The Nef-Like Effect of Murine Leukemia Virus Glycosylated Gag on HIV-1 Infectivity Is Mediated by Its Cytoplasmic Domain and Depends on the AP-2 Adaptor Complex

Usami, Yoshiko; Попов, Сергей Витальевич; Göttlinger, Heinrich G.

doi:10.1128/jvi.01933-13

Cited by 38 publications

(52 citation statements)

References 91 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…CD4 downregulation by Nef largely relies on enhancing internalization rates from the plasma membrane via an AP-2-and clathrin-dependent pathway that targets CD4 for degradation (47,(53)(54)(55)(56)(57)(58). Similarly, infectivity enhancement of virions produced from SERINC5-expressing cells by Nef requires AP-2 as well as dynamin (31,32,59,60), and it seems plausible that Nef reduces cell surface exposure of SERINC5 by this connection to the host cell endocytic machinery. However, the results obtained with the Nef EDAA mutant reveal that cell surface downregulation may contribute to but is not sufficient for antagonism of SERINC5.…”

Section: Discussionmentioning

confidence: 99%

The Antagonism of HIV-1 Nef to SERINC5 Particle Infectivity Restriction Involves the Counteraction of Virion-Associated Pools of the Restriction Factor

Trautz

Pierini

Wombacher

et al. 2016

J Virol

View full text Add to dashboard Cite

SERINC3 (serine incorporator 3) and SERINC5 are recently identified host cell inhibitors of HIV-1 particle infectivity that are counteracted by the viral pathogenesis factor Nef. Here we confirm that HIV-1 Nef, but not HIV-1 Vpu, antagonizes the particle infectivity restriction of SERINC5. SERINC5 antagonism occurred in parallel with other Nef activities, including cell surface receptor downregulation, trans-Golgi network targeting of Lck, and inhibition of host cell actin dynamics. Interaction motifs with host cell endocytic machinery and the Nef-associated kinase complex, as well as CD4 cytoplasmic tail/HIV-1 protease, were identified as essential Nef determinants for SERINC5 antagonism. Characterization of antagonism-deficient Nef mutants revealed that counteraction of SERINC5 occurs in the absence of retargeting of the restriction factor to intracellular compartments and reduction of SERINC5 cell surface density is insufficient for antagonism. Consistent with virion incorporation of SERINC5 being a prerequisite for its antiviral activity, the infectivity of HIV-1 particles produced in the absence of a SERINC5 antagonist decreased with increasing amounts of virion SERINC5. At low levels of SERINC5 expression, enhancement of virion infectivity by Nef was associated with reduced virion incorporation of SERINC5 and antagonism-defective Nef mutants failed to exclude SERINC5 from virions. However, at elevated levels of SERINC5 expression, Nef maintained infectious HIV particles, despite significant virion incorporation of the restriction factor. These results suggest that in addition to virion exclusion, Nef employs a cryptic mechanism to antagonize virion-associated SERINC5. The involvement of common determinants suggests that the antagonism of Nef to SERINC5 and the downregulation of cell surface CD4 by Nef involve related molecular mechanisms. IMPORTANCEHIV-1 Nef critically determines virus spread and disease progression in infected individuals by incompletely defined mechanisms. SERINC3 and SERINC5 were recently identified as potent inhibitors of HIV particle infectivity whose antiviral activity is antagonized by HIV-1 Nef. To address the mechanism of SERINC5 antagonism, we identified four molecular determinants of Nef antagonism that are all linked to the mechanism by which Nef downregulates cell surface CD4. Functional characterization of these mutants revealed that endosomal targeting and cell surface downregulation of SERINC5 are dispensable and insufficient for antagonism, respectively. In contrast, virion exclusion and antagonism of SERINC5 were correlated; however, Nef was also able to enhance the infectivity of virions that incorporated robust levels of SERINC5. These results suggest that the antagonism of HIV-1 Nef to SERINC5 restriction of virion infectivity is mediated by a dual mechanism that is related to CD4 downregulation. Nef is a myristoylated 25-to 34-kDa protein that, in addition to human immunodeficiency virus type 1 (HIV-1), is encoded by HIV-2 and simian immunodeficiency virus (S...

show abstract

Section: Discussionmentioning

confidence: 99%

The Antagonism of HIV-1 Nef to SERINC5 Particle Infectivity Restriction Involves the Counteraction of Virion-Associated Pools of the Restriction Factor

Trautz

Pierini

Wombacher

et al. 2016

J Virol

View full text Add to dashboard Cite

show abstract

“…Nevertheless, Nef increases the efficiency of reverse transcription in target cells (Aiken and Trono, 1995; Chowers et al, 1995; Schwartz et al, 1995). The effects of Nef on HIV-1 infectivity are determined by variable HIV-1 Env regions (Usami and Göttlinger, 2013) and are dependent on clathrin-mediated endocytosis (Pizzato et al, 2007; Usami et al, 2014). …”

