The Human immunodeficiency virus-1 (HIV-1) accessory protein Vpu modulates numerous proteins, including the host proteins CD4 and BST-2/tetherin. Vpu interacts with the Skp, Cullin, F-Box (SCF) ubiquitin ligase through interactions with the F-Box protein βTrCP (1 and/or 2). This interaction is dependent on phosphorylation of S in Vpu. Mutation of S, or inhibition of the SCF, abolishes most Vpu activity against CD4 and partly reduces activity against BST-2/tetherin. Recently, Vpu has also been reported to interact with the clathrin adapter proteins AP-1 and AP-2, and these interactions were also found to be required for BST-2/tetherin antagonism in an S -dependent manner. In assays where HIV-1 is pseudotyped with gibbon ape leukemia virus (GaLV Env), Vpu has also been found to prevent GaLV Env from being incorporated into viral particles, but the mechanism for this antagonism is not fully understood. To clarify the role of the βTrCPs in Vpu function we used CRISPR/Cas9 to generate a clonal cell line lacking both βTrCP-1 and -2. Vpu activity against CD4 and GaLV Env was abolished in this cell line, and activity against BST-2/tetherin reduced significantly. Mutation of the S residues no longer affected Vpu activity against BST-2/tetherin in this cell line. These data suggest that the primary role of the S residues in antagonism of CD4, GaLV Env, and BST-2/tetherin is to recruit the SCF/βTrCP ubiquitin ligase.
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http://dx.doi.org/10.3390/v10100573 | DOI Listing |
J Virol
April 2024
Laboratory of Molecular Immunology and Infectious Disease, The Joint Graduate School of Veterinary Medicine, Yamaguchi University, Yamaguchi, Japan.
Virology
December 2022
Research Group Pharmaceutical Biotechnology, Faculty of Applied Natural Sciences, TH Köln-University of Applied Sciences, Campusplatz 1, 51379, Leverkusen, Germany. Electronic address:
Viral vectors derived from human immunodeficiency virus type 1 (HIV-1) mediate efficient stable gene transduction. Consequently, these vectors are utilized in gene therapeutic approaches. We here aimed for improving HIV-1 pseudotype vector formation using envelope proteins (Env) of ecotropic murine leukemia virus (MLV) suffering deletions of the R-peptide and further amino acid substitutions in their cytoplasmatic domains.
View Article and Find Full Text PDFBMB Rep
December 2022
Graduate School of New Drug Discovery and Development, Chungnam National University, Daejeon 34134, Korea.
The murine leukemia virus-based semi-retroviral replicating vectors (MuLV-based sRRV) had been developed to improve safety and transgene capacity for cancer gene therapy. However, despite the apparent advantages of the sRRV, improvements in the in vivo transduction efficiency are still required to deliver therapeutic genes efficiently for clinical use. In this study, we established a gibbon ape leukemia virus (GaLV) envelopepseudotyped semi-replication-competent retrovirus vector system (spRRV) which is composed of two transcomplementing replication-defective retroviral vectors termed MuLV-Gag-Pol and GaLV-Env.
View Article and Find Full Text PDFViruses
April 2022
Department of Molecular Microbiology and Immunology, University of Missouri, School of Medicine and the Christopher S. Bond Life Sciences Center, Columbia, MO 65211, USA.
HIV-1 Vpu targets the host cell proteins CD4 and BST-2/Tetherin for degradation, ultimately resulting in enhanced virus spread and host immune evasion. The discovery and characterization of small molecules that antagonize Vpu would further elucidate the contribution of Vpu to pathogenesis and lay the foundation for the study of a new class of novel HIV-1 therapeutics. To identify novel compounds that block Vpu activity, we have developed a cell-based ‘gain of function’ assay that produces a positive signal in response to Vpu inhibition.
View Article and Find Full Text PDFViruses
July 2021
Research Department Cell and Gene Therapy, Department of Stem Cell Transplantation, University Medical Center Hamburg-Eppendorf (UKE), 20246 Hamburg, Germany.
The Gibbon Ape Leukemia Virus envelope protein (GALV-Env) mediates efficient transduction of human cells, particularly primary B and T lymphocytes, and is therefore of great interest in gene therapy. Using internal domains from murine leukemia viruses (MLV), chimeric GALV-Env proteins such as GALV-C were derived, which allow pseudotyping of lentiviral vectors. In order to improve expression efficiency and vector titers, we developed a codon-optimized (co) variant of GALV-C (coGALV-Env).
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