Proteasome inhibition interferes with Gag polyprotein processing, release, and maturation of HIV-1 and HIV-2

Schubert, Ulrich S.; Ott, David E.; Chertova, Elena; Welker, Reinhold; Tessmer, Uwe; Princiotta, Michael F.; Bennink, Jack R.; Kräusslich, Hans‐Georg; Yewdell, Jonathan W.

doi:10.1073/pnas.97.24.13057

Cited by 308 publications

(334 citation statements)

References 25 publications

Supporting

Mentioning

298

Contrasting

Order By: Relevance

“…However, Tsg101 UEV motif binds also to the P(T͞S)AP motif in the L domain of HIV-1 Gag polypeptide, and the crystal structure analysis revealed that the UEV domain can bind both Ub and PTAP peptide simultaneously (48). The observation that ISG15 interferes with ubiquitination of Gag and consequent release of virus particles correlates with the previous observation, which showed the inhibition of HIV-1 release in the presence of proteasome inhibitors (49).…”

Section: Discussionsupporting

confidence: 76%

Innate antiviral response targets HIV-1 release by the induction of ubiquitin-like protein ISG15

Okumura

Pitha-Rowe

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

318

277

View full text Add to dashboard Cite

The goal of this study was to elucidate the molecular mechanism by which type I IFN inhibits assembly and release of HIV-1 virions. Our study revealed that ISG15 was one of the first recognized ISGs (4). ISG15 is covalently conjugated to targeted proteins through a series of steps similar to ubiquitin conjugation. The ISG15 activating enzyme is ubiquitin E1 like protein (UBE1L), and the major E2 enzyme for ubiquitin conjugation, UbcH8, also recognizes ISG15 (5). An ISG15-specific ligase E3 has not yet been identified, but the IFN-induced Ub E3-like enzymes Rsp5 and CEB1͞Hc5 may function in ISG15 conjugation (6, 7). Like Ub (8), ISG15 is removed from conjugated proteins by an ISG15-specific protease, UBP43 (9). Interestingly, type I IFN stimulates expression not only of ISG15 but also UBEL1, UbcH8, and UBP43 (3, 10) and markedly increases ISG15 conjugation. ISG15 targets a large number of cellular proteins (7); however, modification by ISG15 does not typically cause substrate degradation (11).Ub is a central cellular regulator (12), and Ub-mediated proteolysis plays a regulatory role in the immune system (13). In general, polyubiquitination targets proteins toward 26S protease-associated degradation, whereas monoubiquitination is a signal for internalization and vesicle sorting. However, whereas polyubiquitination on lysine 43 targets proteins for degradation, lysine 63 polyubiquitination is a signal for kinase activation. Many viruses modulate the Ub-proteasome pathway to alter cellular signaling and the antiviral response (14, 15). HIV-1 uses ubiquitination at two steps of its replication cycle. First, HIV-1-encoded protein Vif targets cellular cytidine deaminase APOBEC3G for Ub mediated degradation, thus preventing APOBEC3G incorporation into viral particles and deamination of the viral genome during reverse transcription (16-18). Vif itself is monoubiquitinated and this may help its recruitment to the site of viral assembly (19). Second, ubiquitination of Gag by Ub ligase Nedd4.1 is critical for assembly and release of virions from infected cells (20). HIV-1 assembly is driven by the Gag poly protein (21), and deletion of the PTAP-L domain in p6 of Gag, or inhibition of the Gag interaction with Tsg101, a protein of the endosomal sorting complex (ESCRT-I) (22), results in accumulation of HIV-1 virions at the plasma membranes.An important role for type I IFN in the innate response to HIV-1 infection is suggested by the observation that deletion of high IFN producing dendritic pDC2 cells results in rapid progression of HIV-1 infection in vivo (23). In vitro, type I IFN inhibits HIV-1 infection both at early steps of replication (24,25) and at the late steps of virus assembly and release (26-28). HIV-1 virions assembled in IFN-treated T cells show a low infectivity, accumulate at the plasma membrane, and have altered morphogenesis (29)(30)(31). Similar defects were seen in IFN-treated cells infected with murine leukemia virus (32). We have shown that IFN-␣-and IFN-␤-mediated inhibition correlates with the induct...

