FIG. 3.

Analysis of Bα-subunit binding by E4orf4 deletion mutants. A series of E4orf4 deletions were produced and expressed as fusion products with HA-MBP, as described in Materials and Methods. Such DNA constructs were lipofected into H1299 cells along with a cDNA expressing a FLAG-tagged human Bα subunit. Aliquots of the cell extracts were immunoprecipitated with anti-HA antibody. After SDS-PAGE and transfer, they were immunoblotted with anti-FLAG antibody to detect associated Bα binding. Other aliquots were separated directly by SDS-PAGE and after transfer were immunoblotted with anti-HA antibody to detect levels of HA-MBP-E4orf4 expression. (A) Map of E4orf4 deletion mutants; (B) Bα-subunit binding; (C) HA-MBP-E4orf4 expression in whole-cell extracts (WCE).