Inhibition of apoptosis and NF-κB activation by vaccinia protein N1 occur via distinct binding surfaces and make different contributions to virulence.
Vaccinia virus (VACV) protein N1 is an intracellular virulence factor and belongs to a family of VACV B-cell lymphoma (Bcl)-2-like proteins whose members inhibit apoptosis or activation of pro-inflammatory transcription factors, such as interferon (IFN) regulatory factor-3 (IRF-3) and nuclear factor...
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| Format: | Article |
| Language: | English |
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Public Library of Science (PLoS)
2011-12-01
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| Series: | PLoS Pathogens |
| Online Access: | https://journals.plos.org/plospathogens/article/file?id=10.1371/journal.ppat.1002430&type=printable |
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| _version_ | 1849332809411330048 |
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| author | Carlos Maluquer de Motes Samantha Cooray Hongwei Ren Gabriel M F Almeida Kieran McGourty Mohammad W Bahar David I Stuart Jonathan M Grimes Stephen C Graham Geoffrey L Smith |
| author_facet | Carlos Maluquer de Motes Samantha Cooray Hongwei Ren Gabriel M F Almeida Kieran McGourty Mohammad W Bahar David I Stuart Jonathan M Grimes Stephen C Graham Geoffrey L Smith |
| author_sort | Carlos Maluquer de Motes |
| collection | DOAJ |
| description | Vaccinia virus (VACV) protein N1 is an intracellular virulence factor and belongs to a family of VACV B-cell lymphoma (Bcl)-2-like proteins whose members inhibit apoptosis or activation of pro-inflammatory transcription factors, such as interferon (IFN) regulatory factor-3 (IRF-3) and nuclear factor-κB (NF-κB). Unusually, N1 inhibits both apoptosis and NF-κB activation. To understand how N1 exerts these different functions, we have mutated residues in the Bcl-2-like surface groove and at the interface used to form N1 homodimers. Mutagenesis of the surface groove abolished only the N1 anti-apoptotic activity and protein crystallography showed these mutants differed from wild-type N1 only at the site of mutation. Conversely, mutagenesis of the dimer interface converted N1 to a monomer and affected only inhibition of NF-κB activation. Collectively, these data show that N1 inhibits pro-inflammatory and pro-apoptotic signalling using independent surfaces of the protein. To determine the relative contribution of each activity to virus virulence, mutant N1 alleles were introduced into a VACV strain lacking N1 and the virulence of these viruses was analysed after intradermal and intranasal inoculation in mice. In both models, VACV containing a mutant N1 unable to inhibit apoptosis had similar virulence to wild-type virus, whereas VACV containing a mutant N1 impaired for NF-κB inhibition induced an attenuated infection similar to that of the N1-deleted virus. This indicates that anti-apoptotic activity of N1 does not drive virulence in these in vivo models, and highlights the importance of pro-inflammatory signalling in the immune response against viral infections. |
| format | Article |
| id | doaj-art-fa70d7ce667e4cd4885cdf6480649206 |
| institution | Kabale University |
| issn | 1553-7366 1553-7374 |
| language | English |
| publishDate | 2011-12-01 |
| publisher | Public Library of Science (PLoS) |
| record_format | Article |
| series | PLoS Pathogens |
| spelling | doaj-art-fa70d7ce667e4cd4885cdf64806492062025-08-20T03:46:05ZengPublic Library of Science (PLoS)PLoS Pathogens1553-73661553-73742011-12-01712e100243010.1371/journal.ppat.1002430Inhibition of apoptosis and NF-κB activation by vaccinia protein N1 occur via distinct binding surfaces and make different contributions to virulence.Carlos Maluquer de MotesSamantha CoorayHongwei RenGabriel M F AlmeidaKieran McGourtyMohammad W BaharDavid I StuartJonathan M GrimesStephen C GrahamGeoffrey L SmithVaccinia virus (VACV) protein N1 is an intracellular virulence factor and belongs to a family of VACV B-cell lymphoma (Bcl)-2-like proteins whose members inhibit apoptosis or activation of pro-inflammatory transcription factors, such as interferon (IFN) regulatory factor-3 (IRF-3) and nuclear factor-κB (NF-κB). Unusually, N1 inhibits both apoptosis and NF-κB activation. To understand how N1 exerts these different functions, we have mutated residues in the Bcl-2-like surface groove and at the interface used to form N1 homodimers. Mutagenesis of the surface groove abolished only the N1 anti-apoptotic activity and protein crystallography showed these mutants differed from wild-type N1 only at the site of mutation. Conversely, mutagenesis of the dimer interface converted N1 to a monomer and affected only inhibition of NF-κB activation. Collectively, these data show that N1 inhibits pro-inflammatory and pro-apoptotic signalling using independent surfaces of the protein. To determine the relative contribution of each activity to virus virulence, mutant N1 alleles were introduced into a VACV strain lacking N1 and the virulence of these viruses was analysed after intradermal and intranasal inoculation in mice. In both models, VACV containing a mutant N1 unable to inhibit apoptosis had similar virulence to wild-type virus, whereas VACV containing a mutant N1 impaired for NF-κB inhibition induced an attenuated infection similar to that of the N1-deleted virus. This indicates that anti-apoptotic activity of N1 does not drive virulence in these in vivo models, and highlights the importance of pro-inflammatory signalling in the immune response against viral infections.https://journals.plos.org/plospathogens/article/file?id=10.1371/journal.ppat.1002430&type=printable |
| spellingShingle | Carlos Maluquer de Motes Samantha Cooray Hongwei Ren Gabriel M F Almeida Kieran McGourty Mohammad W Bahar David I Stuart Jonathan M Grimes Stephen C Graham Geoffrey L Smith Inhibition of apoptosis and NF-κB activation by vaccinia protein N1 occur via distinct binding surfaces and make different contributions to virulence. PLoS Pathogens |
| title | Inhibition of apoptosis and NF-κB activation by vaccinia protein N1 occur via distinct binding surfaces and make different contributions to virulence. |
| title_full | Inhibition of apoptosis and NF-κB activation by vaccinia protein N1 occur via distinct binding surfaces and make different contributions to virulence. |
| title_fullStr | Inhibition of apoptosis and NF-κB activation by vaccinia protein N1 occur via distinct binding surfaces and make different contributions to virulence. |
| title_full_unstemmed | Inhibition of apoptosis and NF-κB activation by vaccinia protein N1 occur via distinct binding surfaces and make different contributions to virulence. |
| title_short | Inhibition of apoptosis and NF-κB activation by vaccinia protein N1 occur via distinct binding surfaces and make different contributions to virulence. |
| title_sort | inhibition of apoptosis and nf κb activation by vaccinia protein n1 occur via distinct binding surfaces and make different contributions to virulence |
| url | https://journals.plos.org/plospathogens/article/file?id=10.1371/journal.ppat.1002430&type=printable |
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