show abstract

Section: Discussionsupporting

confidence: 76%

Innate antiviral response targets HIV-1 release by the induction of ubiquitin-like protein ISG15

Okumura

Pitha-Rowe

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

318

277

View full text Add to dashboard Cite

show abstract

“…This treatment was unable to rescue the cell-surface expression of BST-2 reduced by Vpu (supplemental Fig. S2C), suggesting that the reduced virion production in the presence of the protease inhibitor is not due to a recovery of the cell-surface expression of BST-2 but probably due to, as previously reported, the proteasome-inhibitor-induced reduction of virion release independently of Vpu, resulting from the rapid depletion of the free ubiquitin pool with prolonged drug treatment (52). Because of the unavailability of antibodies against cytoplasmic proteasome markers for immunofluorescence staining, we are unable to perform parallel experiments with treatment of lysosome inhibitors that showed colocalization of Vpu, BST-2, and the lysosome marker cathepsin D. We, therefore, cannot rule out that some fractions of BST-2 might be proteasomally degraded by Vpu.…”

Section: Discussionmentioning

confidence: 52%

HIV-1 Accessory Protein Vpu Internalizes Cell-surface BST-2/Tetherin through Transmembrane Interactions Leading to Lysosomes

Iwabu

Fujita

Kinomoto

et al. 2009

Journal of Biological Chemistry

207

298

View full text Add to dashboard Cite

Bone marrow stromal antigen 2 (BST-2, also known as tetherin) is a recently identified interferon-inducible host restriction factor that can block the production of enveloped viruses by trapping virus particles at the cell surface. This antiviral effect is counteracted by the human immunodeficiency virus type 1 (HIV-1) accessory protein viral protein U (Vpu). Here we show that HIV-1 Vpu physically interacts with BST-2 through their mutual transmembrane domains and leads to the degradation of this host factor via a lysosomal, not proteasomal, pathway. The degradation is partially controlled by a cellular protein, ␤-transducin repeat-containing protein (␤TrCP), which is known to be required for the Vpu-induced degradation of CD4. Importantly, targeting of BST-2 by Vpu occurs at the plasma membrane followed by the active internalization of this host protein by Vpu independently of constitutive endocytosis. Thus, the primary site of action of Vpu is the plasma membrane, where Vpu targets and internalizes cell-surface BST-2 through transmembrane interactions, leading to lysosomal degradation, partially in a ␤TrCP-dependent manner. Also, we propose the following configuration of BST-2 in tethering virions to the cell surface; each of the dimerized BST-2 molecules acts as a bridge between viral and cell membranes. Viral protein U (Vpu)2 is an 81-amino acid type I integral membrane phosphoprotein expressed by human immunodeficiency virus type 1 (HIV-1) (1, 2) and several simian immunodeficiency viruses (3-6). Vpu is not incorporated into virus particles (7), indicating that it acts exclusively in virus-producer cells. Indeed, Vpu is known to play two distinct roles during the later stages of infection. First, Vpu interacts with newly synthesized CD4 molecules complexed with the gp160 envelope glycoprotein precursor in the endoplasmic reticulum (8, 9) and recruits the ␤-transducin repeat-containing protein 1 (␤TrCP-1) subunit of the Skp1-Cullin1-F-box ubiquitin ligase complex (10) as well as ␤TrCP-2 (11) through its phosphoserine residues at positions 52 and 56 in the cytoplasmic (CT) domain (12,13). This event results in proteasome-mediated degradation of CD4 (10, 14, 15) allowing gp160 to resume transport toward the cell surface for virion incorporation. Second, Vpu mediates the enhancement of virion release (16 -18) in a cell type-dependent manner (e.g. HeLa cells require Vpu, whereas COS7 cells do not (19,20)), and its absence leads to the accumulation of viral particles at the cell surface (21).In contrast to the effect of Vpu on CD4 degradation, little had been known about the mechanism by which Vpu enhances the release of virions. The finding that HeLa-COS7 heterokaryons exhibited HeLa-type properties suggested that Vpu-responsive HeLa cells might harbor endogenous a restriction factor(s) that could be counteracted by this viral protein (22), as seen in Vifresponsive cells harboring the antiretroviral factor APOBEC3G counteracted by Vif (23). Neil et al. (24) showed that Vpu-deficient viral particles accumulated ...

