Ykt6 functionally overlaps with vacuolar and exocytic R-SNAREs in the yeast Saccharomyces cerevisiae

Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved..

The soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex forms a 4-helix coiled-coil bundle consisting of 16 layers of interacting side chains upon membrane fusion. The central layer (layer 0) is highly conserved and comprises three glutamines (Q) and one arginine (R), and thus SNAREs are classified into Qa-, Qb-, Qc-, and R-SNAREs. Homotypic vacuolar fusion in Saccharomyces cerevisiae requires the SNAREs Vam3 (Qa), Vti1 (Qb), Vam7 (Qc), and Nyv1 (R). However, the yeast strain lacking NYV1 (nyv1Δ) shows no vacuole fragmentation, whereas the vam3Δ and vam7Δ strains display fragmented vacuoles. Here, we provide genetic evidence that the R-SNAREs Ykt6 and Nyv1 are functionally redundant in vacuole homotypic fusion in vivo using a newly isolated ykt6 mutant. We observed the ykt6-104 mutant showed no defect in vacuole morphology, but the ykt6-104 nyv1Δ double mutant had highly fragmented vacuoles. Furthermore, we show the defect in homotypic vacuole fusion caused by the vam7-Q284R mutation was compensated by the nyv1-R192Q or ykt6-R165Q mutations, which maintained the 3Q:1R ratio in the layer 0 of the SNARE complex, indicating that Nyv1 is exchangeable with Ykt6 in the vacuole SNARE complex. Unexpectedly, we found Ykt6 assembled with exocytic Q-SNAREs when the intrinsic exocytic R-SNAREs Snc1 and its paralog Snc2 lose their ability to assemble into the exocytic SNARE complex. These results suggest that Ykt6 may serve as a backup when other R-SNAREs become dysfunctional and that this flexible assembly of SNARE complexes may help cells maintain the robustness of the vesicular transport network.

Medienart:

E-Artikel

Erscheinungsjahr:

2024

Erschienen:

2024

Enthalten in:

Zur Gesamtaufnahme - year:2024

Enthalten in:

The Journal of biological chemistry - (2024) vom: 06. Apr., Seite 107274

Sprache:

Englisch

Beteiligte Personen:

Watanabe, Hayate [VerfasserIn]
Urano, Shingo [VerfasserIn]
Kikuchi, Nozomi [VerfasserIn]
Kubo, Yurika [VerfasserIn]
Kikuchi, Ayumi [VerfasserIn]
Gomi, Katsuya [VerfasserIn]
Shintani, Takahiro [VerfasserIn]

Links:

Volltext

Themen:

Autophagy
Journal Article
Membrane fusion
Membrane trafficking
Plasma membrane
SNARE proteins
Saccharomyces cerevisiae
Vacuole

Anmerkungen:

Date Revised 08.04.2024

published: Print-Electronic

Citation Status Publisher

doi:

10.1016/j.jbc.2024.107274

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM370781554