Subcellular Localization and Calcium and pH Requirements for Proteolytic Processing of the Hendra Virus Fusion Protein

Pager, Cara T.; Wurth, Mark; Dutch, Rebecca Ellis

doi:10.1128/jvi.78.17.9154-9163.2004

Cited by 56 publications

(78 citation statements)

References 67 publications

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“…In agreement with our findings, Pager et al (40) recently reported that cleavage of the Hendra virus F protein is also sensitive to increases in intracellular pH levels. Because the Hendra virus F protein also contains a YSRL endocytosis motif in its cytoplasmic tail (6), our results strongly suggest that the closely related Hendra virus F protein is also cleaved by a pH-dependent endosomal protease.…”

Section: Discussionsupporting

confidence: 83%

The Nipah Virus Fusion Protein Is Cleaved within the Endosomal Compartment

Diederich

Moll

Klenk

et al. 2005

Journal of Biological Chemistry

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Nipah virus (NiV) is a recently emerged and highly pathogenic paramyxovirus that causes a systemic infection in animals and humans and can infect a wide range of cultured cells. Interestingly, the NiV fusion (F) protein has a single arginine at the cleavage site similar to paramyxoviruses that are activated by exogenous trypsin-like enzymes only present in specific cells and tissues and therefore only cause localized infections. We show here that NiV F activation is not mediated by an exogenous serum protease but by an endogenous ubiquitous cellular protease after endocytosis of the protein.In addition to endocytosis, acidification of the endosome is a prerequisite for F cleavage. These results show that activation of the NiV F protein depends on a type of proteolytic cleavage that is clearly different from what is known for other paramyxoviral and orthomyxoviral fusion proteins. To our knowledge, this is the first example of a viral class I fusion protein whose activation depends on clathrin-mediated constitutive endocytosis.

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Section: Discussionsupporting

confidence: 83%

The Nipah Virus Fusion Protein Is Cleaved within the Endosomal Compartment

Diederich

Moll

Klenk

et al. 2005

Journal of Biological Chemistry

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“…Specific F protein mutants were subcloned into the pCAGGS expression plasmid as previously described (28). Wt HeV F and G (also provided by Lin-Fa Wang) genes were ligated into pCAGGS as described previously (29).…”

Section: Plasmidsmentioning

confidence: 99%

A Conserved Region between the Heptad Repeats of Paramyxovirus Fusion Proteins Is Critical for Proper F Protein Folding

2007

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Paramyxoviruses are a diverse family which utilizes a fusion (F) protein to enter cells via fusion of the viral lipid bilayer with a target cell membrane. Although certain regions of F are known to play critical roles in membrane fusion, the function of much of the protein remains unclear. Sequence alignment of a set of paramyxovirus F proteins and analysis utilizing Block Maker identified a region of conserved amino acid sequence in a large domain between the heptad repeats of F 1 , designated CBF 1 . We employed site-directed mutagenesis to analyze the function of completely conserved residues of CBF 1 in both the simian virus 5 (SV5) and Hendra virus F proteins. The majority of CBF 1 point mutants were deficient in homotrimer formation, proteolytic processing, and transport to the cell surface. For some SV5 F mutants, proteolytic cleavage and surface expression could be restored by expression at 30°C, and varying levels of fusion promotion were observed at this temperature. In addition, the mutant SV5 F V402A displayed a hyperfusogenic phenotype at both 30°C and 37°C, indicating this mutation allows for efficient fusion with only an extremely small amount of cleaved, active protein. The recently published prefusogenic structure of PIV5/SV5 F [Yin, H.S., et al. (2006) Nature 439, 38-44] indicates that residues within and flanking CBF 1 interact with the fusion peptide domain. Together, these data suggest that CBF 1 -fusion peptide interactions are critical for the initial folding of paramyxovirus F proteins from across this important viral family, and can also modulate subsequent membrane fusion promotion.The family Paramyxoviridae comprises many diverse members, including well-known human pathogens such as measles, mumps and respiratory syncytial virus (RSV), as well as animal pathogens like parainfluenza virus 5 (PIV5/SV5), and the newly emerged, zoonotic Hendra and Nipah viruses. Hendra virus first emerged in 1994 and caused an outbreak of severe respiratory illness near Brisbane, Australia. This resulted in the deaths of fourteen horses and two out of three humans infected, succumbing either to respiratory illness or to viral meningoencephalitis (1,2). Nipah virus was responsible for an outbreak of viral encephalitis in Malaysia in 1998, which resulted in the deaths of 105 people and the preventative destruction of over one million swine (3). Hendra and Nipah virus are classified as NIAID priority pathogens and DHHS Select Agents, and no antiviral therapies currently exist for these fatal viruses. Hendra and Nipah are grouped into the Henipavirus genus within the family, due in part to the fact that while they possess 88% homology to each other, they share less than 30% homology with the rest of the family (4,5). † This work was supported by a grant from the National Institute of Allergy and Infectious Diseases (AI-51517) to R.E.D. A.E.G. was supported in part by a predoctoral fellowship from the American Heart Association, Ohio Valley Affiliate (0415223B).* To whom correspondence should be addres...

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“…1), including heptad repeats (HR) critical for promotion of membrane fusion (reviewed in reference 5) and posttranslational cleavage of the precursor form (F 0 ) to the fusogenic heterodimer, F 1 ϩF 2 (13). The Hendra virus F ectodomain contains five N-X-S/T motifs for the potential addition of N-linked carbohydrates, two in F 1 and three in F 2 .…”

mentioning

confidence: 99%

“…While N485 was previously identified as a potential site for N-linked glycosylation (9), a proline at position 486 should preclude N-linked glycosylation. To analyze expression and mobility, the wildtype (wt) or mutant Hendra virus F genes in the pCAGGS expression plasmid (12) were transfected into Vero cells and metabolic labeling and immunoprecipitation were performed as previously described (13). Samples were separated on a 10% polyacrylamide gel.…”

mentioning

confidence: 99%

Role of N-Linked Glycosylation of the Hendra Virus Fusion Protein

Carter

Pager

Fowler

et al. 2005

J Virol

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The Hendra virus fusion (F) protein contains five potential sites for N-linked glycosylation in the ectodomain. Examination of F protein mutants with single asparagine-to-alanine mutations indicated that two sites in the F 2 subunit (N67 and N99) and two sites in the F 1 subunit (N414 and N464) normally undergo N-linked glycosylation. While N-linked modification at N414 is critical for protein folding and transport, F proteins lacking carbohydrates at N67, N99, or N464 remained fusogenically active. As N464 lies within heptad repeat B, these results contrast with those seen for several paramyxovirus F proteins.

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Subcellular Localization and Calcium and pH Requirements for Proteolytic Processing of the Hendra Virus Fusion Protein

Cited by 56 publications

References 67 publications

The Nipah Virus Fusion Protein Is Cleaved within the Endosomal Compartment

The Nipah Virus Fusion Protein Is Cleaved within the Endosomal Compartment

A Conserved Region between the Heptad Repeats of Paramyxovirus Fusion Proteins Is Critical for Proper F Protein Folding

Role of N-Linked Glycosylation of the Hendra Virus Fusion Protein

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