VIRUS-CELL AND CELL-CELL FUSION

Significant progress has been made in elucidating the mechanisms of vi ral membrane fusion proteins; both those that function at low, as well as those that function at neutral, pH. For many viral fusion proteins evidence now suggests that a triggered conformational change that exp oses a previously cryptic fusion peptide, along with a rearrangement o f the fusion protein oligomer, allows the fusion peptide to gain acces s to the target bilayer and thus initiate the fusion reaction. Althoug h the topologically equivalent process of cell-cell fusion is less wel l understood, several cell surface proteins, including members of the newly described ADAM gene family, have emerged as candidate adhesion/f usion proteins.