Membrane Fusion Intermediates via Directional and Full Assembly of the SNARE Complex
2012
Hernandez, Javier M. | Stein, Alexander | Behrmann, Elmar | Riedel, Dietmar | Cypionka, Anna | Farsi, Zohreh | Walla, Peter J. | Raunser, Stefan | Jahn, Reinhard
No More Fusion Confusion Biophysical models explain membrane fusion as a sequence of steps—including membrane contact, formation of a fusion stalk (merger of proximal monolayers), development of contact between distal monolayers that may or may not expand (hemifusion), and, finally, rupture of this diaphragm resulting in the opening of a fusion pore. Biological membrane fusion reactions are often driven by so-called SNARE proteins. By using a reconstituted membrane fusion system, Hernandez et al. (p. 1581, published online 31 May) have now been able to correlate precisely the states of SNARE zippering with intermediate structures along the fusion pathway. The results suggest that a tightly docked state, with a membrane distance so close that no proteins fit in between them, represents a critical fusion intermediate as a consequence of SNARE zippering. This intermediate is incompatible with a SNARE-driven stalk or with a ringlike arrangement of SNAREs depicted in most current models of membrane fusion.
显示更多 [+] 显示较少 [-]