tetano
Editor, Senior Moderator
PLoS One. 2015 Apr 13;10(4):e0118477. doi: 10.1371/journal.pone.0118477. eCollection 2015.
[h=1]The Ubiquitination of the Influenza A Virus PB1-F2 Protein Is Crucial for Its Biological Function.[/h] Ko??k I[SUP]1[/SUP], Pr?znovsk? M[SUP]1[/SUP], Ko??kov? M[SUP]1[/SUP], Bobi?ov? Z[SUP]1[/SUP], Holl? J[SUP]1[/SUP], Varečkov? E[SUP]1[/SUP], Kostolansk? F[SUP]1[/SUP], Russ G[SUP]1[/SUP].
[h=3]Author information[/h]
[h=3]Abstract[/h] The aim of the present study was to identify what influences the short half-life of the influenza A virus PB1-F2 protein and whether a prolonged half-life affects the properties of this molecule. We hypothesized that the short half-life of PB1-F2 could conceal the phenotype of the protein. Because proteasome degradation might be involved in PB1-F2 degradation, we focused on ubiquitination, a common label for proteasome targeting. A cluster of lysine residues was demonstrated as an ubiquitination acceptor site in evolutionary and functionally distinct proteins. The PB1-F2 sequence alignment revealed a cluster of lysines on the carboxy terminal end of PB1-F2 in almost all of the GenBank sequences available to date. Using a proximity ligation assay, we identified ubiquitination as a novel posttranslational modification of PB1-F2. Changing the lysines at positions 73, 78, and 85 to arginines suppressed the ubiquitination of A/Puerto Rico/8/1934 (H1N1)-derived PB1-F2. The mutation of the C-terminal lysine residue cluster positively affected the overall expression levels of avian A/Honk Kong/156/1997 (H5N1)- and mammalian A/Puerto Rico/8/1934 (H1N1)-derived PB1-F2. Moreover, increased PB1-F2 copy numbers strengthened the functions of this virus in the infected cells. The results of a minigenome luciferase reporter assay revealed an enhancement of viral RNA-dependent RNA polymerase activity in the presence of stabilized PB1-F2, regardless of viral origin. IFNβ antagonism was enhanced in 293T cells transfected with a plasmid expressing stabilized K→R mutant variants of PB1-F2. Compared with PB1-F2 wt, the loss of ubiquitination enhanced the antibody response after DNA vaccination. In summary, we revealed that PB1-F2 is an ubiquitinated IAV protein, and this posttranslational modification plays a central role in the regulation of the biological functions of this protein.
PMID: 25866881 [PubMed - in process]
[h=1]The Ubiquitination of the Influenza A Virus PB1-F2 Protein Is Crucial for Its Biological Function.[/h] Ko??k I[SUP]1[/SUP], Pr?znovsk? M[SUP]1[/SUP], Ko??kov? M[SUP]1[/SUP], Bobi?ov? Z[SUP]1[/SUP], Holl? J[SUP]1[/SUP], Varečkov? E[SUP]1[/SUP], Kostolansk? F[SUP]1[/SUP], Russ G[SUP]1[/SUP].
[h=3]Author information[/h]
[h=3]Abstract[/h] The aim of the present study was to identify what influences the short half-life of the influenza A virus PB1-F2 protein and whether a prolonged half-life affects the properties of this molecule. We hypothesized that the short half-life of PB1-F2 could conceal the phenotype of the protein. Because proteasome degradation might be involved in PB1-F2 degradation, we focused on ubiquitination, a common label for proteasome targeting. A cluster of lysine residues was demonstrated as an ubiquitination acceptor site in evolutionary and functionally distinct proteins. The PB1-F2 sequence alignment revealed a cluster of lysines on the carboxy terminal end of PB1-F2 in almost all of the GenBank sequences available to date. Using a proximity ligation assay, we identified ubiquitination as a novel posttranslational modification of PB1-F2. Changing the lysines at positions 73, 78, and 85 to arginines suppressed the ubiquitination of A/Puerto Rico/8/1934 (H1N1)-derived PB1-F2. The mutation of the C-terminal lysine residue cluster positively affected the overall expression levels of avian A/Honk Kong/156/1997 (H5N1)- and mammalian A/Puerto Rico/8/1934 (H1N1)-derived PB1-F2. Moreover, increased PB1-F2 copy numbers strengthened the functions of this virus in the infected cells. The results of a minigenome luciferase reporter assay revealed an enhancement of viral RNA-dependent RNA polymerase activity in the presence of stabilized PB1-F2, regardless of viral origin. IFNβ antagonism was enhanced in 293T cells transfected with a plasmid expressing stabilized K→R mutant variants of PB1-F2. Compared with PB1-F2 wt, the loss of ubiquitination enhanced the antibody response after DNA vaccination. In summary, we revealed that PB1-F2 is an ubiquitinated IAV protein, and this posttranslational modification plays a central role in the regulation of the biological functions of this protein.
PMID: 25866881 [PubMed - in process]