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The Protein Coat in Membrane Fusion: Lessons from Fission
Author(s) -
Kozlov Michael M.,
Chernomordik Leonid V.
Publication year - 2002
Publication title -
traffic
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.677
H-Index - 130
eISSN - 1600-0854
pISSN - 1398-9219
DOI - 10.1034/j.1600-0854.2002.030403.x
Subject(s) - lipid bilayer fusion , fusion , biophysics , biology , fusion protein , membrane , microbiology and biotechnology , fusion mechanism , membrane protein , biochemistry , philosophy , linguistics , gene , recombinant dna
Multiple cell biological processes involve two opposite rearrangements of membrane configuration, referred to as fusion and fission. While membrane intermediates in protein‐mediated fusion have been studied in some detail, the global force which drives sequential stages of the fusion reaction from early local intermediates to an expanding fusion pore remains unknown. Fusion proceeds via stages, which are analogous but in the opposite direction to that of membrane budding‐off and fission driven by protein coats. On the basis of this analogy, we propose that an interconnected coat formed by membrane‐bound activated fusion proteins surrounding the membrane contact zone generates the driving force for fusion. This fusion protein coat has a strongly curved intrinsic shape opposite to that of the protein coat driving fission. To relieve internal stresses, the fusion protein coat spontaneously bends out of the initial shape of the membrane surface. This bending produces elastic stresses in the underlying lipid bilayer and drives its fusion with the apposing membrane. The hypothesis that ‘bystander’ proteins (i.e. fusion proteins outside the contact zone) generate the driving force for fusion offers a new interpretation for a number of known features of the fusion reaction mediated by the prototype fusion protein, influenza hemagglutinin, and might bring new insights into mechanisms of other fusion reactions.