Cargando…
A short region upstream of the yeast vacuolar Qa-SNARE heptad-repeats promotes membrane fusion through enhanced SNARE complex assembly
Whereas SNARE (soluble N-ethylmaleimide–sensitive factor attachment protein receptor) heptad-repeats are well studied, SNAREs also have upstream N-domains of indeterminate function. The assembly of yeast vacuolar SNAREs into complexes for fusion can be studied in chemically defined reactions. Comple...
Autores principales: | , |
---|---|
Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
The American Society for Cell Biology
2017
|
Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5555656/ https://www.ncbi.nlm.nih.gov/pubmed/28637767 http://dx.doi.org/10.1091/mbc.E17-04-0218 |
Sumario: | Whereas SNARE (soluble N-ethylmaleimide–sensitive factor attachment protein receptor) heptad-repeats are well studied, SNAREs also have upstream N-domains of indeterminate function. The assembly of yeast vacuolar SNAREs into complexes for fusion can be studied in chemically defined reactions. Complementary proteoliposomes bearing a Rab:GTP and either the vacuolar R-SNARE or one of the three integrally anchored Q-SNAREs were incubated with the tethering/SM protein complex HOPS and the two other soluble SNAREs (lacking a transmembrane anchor) or their SNARE heptad-repeat domains. Fusion required a transmembrane-anchored R-SNARE on one membrane and an anchored Q-SNARE on the other. The N-domain of the Qb-SNARE was completely dispensable for fusion. Whereas fusion can be promoted by very high concentrations of the Qa-SNARE heptad-repeat domain alone, at physiological concentrations the Qa-SNARE heptad-repeat domain alone has almost no fusion activity. The 181–198 region of Qa, immediately upstream of the SNARE heptad-repeat domain, is required for normal fusion activity with HOPS. This region is needed for normal SNARE complex assembly. |
---|