPS.SNARE complexes prior to fusion. After HOPS.SNARE assembly, lipid rearrangements are still required for vacuole content mixing. Thus, Sec17p and HOPS have mutually exclusive interactions with vacuole SNAREs to mediate disruption of SNARE complexes or their assembly for docking and fusion. Sec17p may displace HOPS from SNAREs to permit subsequent rounds of fusion.

Citing Articles

Membrane fusion reactions limited by defective SNARE zippering or stiff lipid fatty acyl composition have distinct requirements for Sec17, Sec18, and adenine nucleotide.

Lopes K, Orr A, Wickner W bioRxiv. 2024; .

PMID: 39605500 PMC: 11601375. DOI: 10.1101/2024.11.15.623832.

After their membrane assembly, Sec18 (NSF) and Sec17 (SNAP) promote membrane fusion.

Song H, Lopes K, Orr A, Wickner W Mol Biol Cell. 2024; 35(12):ar150.

PMID: 39475713 PMC: 11656465. DOI: 10.1091/mbc.E24-10-0439.

Loss of the HOPS complex disrupts early-to-late endosome transition, impairs endosomal recycling and induces accumulation of amphisomes.

van der Beek J, de Heus C, Sanza P, Liv N, Klumperman J Mol Biol Cell. 2024; 35(3):ar40.

PMID: 38198575 PMC: 10916860. DOI: 10.1091/mbc.E23-08-0328.

MARCKS Effector Domain, a reversible lipid ligand, illuminates late stages of membrane fusion.

Orr A, Wickner W Mol Biol Cell. 2023; 34(12):ar123.

PMID: 37672336 PMC: 10846624. DOI: 10.1091/mbc.E23-06-0228.

SNARE Proteins in Synaptic Vesicle Fusion.

Palfreyman M, West S, Jorgensen E Adv Neurobiol. 2023; 33:63-118.

PMID: 37615864 DOI: 10.1007/978-3-031-34229-5_4.

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