Association of rabies virus nominal phosphoprotein (P) with viral nucleocapsid (NC) is enhanced by phosphorylation of the viral nucleoprotein (N).
We investigated possible role(s) of N protein phosphorylation in the rabies virus replication process. A large amount of P proteins are associated with the viral nucleocapsid (NC) in the infected cell, the amount which was greatly decreased by phosphatase-treatment of the isolated NC, indicating that the phosphate group of N and/or P proteins is essential for their stable association with the NC. Immunoprecipitation studies were performed on the coexpressed normal N or phosphorylation deficient N(S389A) and P proteins, demonstrating that the P protein associated with phosphorylation-deficient NC-like structures was much less in amount than that associated with the wild type NC. Similar results were also obtained with a mutant P protein, PDeltaN19, which lacked the N-terminal 19 amino acids and was capable of binding to the NC-like structures but incapable of forming the RNA-free N-P complexes. Immunoprecipitation studies with mAb #402-13 further suggested that the NC-specific linear 402-13 epitope was exposed even on the P proteins which were associated with the phosphorylation-deficient NC-like structures, but such association was very weak as demonstrated by greatly decreased amounts of coprecipitated NC-like structures. From these results, we assume that the phosphorylation of N protein enhances the association between the 402-13 epitope-positive P protein and the NC probably by stabilizing such P-NC binding.
Toriumi
Harufusa
H
Department of Molecular Microbiology, Graduate School of Pharmaceutical Sciences, Kyoto University, Japan.
Kawai
Akihiko
A
D000911:Antibodies, Monoclonal; D001665:Binding Sites; D047468:Immunoprecipitation; D019590:Nucleocapsid Proteins / Q000737:chemistry / Q000378:metabolism*; D010766:Phosphorylation; D011485:Protein Binding; D011487:Protein Conformation; D011820:Rabies virus / Q000502:physiology*; D014162:Transfection; D014764:Viral Proteins / Q000737:chemistry / Q000378:metabolism*; D019065:Virus Assembly; D014779:Virus Replication
D000911:Antibodies, Monoclonal; D019590:Nucleocapsid Proteins; D014764:Viral Proteins; C087087:nominal phosphoprotein, rabies virus