show abstract

“…Consequently, a subpopulation of retroviral Gag (ϳ2%) and VP40 is believed to become monoubiquitinated (17,18,47,57,58). This step is crucial in late stages of retroviral budding, since preventing Nedd4 ubiquitin ligases from functioning by using WW dominant-negative fragments (26,46,65) or by using proteasome inhibitors that reduce the amount of free ubiquitin in the cytoplasm (43,47,55) and monoubiquitination (43) inhibits viral budding and release. This defect can be partially corrected in the case of RSV by fusing ubiquitin to Gag polyprotein carrying a functional L-domain motif (47).…”

Section: Discussionmentioning

confidence: 99%

“…E3 ubiquitin ligases of the Nedd4 family were shown to be involved in budding of RSV and MPMV retroviruses (26,48,66). Proteasome inhibitors were found to interfere with the release of HIV-1 (55) and RSV (47), suggesting that depletion of free ubiquitin from the cytoplasm of mammalian cells disrupts retroviral budding and release. The role of ubiquitin in retroviral budding and release remains unclear.…”

mentioning

confidence: 99%

PPPYEPTAP Motif Is the Late Domain of Human T-Cell Leukemia Virus Type 1 Gag and Mediates Its Functional Interaction with Cellular Proteins Nedd4 and Tsg101

Bouamr

Melillo

Wang

et al. 2003

J Virol

121

View full text Add to dashboard Cite

The human T-cell leukemia virus type 1 (HTLV-1) Gag polyprotein contains two adjacent proline-rich motifs (sequence PPPYEPTAP) in the C terminus of the matrix domain. Proline-to-alanine mutations were introduced into either or both motifs of HTLV-1 to determine the effect on the release of HTLV-1 virus-like particles from 293T cells. The release of both single mutants was significantly reduced, whereas a double mutation in both motifs abolished the release of the HTLV-1 particles. Two-hybrid and in vitro binding assays showed that the HTLV-1 Gag polyprotein binds both Tsg101 and Nedd4 proteins. The interaction with HTLV-1 Gag required the central WW domain of Nedd4 and the ubiquitin enzyme variant (UEV) domain of Tsg101. We expressed various fragments of Nedd4 and Tsg101 proteins in 293T cells and tested for their ability to interfere with virion release mediated by the HTLV-1 Gag-Pro polyprotein. Fragments consisting of the N-terminal UEV domain of Tsg101 and the central WW and C-terminal Hect domains of Nedd4 protein all caused transdominant inhibition of HTLV-1 particle release. Similarly, inhibition of the proteasome significantly decreased HTLV-1 particle release. Furthermore, the WW domain overexpression caused an early arrest of HTLV-1 particle morphogenesis before the membrane is deformed into the typical half-shell structure. This result suggests that Nedd4 is involved early in budding of HTLV-1.

show abstract

Proteasome inhibition interferes with Gag polyprotein processing, release, and maturation of HIV-1 and HIV-2

Cited by 308 publications

References 25 publications

Innate antiviral response targets HIV-1 release by the induction of ubiquitin-like protein ISG15

Innate antiviral response targets HIV-1 release by the induction of ubiquitin-like protein ISG15

HIV-1 Accessory Protein Vpu Internalizes Cell-surface BST-2/Tetherin through Transmembrane Interactions Leading to Lysosomes

PPPYEPTAP Motif Is the Late Domain of Human T-Cell Leukemia Virus Type 1 Gag and Mediates Its Functional Interaction with Cellular Proteins Nedd4 and Tsg101

Contact Info

Product

Resources

About