FIG. 8.

Co-IP of wt and mutated HN proteins with L289A-F. Equal numbers of cells were transfected as indicated. Both wt and L289A-mutated F proteins carry mutations in the cleavage site that render them uncleaved and nonfusogenic. After 16 h, the cells were starved and labeled. The cell surface proteins were biotinylated, and the cells were lysed. The lysate was divided into two aliquots and immunoprecipitated with an anti-F MAb and a mixture of anti-HN MAbs (15, 16) (the first lane in each pair) or with the anti-F MAb alone (the second lane in each pair). (A) Comparison of the co-IP of wt HN by the anti-F MAb through its interaction with wt F and L289A-F (indicated as mutF); (B) comparison of the co-IP of wt HN and several NA-HAd-deficient HN mutants by the anti-F MAb through their interaction with L289A-F (mutF).