Human parainfluenza virus type 1 phosphoprotein is constitutively phosphorylated at Ser-120 and Ser-184.
RNA-dependent RNA polymerases of single-stranded, negative-sense RNA viruses comprise a phosphoprotein (P) and a large protein. The constitutive phosphorylation of the P protein in these viruses is highly conserved, yet the functional significance of phosphorylation is enigmatic. To approach this problem, phosphorylation sites were determined in two closely related paramyxovirus P proteins. Sendai virus (SV) is a prototypic paramyxovirus. Previously, using a phosphopeptide mapping technique, the primary constitutive phosphorylation site of SV P protein was mapped to Ser-249. Phosphorylation at Ser-249 is dependent on the presence of Pro-250. Human parainfluenza virus type 1 (HPIV-1) P protein has 66% similarity to SV P protein and its predicted secondary structure is highly similar to that of SV P protein. However, there is no obvious conserved phosphorylation site in HPIV-1 P protein. Using the phosphopeptide mapping strategy, the constitutive phosphorylation sites of HPIV-1 P protein were mapped. The HPIV-1 P protein is primarily phosphorylated at Ser-120. Phosphorylation at Ser-120 is dependent on the presence of Pro-121. It also has a minor phosphorylation site at Ser-184. The sequence at Ser-184 does not match any consensus phosphorylation target site for the known kinases. Significantly, the P proteins from both viruses are constitutively and primarily phosphorylated at one serine and the phosphorylation of that serine is dependent on the presence of a proline on its carboxyl side.
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D000595:Amino Acid Sequence; D017353:Gene Deletion; D006801:Humans; D008969:Molecular Sequence Data; D010222:Parainfluenza Virus 1, Human / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010449:Peptide Mapping; D010750:Phosphoproteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D010768:Phosphoserine / Q000378:metabolism; D010957:Plasmids / Q000235:genetics; D017354:Point Mutation; D018108:Respirovirus / Q000235:genetics / Q000378:metabolism; D012694:Serine / Q000737:chemistry / Q000378:metabolism; D014162:Transfection; D014764:Viral Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*
D010750:Phosphoproteins; D014764:Viral Proteins; C068855:P protein, parainfluenza virus 1; D010768:Phosphoserine; D012694:Serine