Biochemical and Genetic Definition of the Cellular Protease Required for HIV-1 gp160 Processing

Franzusoff, Alex; Volpe, Alison M.; Josse, Denise; Pîchuantes, Sergio; Wolf, Joseph R.

doi:10.1074/jbc.270.7.3154

Cited by 29 publications

(32 citation statements)

References 41 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…During transport through the secretory pathway, or possibly within an endosomal compartment (Franzusoff et al, 1995), the extracellular (luminal) domain of gp160 is proteolytically cleaved by furin or a furin-like protease to generate the surface unit (SU, gp120) and transmembrane (TM, gp41) proteins of the mature Env glycoprotein. The first ϳ650 amino acids (depending on the strain of virus) of gp160 form gp120 and the ectodomain of gp41, followed by a short transmembrane domain.…”

Section: Introductionmentioning

confidence: 99%

A Conserved Dileucine Motif Mediates Clathrin and AP-2–dependent Endocytosis of the HIV-1 Envelope Protein

Byland

Vance

Hoxie

et al. 2007

MBoC

123

133

View full text Add to dashboard Cite

During the assembly of enveloped viruses viral and cellular components essential for infectious particles must colocalize at specific membrane locations. For the human and simian immunodeficiency viruses (HIV and SIV), sorting of the viral envelope proteins (Env) to assembly sites is directed by trafficking signals located in the cytoplasmic domain of the transmembrane protein gp41 (TM). A membrane proximal conserved GYxxØ motif mediates endocytosis through interaction with the clathrin adaptor AP-2. However, experiments with SIV mac239 Env indicate the presence of additional signals. Here we show that a conserved C-terminal dileucine in HIV HxB2 also mediates endocytosis. Biochemical and morphological assays demonstrate that the C-terminal dileucine motif mediates internalization as efficiently as the GYxxØ motif and that both must be removed to prevent Env internalization. RNAi experiments show that depletion of the clathrin adaptor AP-2 leads to increased plasma membrane expression of HIV Env and that this adaptor is required for efficient internalization mediated by both signals. The redundancy of conserved endocytosis signals and the role of the SIV mac239 Env GYxxØ motif in SIV pathogenesis, suggest that these motifs have functions in addition to endocytosis, possibly related to Env delivery to the site of viral assembly and/or incorporation into budding virions. INTRODUCTIONThe assembly of enveloped animal viruses requires that the viral and cellular components needed to make infectious particles are brought to the same site within the infected cell at the same time. For the primate lentiviruses (the human immunodeficiency viruses types 1 and 2 [HIV-1 and -2] and the simian immunodeficiency viruses [SIV]) the key viral structural proteins required to generate infectious particles are Gag, Gag-Pol, and Env. Although Gag alone can promote the formation of virus-like particles, Env and Gag-Pol are both essential for the formation of infectious virions. Although a considerable amount is known about these proteins, little is understood of the mechanisms through which they are targeted to the sites of assembly in infected cells.In many cell types, HIV assembles at the plasma membrane and, in the course of Gag assembly, the particles derive their membrane from the plasma membrane. For these particles to be infectious, Env must be transported to the cell surface, but the level to which it is incorporated into budding virions is unclear. Recent data have suggested that fewer than 10 Env protein complexes (trimers) are incorporated per virion (Chertova et al., 2002;Zhu et al., 2003), and early studies of HIV infected T-cells showed that much of the newly synthesized Env is transported to lysosomes and degraded (Willey et al., 1988). However, it has recently become evident that in macrophages the assembly of Envcontaining infectious HIV occurs on intracellular membranes, that have some characteristics in common with late endosomes (Raposo et al., 2002;Pelchen-Matthews et al., 2003). The assembly of virus in distinct...

show abstract

Section: Introductionmentioning

confidence: 99%

A Conserved Dileucine Motif Mediates Clathrin and AP-2–dependent Endocytosis of the HIV-1 Envelope Protein

Byland

Vance

Hoxie

et al. 2007

MBoC

123

133

View full text Add to dashboard Cite

show abstract

“…We have shown that heterologous expression of HIV-1 gpl60 in yeast resulted in the proper targeting and processing of the protein in the secretory pathway (33). Using genetic and biochemical approaches, the yeast Kex2 protease was shown to be both necessary and sufficient for correctly processing gp160 (33,34).…”

mentioning

confidence: 99%

Isolation of the human PC6 gene encoding the putative host protease for HIV-1 gp160 processing in CD4+ T lymphocytes.

