FIG. 8.

E1* associates with rafts via its fusion peptide. Radiolabeled ectodomains were mixed with 1 mM complete liposomes (A) or buffer (B), and the mixtures were acid treated at pH 5.5 for 3 min at 37°C. The sample for panel A was then floated on a sucrose gradient as described for Fig. 2, and the top four fractions containing liposomes and associated protein were collected and pooled. Aliquots of the panel A and B samples were then, where indicated, extracted for 30 min with either 1% TX-100 on ice or 1% saponin at room temperature. The samples were then immunoprecipitated in the absence of any additional detergent using a polyclonal rabbit antiserum against the SFV envelope proteins (Rab), MAb 1f against E1 residues 85 to 95, or MAb E1a-1 against the acid conformation of E1. A representative example of three experiments is shown. −, no detergent.