The Antiviral Activity of the Cellular Glycoprotein LGALS3BP/90K Is Species Specific

Abstract

Cellular antiviral proteins interfere with distinct steps of replication cycles of viruses. The galectin 3 binding protein (LGALS3BP, also known as 90K) was previously shown to lower the infectivity of nascent human immunodeficiency virus type 1 (HIV-1) virions when expressed in virus-producing cells. This antiviral effect was accompanied by impaired gp160Env processing and reduced viral incorporation of mature Env glycoproteins. Here, we examined the ability of 90K orthologs from primate species to reduce the particle infectivity of distinct lentiviruses. We show that 90K's ability to diminish the infectivity of lentiviral particles is conserved within primate species, with the notable exception of 90K from rhesus macaque. Comparison of active and inactive 90K orthologs and variants uncovered the fact that inhibition of processing of the HIV-1 Env precursor and reduction of cell surface expression of HIV-1 Env gp120 are required, but not sufficient, for 90K-mediated antiviral activity. Rather, 90K-mediated reduction of virion-associated gp120 coincided with antiviral activity, suggesting that 90K impairs the incorporation of HIV-1 Env into budding virions. We show that a single “humanizing” amino acid exchange in the BTB (broad-complex, tramtrack, and bric-à-brac)/POZ (poxvirus and zinc finger) domain is sufficient to fully rescue the antiviral activity of a shortened version of rhesus macaque 90K, but not that of the full-length protein. Comparison of the X-ray structures of the BTB/POZ domains of 90K from rhesus macaques and humans point toward a slightly larger hydrophobic patch at the surface of the rhesus macaque BTB domain that may modulate a direct interaction with either a second 90K domain or a different protein.IMPORTANCE The cellular 90K protein has been shown to diminish the infectivity of nascent HIV-1 particles. When produced in 90K-expressing cells, particles bear smaller amounts of the HIV-1 Env glycoprotein, which is essential for attaching to and entering new target cells in the subsequent infection round. However, whether the antiviral function of 90K is conserved across primates is unknown. Here, we found that 90K orthologs from most primate species, but, surprisingly, not from rhesus macaques, inhibit HIV-1. The introduction of a single amino acid exchange into a short version of the rhesus macaque 90K protein, consisting of the two intermediate domains of 90K, resulted in full restoration of antiviral activity. Structural elucidation of the respective domain suggests that the absence of antiviral activity in the rhesus macaque factor may be linked to a subtle change in protein-protein interaction.

Quantitative Proteomics of Uukuniemi Virus-host Cell Interactions Reveals GBF1 as Proviral Host Factor for Phleboviruses

“…siRNA-transfected or GCA-pretreated Huh-7.5 FLuc or TZM-bl cells were infected with HIV-1, CHIKV, HCV-JcR2a, or HCoV-229E and the infection stopped after up to 48 h. GCA-pretreated TZM-bl cells were infected with HIV-1 strains according to a standard procedure (46). Upon HIV-1 challenge and Tat production, TZM-bl cells indicate infection by expressing luciferase (47,48).…”

Distinct transcriptional modules in the peripheral blood mononuclear cells response to human respiratory syncytial virus or to human rhinovirus in hospitalized infants with bronchiolitis

“…Six out of eight HGS-hubs were previously described as potential therapeutic targets: i) LGALS3BP encodes for galectin 3 binding protein, an antiviral protein that interferes with human immunodeficiency virus type 1 replication diminishing the virions infectivity [32]; ii) EFNB1 codifies an ephrin-B1; members of Efns family are expressed in thymocytes and T cells and they are capable to modulate T cell responses and survival contributing to the integrity of an immune response [33]; iii) APOL1 , codifies for an apolipoprotein 1, which is a mediator protein acting on IFN-activated genes [34, 35] and the proteins of the apolipoprotein family, such as APOL6, has an HRSV antiviral activity related to apoptosis [36]; iv) IDO1 encoded protein was described to control viral infection by modulating specific metabolic events [37]. IDO1 was hyper-expressed after IFN-mediated induction in response to Influenza A viruses and this enzyme is involved in cytokine overproduction and T cell suppression [38]; v) CBL , alias C-CBL , encodes for RING finger E3 ubiquitin ligase and it is involved in antiviral process by activation IFN-I pathway [39]; and vi) PACS2 , that codifies for a sorting protein PACS-2, interacts with a protein Nef of the human immunodeficiency virus type 1 [40].…”

“…Finally, two HGS-hubs could be potential molecular markers for HRSV infection. LGALS3BP , which is also a potential therapeutic target [32], and the other is DCST2 that codifies for a dendritic cell-specific transmembrane protein and its intracellular localization is due in response to toll-like receptor ligation [42]. These genes presented high fold-changes and were hyper-expressed in PBMC from infants infected with HRSV.…”

HIV-1 Envelope Glycoprotein at the Interface of Host Restriction and Virus Evasion

“…It is unknown whether HIV-1 has adopted any mechanisms to counter this factor. The antiviral function of 90K is conserved among primates except the rhesus macaque [47]. Interestingly, 90K impairs gp160 processing and reduces levels of gp120 on the plasma membrane in other species, including the rhesus macaque; however, these functions do not always reduce the infectivity of nascent HIV-1 virions [47].…”