SNARE chaperone Sly1 directly mediates close-range vesicle tethering.
J Cell Biol
; 223(6)2024 06 03.
Article
em En
| MEDLINE
| ID: mdl-38478018
ABSTRACT
The essential Golgi protein Sly1 is a member of the Sec1/mammalian Unc-18 (SM) family of SNARE chaperones. Sly1 was originally identified through remarkable gain-of-function alleles that bypass requirements for diverse vesicle tethering factors. Employing genetic analyses and chemically defined reconstitutions of ER-Golgi fusion, we discovered that a loop conserved among Sly1 family members is not only autoinhibitory but also acts as a positive effector. An amphipathic lipid packing sensor (ALPS)-like helix within the loop directly binds high-curvature membranes. Membrane binding is required for relief of Sly1 autoinhibition and also allows Sly1 to directly tether incoming vesicles to the Qa-SNARE on the target organelle. The SLY1-20 mutation bypasses requirements for diverse tethering factors but loses this ability if the tethering activity is impaired. We propose that long-range tethers, including Golgins and multisubunit tethering complexes, hand off vesicles to Sly1, which then tethers at close range to initiate trans-SNARE complex assembly and fusion in the early secretory pathway.
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1
Base de dados:
MEDLINE
Assunto principal:
Saccharomyces cerevisiae
/
Vesículas Citoplasmáticas
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Proteínas de Saccharomyces cerevisiae
Limite:
Animals
Idioma:
En
Ano de publicação:
2024
Tipo de documento:
Article