Cell membranes protein machine role

One criterion for a bona fide membrane-fusion protein is that membrane fusion can be reconstituted by transfection of the candidate fusion protein into nonfusing cells or by reconstitution into lipid vesicles (White, 1990 White, 1992 White and Blobel, 1989). Transfection of meltrin a into fibroblasts did not lead to an increase in cell fusion (Yagami-Hiromasa et al., 1995). Clearly, failure to reconstitute fusion does not rule out a role in fusion because the cellular fusion machinery may be more complex than viral fusion proteins. Muscle cells might contain other proteins that are required for meltrin a to promote membrane fusion but that are not expressed or active in fibroblasts. Ultimately, the identity of a bona fide cell-cell fusion protein or protein machine will only be determined by reconstituting membrane fusion with defined components. In the interim, it will be important to more accurately understand the roles of meltrin a and fertilin in the cascade of steps that result in membrane fusion and thereby perhaps distinguish between a direct and indirect role in fusion. 

The Essential Role of Protein Machines Within the Cell Membrane... 

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