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Science. 2009 Jan 23;323(5913):474-7. doi: 10.1126/science.1161748.

Membrane fusion: grappling with SNARE and SM proteins.

Author information

1
Department of Cellular and Molecular Physiology, Stanford University, Palo Alto, CA 94304, USA. tcs1@stanford.edu

Abstract

The two universally required components of the intracellular membrane fusion machinery, SNARE and SM (Sec1/Munc18-like) proteins, play complementary roles in fusion. Vesicular and target membrane-localized SNARE proteins zipper up into an alpha-helical bundle that pulls the two membranes tightly together to exert the force required for fusion. SM proteins, shaped like clasps, bind to trans-SNARE complexes to direct their fusogenic action. Individual fusion reactions are executed by distinct combinations of SNARE and SM proteins to ensure specificity, and are controlled by regulators that embed the SM-SNARE fusion machinery into a physiological context. This regulation is spectacularly apparent in the exquisite speed and precision of synaptic exocytosis, where synaptotagmin (the calcium-ion sensor for fusion) cooperates with complexin (the clamp activator) to control the precisely timed release of neurotransmitters that initiates synaptic transmission and underlies brain function.

PMID:
19164740
PMCID:
PMC3736821
DOI:
10.1126/science.1161748
[Indexed for MEDLINE]
Free PMC Article

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