Munc18-1, exocytotic fusion pore regulation and local membrane anisotropy. 2012

Jernej Jorgačevski, and Robert Zorec
Laboratory of Neuroendocrinology-Molecular Cell Physiology, Faculty of Medicine, University of Ljubljana; Ljubljana, Slovenia.

The release of hormones and neurotransmitters from vesicles can be modified by the regulation of the fusion pore, an aqueous channel that forms upon the fusion of the vesicle membrane with the plasma membrane. However, the mechanisms are unclear. Munc18-1 protein interacts with Syntaxin1 (Synt 1), a member of the SNARE proteins, which plays an important role in exocytosis. It has been shown that Munc18-1 has multiple roles, both in pre- and post-fusion stages of exocytosis. It regulates the traffic of Synt1 to the plasma membrane. By inhibiting the tethering of the vesicle SNARE protein Synaptobrevin 2 (Syb2) solely to Synt1 at the plasma membrane, but favoring the vesicular tethering to the preformed binary cis SNARE complex of Synt1A-SNAP25B, Munc18-1 is tuning vesicle docking and the membrane merger process. Additionally, Munc18-1 affects exocytosis at the post-fusion stage by regulating the fusion pore properties (i.e., dwell-time and fusion pore diameter). Among many possible mechanisms that may regulate the fusion pore, but have never been considered previously, is the influence of Munc18-1 on the membrane anisotropy, which determines the local spontaneous membrane curvature and the architecture of the fusion pore. We here propose that Munc18-1 affects the fusion pore by modulating the dynamic local (re)arrangement of anisotropic membrane components within the highly curved fusion pore nanostructure, to which proteins, lipids or their complexes can participate.

UI MeSH Term Description Entries

Related Publications

Jernej Jorgačevski, and Robert Zorec
December 1992, The Journal of cell biology,
Jernej Jorgačevski, and Robert Zorec
June 2011, The Journal of neuroscience : the official journal of the Society for Neuroscience,
Jernej Jorgačevski, and Robert Zorec
August 2020, Cell stress,
Jernej Jorgačevski, and Robert Zorec
November 2018, FEBS letters,
Jernej Jorgačevski, and Robert Zorec
April 1994, Neuron,
Jernej Jorgačevski, and Robert Zorec
July 2007, Molecular immunology,
Jernej Jorgačevski, and Robert Zorec
October 1992, Biophysical journal,
Jernej Jorgačevski, and Robert Zorec
September 2007, Molecular biology of the cell,
Jernej Jorgačevski, and Robert Zorec
September 2023, Biomolecules,
Jernej Jorgačevski, and Robert Zorec
October 2014, Molecular biology of the cell,
Copied contents to your clipboard!