Miranda

Wolf

Pîchuantes

et al. 1996

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

View full text Add to dashboard Cite

Production of infectious HIV-1 virions is dependent on the processing ofenvelope glycoprotein gpl60 by a host cell protease. The protease in human CD4+ T lymphocytes has not been unequivocally identified, yet members ofthe family of mammalian. subtilisin-like protein convertases (SPCs), which are soluble or membrane-bound proteases of the secretory pathway, best fulfill the criteria. These proteases are required for proprotein maturation and cleave at paired basic amino acid motifs in numerous cellular and viral glycoprotein precursors, both in vivo and in vitro. To identify the gpl60 processing protease, we have used reverse tran-

show abstract

“…The Env spike is a trimer of heterodimers composed of gp41 and gp120 subunits, which are generated when a protease, usually furin, cleaves the proprotein gp160 glycoprotein (26)(27)(28)(29)(30)(31). Furin most probably cleaves gp160 in the trans-Golgi network (TGN), but it is able to cycle between the TGN, the endosomal compartments, and the cell surface and is also believed to be able to act in the early secretory pathway (27,32,33).…”

mentioning

confidence: 99%

Molecular Architecture of the Cleavage-Dependent Mannose Patch on a Soluble HIV-1 Envelope Glycoprotein Trimer

Behrens

Harvey

Milne

et al. 2017

J Virol

135

View full text Add to dashboard Cite

The formation of a correctly folded and natively glycosylated HIV-1 viral spike is dependent on protease cleavage of the gp160 precursor protein in the Golgi apparatus. Cleavage induces a compact structure which not only renders the spike capable of fusion but also limits further maturation of its extensive glycosylation. The redirection of the glycosylation pathway to preserve underprocessed oligomannose-type glycans is an important feature in immunogen design, as glycans contribute to or influence the epitopes of numerous broadly neutralizing antibodies.Here we present a quantitative site-specific analysis of a recombinant, trimeric mimic of the native HIV-1 viral spike (BG505 SOSIP.664) compared to the corresponding uncleaved pseudotrimer and the matched gp120 monomer. We present a detailed molecular map of a trimer-associated glycan remodeling that forms a localized subdomain of the native mannose patch. The formation of native trimers is a critical design feature in shaping the glycan epitopes presented on recombinant vaccine candidates. IMPORTANCEThe envelope spike of human immunodeficiency virus type 1 (HIV-1) is a target for antibody-based neutralization. For some patients infected with HIV-1, highly potent antibodies have been isolated that can neutralize a wide range of circulating viruses. It is a goal of HIV-1 vaccine research to elicit these antibodies by immunization with recombinant mimics of the viral spike. These antibodies have evolved to recognize the dense array of glycans that coat the surface of the viral molecule. We show how the structure of these glycans is shaped by steric constraints imposed upon them by the native folding of the viral spike. This information is important in guiding the development of vaccine candidates.KEYWORDS furin, glycan, glycosylation, human immunodeficiency virus, neutralizing antibodies, oligosaccharides, structure, vaccines T he trimeric envelope (Env) glycoprotein spike of human immunodeficiency virus type 1 (HIV-1) plays a crucial role in mediating host cell infection. Its exposed position on the virus surface also makes it the target for potent, broadly neutralizing antibodies (bNAbs) that are produced in a subset of infected individuals and that now influence the design of Env immunogens intended to induce similar antibody specificities. Env is extensively glycosylated, with glycans contributing to a significant proportion of the glycoprotein's mass (1). The heavily glycosylated surface of Env has been referred to as the "silent face," with the glycans acting to shield the underlying viral protein surface from immune surveillance (2-4). The glycan shield constantly evolves to protect the virus from newly produced neutralizing antibodies. However, compared to the highly diverse protein component of Env, many of the potential

show abstract

Biochemical and Genetic Definition of the Cellular Protease Required for HIV-1 gp160 Processing

Cited by 29 publications

References 41 publications

A Conserved Dileucine Motif Mediates Clathrin and AP-2–dependent Endocytosis of the HIV-1 Envelope Protein

A Conserved Dileucine Motif Mediates Clathrin and AP-2–dependent Endocytosis of the HIV-1 Envelope Protein

Isolation of the human PC6 gene encoding the putative host protease for HIV-1 gp160 processing in CD4+ T lymphocytes.

Molecular Architecture of the Cleavage-Dependent Mannose Patch on a Soluble HIV-1 Envelope Glycoprotein Trimer

Contact Info

Product

Resources

About