Interaction of Sendai viral F, HN, and M proteins with host cytoskeletal and lipid components in Sendai virus-infected BHK cells.

We have studied the interaction of Sendai viral fusion (F), hemagglutinin/neuraminidase (H/N), and matrix (M) proteins with host cytoskeletal and lipid components in Sendai virus-infected BHK cells using two nonionic detergents Triton X-100 (TX-100) and octyl glucoside (OG). Our results show that while M protein acquired resistance to both TX-100 and OG extraction, F and HN exhibited insolubility only to TX-100 but not to OG. Furthermore, in the presence of high salt (1 M NaCl), M, but not F or HN, became TX-100 soluble. Both type I (F) and type II (HN) viral glycoproteins acquired TX-100 insolubility at a late stage during exocytic transport as they acquired endo H resistance. In addition, TX-100 insoluble F and HN exhibited a lighter density compared to TX-100 resistant M by flotation analysis. Using recombinant vaccinia viruses that express Sendai virus HN, F, or M protein individually, we observed that each viral protein (F, HN, or M) was independently capable of acquiring TX-100 insolubility in the absence of other viral components. These results would indicate that while Sendai viral F and HN became bound to TX-100 insoluble lipids, M protein bound ionically to TX-100 insoluble cytoskeletal components and not to TX-100 insoluble lipids.