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A Conserved Acidic Residue in the C-Terminal Flexible Loop of HIV-1 Nef Contributes to the Activity of SERINC5 and CD4 Downregulation

The host transmembrane protein SERINC5 is incorporated into retrovirus particles and inhibits HIV-1 infectivity. The lentiviral Nef protein counteracts SERINC5 by downregulating it from the cell surface and preventing its incorporation into virions. The ability of Nef to antagonize the host factor v...

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Autores principales: Firrito, Claudia, Bertelli, Cinzia, Rosa, Annachiara, Chande, Ajit, Ananth, Swetha, van Dijk, Hannah, Fackler, Oliver T., Stoneham, Charlotte, Singh, Rajendra, Guatelli, John, Pizzato, Massimo
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10057511/
https://www.ncbi.nlm.nih.gov/pubmed/36992361
http://dx.doi.org/10.3390/v15030652
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author Firrito, Claudia
Bertelli, Cinzia
Rosa, Annachiara
Chande, Ajit
Ananth, Swetha
van Dijk, Hannah
Fackler, Oliver T.
Stoneham, Charlotte
Singh, Rajendra
Guatelli, John
Pizzato, Massimo
author_facet Firrito, Claudia
Bertelli, Cinzia
Rosa, Annachiara
Chande, Ajit
Ananth, Swetha
van Dijk, Hannah
Fackler, Oliver T.
Stoneham, Charlotte
Singh, Rajendra
Guatelli, John
Pizzato, Massimo
author_sort Firrito, Claudia
collection PubMed
description The host transmembrane protein SERINC5 is incorporated into retrovirus particles and inhibits HIV-1 infectivity. The lentiviral Nef protein counteracts SERINC5 by downregulating it from the cell surface and preventing its incorporation into virions. The ability of Nef to antagonize the host factor varies in magnitude between different HIV-1 isolates. After having identified a subtype H nef allele unable to promote HIV-1 infectivity in the presence of SERINC5, we investigated the molecular determinants responsible for the defective counteraction of the host factor. Chimeric molecules with a subtype C Nef highly active against SERINC5 were constructed to locate Nef residues crucial for the activity against SERINC5. An Asn at the base of the C-terminal loop of the defective nef allele was found in place of a highly conserved acidic residue (D/E 150). The conversion of Asn to Asp restored the ability of the defective Nef to downregulate SERINC5 and promote HIV-1 infectivity. The substitution was also found to be crucial for the ability of Nef to downregulate CD4, but not for Nef activities that do not rely on the internalization of receptors from the cell surface, suggesting a general implication in promoting clathrin-mediated endocytosis. Accordingly, bimolecular fluorescence complementation revealed that the conserved acidic residue contributes to the recruitment of AP2 by Nef. Altogether, our results confirm that Nef downregulates SERINC5 and CD4 by engaging a similar machinery and indicates that, in addition to the di-leucine motif, other residues in the C-terminal flexible loop are important for the ability of the protein to sustain clathrin-mediated endocytosis.
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spelling pubmed-100575112023-03-30 A Conserved Acidic Residue in the C-Terminal Flexible Loop of HIV-1 Nef Contributes to the Activity of SERINC5 and CD4 Downregulation Firrito, Claudia Bertelli, Cinzia Rosa, Annachiara Chande, Ajit Ananth, Swetha van Dijk, Hannah Fackler, Oliver T. Stoneham, Charlotte Singh, Rajendra Guatelli, John Pizzato, Massimo Viruses Article The host transmembrane protein SERINC5 is incorporated into retrovirus particles and inhibits HIV-1 infectivity. The lentiviral Nef protein counteracts SERINC5 by downregulating it from the cell surface and preventing its incorporation into virions. The ability of Nef to antagonize the host factor varies in magnitude between different HIV-1 isolates. After having identified a subtype H nef allele unable to promote HIV-1 infectivity in the presence of SERINC5, we investigated the molecular determinants responsible for the defective counteraction of the host factor. Chimeric molecules with a subtype C Nef highly active against SERINC5 were constructed to locate Nef residues crucial for the activity against SERINC5. An Asn at the base of the C-terminal loop of the defective nef allele was found in place of a highly conserved acidic residue (D/E 150). The conversion of Asn to Asp restored the ability of the defective Nef to downregulate SERINC5 and promote HIV-1 infectivity. The substitution was also found to be crucial for the ability of Nef to downregulate CD4, but not for Nef activities that do not rely on the internalization of receptors from the cell surface, suggesting a general implication in promoting clathrin-mediated endocytosis. Accordingly, bimolecular fluorescence complementation revealed that the conserved acidic residue contributes to the recruitment of AP2 by Nef. Altogether, our results confirm that Nef downregulates SERINC5 and CD4 by engaging a similar machinery and indicates that, in addition to the di-leucine motif, other residues in the C-terminal flexible loop are important for the ability of the protein to sustain clathrin-mediated endocytosis. MDPI 2023-02-28 /pmc/articles/PMC10057511/ /pubmed/36992361 http://dx.doi.org/10.3390/v15030652 Text en © 2023 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Firrito, Claudia
Bertelli, Cinzia
Rosa, Annachiara
Chande, Ajit
Ananth, Swetha
van Dijk, Hannah
Fackler, Oliver T.
Stoneham, Charlotte
Singh, Rajendra
Guatelli, John
Pizzato, Massimo
A Conserved Acidic Residue in the C-Terminal Flexible Loop of HIV-1 Nef Contributes to the Activity of SERINC5 and CD4 Downregulation
title A Conserved Acidic Residue in the C-Terminal Flexible Loop of HIV-1 Nef Contributes to the Activity of SERINC5 and CD4 Downregulation
title_full A Conserved Acidic Residue in the C-Terminal Flexible Loop of HIV-1 Nef Contributes to the Activity of SERINC5 and CD4 Downregulation
title_fullStr A Conserved Acidic Residue in the C-Terminal Flexible Loop of HIV-1 Nef Contributes to the Activity of SERINC5 and CD4 Downregulation
title_full_unstemmed A Conserved Acidic Residue in the C-Terminal Flexible Loop of HIV-1 Nef Contributes to the Activity of SERINC5 and CD4 Downregulation
title_short A Conserved Acidic Residue in the C-Terminal Flexible Loop of HIV-1 Nef Contributes to the Activity of SERINC5 and CD4 Downregulation
title_sort conserved acidic residue in the c-terminal flexible loop of hiv-1 nef contributes to the activity of serinc5 and cd4 downregulation
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10057511/
https://www.ncbi.nlm.nih.gov/pubmed/36992361
http://dx.doi.org/10.3390/v15030652
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