Section: Introductionmentioning

confidence: 99%

A Long Cytoplasmic Loop Governs the Sensitivity of the Anti-viral Host Protein SERINC5 to HIV-1 Nef

Dai

Usami

et al. 2018

Cell Reports

Self Cite

View full text Add to dashboard Cite

SUMMARY We recently identified the multipass transmembrane protein SERINC5 as an antiviral protein that can potently inhibit HIV-1 infectivity and is counteracted by HIV-1 Nef. We now report that the anti-HIV-1 activity, but not the sensitivity to Nef, is conserved among vertebrate SERINC5 proteins. However, a Nef-resistant SERINC5 became Nef sensitive when its intracellular loop 4 (ICL4) was replaced by that of Nef-sensitive human SERINC5. Conversely, human SERINC5 became resistant to Nef when its ICL4 was replaced by that of a Nef-resistant SERINC5. In general, ICL4 regions from SERINCs that exhibited resistance to a given Nef conferred resistance to the same Nef when transferred to a sensitive SERINC, and vice versa. Our results establish that human SERINC5 can be modified to restrict HIV-1 infectivity even in the presence of Nef.

show abstract

“…We also have observed the presence of either an ExxxLL or a YxxL putative Adaptor protein 2 (AP2)-binding motif (Fig. 4D) similar to those found in Nef and glycoGag (13,14). To verify whether ExxxLL is required for S2's effect on infectivity, the two leucine residues were mutated to alanine, and the ability of the resulting mutant protein to counteract SERINC5 was tested.…”

Section: S2 Requires Clathrin-dependent Vesicular Trafficking and A Cmentioning

confidence: 99%

S2 from equine infectious anemia virus is an infectivity factor which counteracts the retroviral inhibitors SERINC5 and SERINC3

Chande

Cuccurullo

Rosa

et al. 2016

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

107

View full text Add to dashboard Cite

The lentivirus equine infectious anemia virus (EIAV) encodes the small protein S2, a pathogenic determinant that is important for virus replication and disease progression in horses. No molecular function had been linked to this accessory protein. We report that S2 can replace the activity of Negative factor (Nef) in HIV-1 infectivity, being required to antagonize the inhibitory activity of Serine incorporator (SERINC) proteins on Nef-defective HIV-1. Like Nef, S2 excludes SERINC5 from virus particles and requires an ExxxLL motif predicted to recruit the clathrin adaptor, Adaptor protein 2 (AP2). Accordingly, functional endocytic machinery is essential for S2-mediated infectivity enhancement, and S2-mediated enhancement is impaired by inhibitors of clathrin-mediated endocytosis. In addition to retargeting SERINC5 to a late endosomal compartment, S2 promotes host factor degradation. Emphasizing the similarity with Nef, we show that S2 is myristoylated, and, as is compatible with a crucial role in posttranslational modification, its N-terminal glycine is required for anti-SERINC5 activity. EIAV-derived vectors devoid of S2 are less susceptible than HIV-1 to the inhibitory effect of both human and equine SERINC5. We then identified the envelope glycoprotein of EIAV as a determinant that also modulates retroviral susceptibility to SERINC5, indicating that EIAV has a bimodal ability to counteract the host factor. S2 shares no sequence homology with other retroviral factors known to counteract SERINC5. Like the primate lentivirus Nef and the gammaretrovirus glycoGag, the accessory protein from EIAV is an example of a retroviral virulence determinant that independently evolved SERINC5-antagonizing activity. SERINC5 therefore plays a critical role in the interaction of the host with diverse retrovirus pathogens.retrovirus | restriction factor | virus infection

show abstract

The Nef-Like Effect of Murine Leukemia Virus Glycosylated Gag on HIV-1 Infectivity Is Mediated by Its Cytoplasmic Domain and Depends on the AP-2 Adaptor Complex

Cited by 38 publications

References 91 publications

The Antagonism of HIV-1 Nef to SERINC5 Particle Infectivity Restriction Involves the Counteraction of Virion-Associated Pools of the Restriction Factor

The Antagonism of HIV-1 Nef to SERINC5 Particle Infectivity Restriction Involves the Counteraction of Virion-Associated Pools of the Restriction Factor

A Long Cytoplasmic Loop Governs the Sensitivity of the Anti-viral Host Protein SERINC5 to HIV-1 Nef

S2 from equine infectious anemia virus is an infectivity factor which counteracts the retroviral inhibitors SERINC5 and SERINC3

Contact Info

Product

Resources

About