Figure 1.

The stalk-pore model of lipid bilayer fusion. (A) and consensus models for class I and class II protein-mediated membrane fusion (B and C). SU and TM are the surface and transmembrane subunits of a fusion protein, respectively. Fusion peptides/domains are colored yellow. The structure in B is the trimeric core of the Simian Immunodeficiency Virus gp41 in a post-fusion conformation. The yellow triangle and arrow represent the position and orientation of the membrane spanning domain and the fusion peptide, respectively. The structure in C is the Dengue Virus E protein fragment in its post-fusion conformation (a monomer is shown for visual clarity). The yellow dashed line and triangle represent the viral membrane-proximal segment and the membrane spanning domain, respectively. Asterisk marks the location of the fusion domain.