Proposed of model of how a denatured protein can induce membrane hemifusion without proceeding through a stalk intermediate.

<p>The model postulates that denatured proteins (represented as orange randomly shaped curves), and perhaps other amphpathic macromolecules, can induce hemifusion by binding to two membranes (<b>A</b>), accumulating at the membrane-membrane interface (<b>B</b>), and causing a scrambling of lipid molecules at the interface (<b>C</b>) that eventually rearranges into a stable hemifusion diaphragm (<b>D</b>). A curved membrane from a vesicle and a flat membrane are used in the drawings, but the mechanism could apply to membranes with diverse curvatures.