iScience
Volume 25, Issue 7, 15 July 2022, 104506
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Article
Interspecies complementation identifies a pathway to assemble SNAREs

https://doi.org/10.1016/j.isci.2022.104506Get rights and content
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Highlights

  • Interspecies complementation identifies interactions between SM and SNARE proteins

  • Synaptic transmission requires UNC-18 to interact with SNARE and Habc domains

  • The Habc-SM interaction can be partially bypassed by an open form of UNC-18

  • Yeast SM and SNARE proteins can provide rescue of synaptic transmission

Summary

Unc18 and SNARE proteins form the core of the membrane fusion complex at synapses. To understand the functional interactions within the core machinery, we adopted an “interspecies complementation” approach in Caenorhabditis elegans. Substitutions of individual SNAREs and Unc18 proteins with those from yeast fail to rescue fusion. However, synaptic transmission could be restored in worm-yeast chimeras when two key interfaces were present: an Habc-Unc18 contact site and an Unc18-SNARE motif contact site. A constitutively open form of Unc18 bypasses the requirement for the Habc-Unc18 interface. These data suggest that the Habc domain of syntaxin is required for Unc18 to adopt an open conformation; open Unc18 then templates SNARE complex formation. Finally, we demonstrate that the SNARE and Unc18 machinery in the nematode C. elegans can be replaced by yeast proteins and still carry out synaptic transmission, pointing to the deep evolutionary conservation of these two interfaces.

Subject areas

Biological sciences
Molecular biology
Neuroscience
Molecular neuroscience
Cell biology
Functional aspects of cell biology

Data and code availability

  • All data reported in the paper will be shared by the lead contact upon request.

  • This paper does not report any original code.

  • Additional information needed to reanalyze the data in this paper is available from the lead contact.

Cited by (0)

2

These authors contributed equally

3

Lead contact