Biochemistry & Analytical Biochemistry

Munc18a promotes vesicle tethering in neuronal and non-neuronal fusion

Global Congress on Biochemistry, Glycomics & Amino Acids

December 08-09, 2016 San Antonio, USA

Hao Xu

University of Southern Mississippi, USA

Posters & Accepted Abstracts: Biochem Anal Biochem

Abstract:

Sec1-Munc18 (SM) proteins cooperate with SNAREs {SNAP [soluble NSF (N-ethylmaleimide-sensitive factor) attachment protein] receptors} to promote membrane fusion in eukaryotic cells. Studies of Munc18-1 in neurotransmission suggest that SM proteins accelerate fusion kinetics primarily by activating zippered trans-SNARE complexes. However, Munc18-1 has also been found important in the exocytosis of non-neuronal cells. Here we investigate the function of Munc18a in reconstituted fusion reactions mediated by distinct sets of exocytic SNAREs. We show that Munc18-1 has a new role in promoting proteoliposome tethering. In the three different fusion reactions examined, Munc18a-dependent tethering requires the N-peptide in syntaxins but displays divergence regarding the requirement for SNAP-25-like molecules. In addition, tethering is preserved under inhibitory conditions that abolish both trans-SNARE complex formation and lipid mixing, indicating that Munc18-1 catalyzes tethering in a step preceding trans-SNARE zippering and activation.

Biography :

Email: hao.xu@usm.edu