Overlapping Motifs (PTAP and PPEY) within the Ebola Virus VP40 Protein Function Independently as Late Budding Domains: Involvement of Host Proteins TSG101 and VPS-4

Licata, Jillian M.; Simpson-Holley, Martha; Wright, Nathan T.; Han, Ziying; Paragas, Jason; Harty, Ronald N.

doi:10.1128/jvi.77.3.1812-1819.2003

Cited by 265 publications

(335 citation statements)

References 48 publications

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“…3A). Notably, Tsg101 normally associates with detergent-insoluble lipid rafts (Licata et al 2003), and the steady-state levels of Tsg101 are regulated posttranslationally through an unknown mechanism involving the SB (Feng et al 2000). Hence, we raised the possibility that ubiquitylation modifies the localization of a Tsg101-Tal complex, which normally resides in detergent-insoluble structures.…”

Section: Tal Ubiquitylates Tsg101 In Cells and In Vitromentioning

confidence: 99%

Tal, a Tsg101-specific E3 ubiquitin ligase, regulates receptor endocytosis and retrovirus budding

Amit¹,

Yakir²,

Katz³

et al. 2004

Genes Dev.

139

176

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The tumor suppressor gene 101 (tsg101) regulates vesicular trafficking processes in yeast and mammals. We report a novel protein, Tal (Tsg101-associated ligase), whose RING finger is necessary for multiple monoubiquitylation of Tsg101. Bivalent binding of Tsg101 to a tandem tetrapeptide motif (PTAP) and to a central region of Tal is essential for Tal-mediated ubiquitylation of Tsg101. By studying endocytosis of the epidermal growth factor receptor and egress of the human immunodeficiency virus, we conclude that Tal regulates a Tsg101-associated complex responsible for the sorting of cargo into cytoplasm-containing vesicles that bud at the multivesicular body and at the plasma membrane.[Keywords: Endocytosis; growth factor; HIV; ubiquitin; signal transduction] Supplemental material is available at http://www.genesdev.org.

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Section: Tal Ubiquitylates Tsg101 In Cells and In Vitromentioning

confidence: 99%

Tal, a Tsg101-specific E3 ubiquitin ligase, regulates receptor endocytosis and retrovirus budding

Amit¹,

Yakir²,

Katz³

et al. 2004

Genes Dev.

139

176

View full text Add to dashboard Cite

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“…EBOV budding is mediated by two proline-rich motifs -PPxY and PTAP -within VP40 ( Refs 136,137,138,139,140). A full N-terminus of VP40 is required for budding to occur efficiently (Refs 137,139).…”

Section: Budding Inhibitorsmentioning

confidence: 99%

Ebola virus: new insights into disease aetiopathology and possible therapeutic interventions

Geisbert

Hensley

2004

Expert Rev. Mol. Med.

112

106

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Ebola virus (EBOV) gained public notoriety in the last decade largely as a consequence of the highly publicised isolation of a new EBOV species in a suburb of Washington, DC, in 1989, together with the dramatic clinical presentation of EBOV infection and high case-fatality rate in Africa (near 90% in some outbreaks), and the unusual and striking morphology of the virus. Furthermore, there are no vaccines or effective therapies currently available. Progress in understanding the origins of the pathophysiological changes that make EBOV infections of humans so devastating has been slow, primarily because these viruses require special containment for safe research. However, an increasing understanding of the mechanisms of EBOV pathogenesis, facilitated by the development of new tools to elucidate critical regulatory elements in the viral life cycle, is providing new targets that can be exploited for therapeutic interventions. Notably, identifying factors triggering the haemorrhagic complications that characterise EBOV infections led to the development of a strategy to modulate coagulopathy; this therapeutic modality successfully mitigated the effects of EBOV haemorrhagic fever in nonhuman primates. This review summarises our current understanding of EBOV pathogenesis and discusses various approaches to therapeutic intervention based on our current understanding of how EBOV produces a lethal infection.

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“…All mutant NS3 proteins maintain the HA epitope tag in-frame at their C termini. An expression plasmid for Ebola virus (Zaire) VP40 (pVP40-WT) has been described previously (13,14). All plasmids and introduced mutations were confirmed by automated DNA sequencing.…”

Section: Methodsmentioning

confidence: 99%

“…Immunoprecipitation and Western Blotting-Immunoprecipitation was performed as described previously (13,14). Briefly, COS-1 cells were transfected with pNS3-WT or the NS3 mutants indicated above using LipofectAMINE and following the protocol of the supplier (Invitrogen).…”

Section: Methodsmentioning

confidence: 99%

The NS3 Protein of Bluetongue Virus Exhibits Viroporin-like Properties

Han

Harty

2004

Journal of Biological Chemistry

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Bluetongue virus (BTV) 1 is a member of the Orbivirus genus within the Reoviridae family of segmented double-stranded RNA viruses. BTV remains an agriculturally important veterinary pathogen transmitted primarily to sheep by biting midges. BTV encodes seven structural (VP1-7) and four nonstructural (NS1, NS2, NS3, and NS3A) proteins. NS3 is a 229-amino acid protein encoded by the viral S10 RNA segment, and NS3A is a 216-amino acid protein in which synthesis is initiated from an in-frame downstream AUG codon within the Ser-10 RNA segment (1, 2). Both proteins have been shown to be N-linked glycosylated and associated with lipid membranes in infected cells (2-5). Hyatt et al. (3,6,7) were the first to provide evidence that NS3/NS3A may be involved in the late stages of BTV assembly and that NS3/NS3A were required for efficient release of virus-like particles from BTV-infected cells. For example, electron microscopic studies suggested that NS3 was associated with areas of plasma membrane perturbation (3). Similar findings have been reported for the NS3 protein encoded by the closely related African horse sickness virus (5, 8, 9). More recently, an elegant study by Beaton et al. (10) demonstrated that NS3 of BTV facilitates virus release by interacting with specific host-trafficking proteins at the plasma membrane. The authors suggest that NS3 functions as a bridge, linking progeny virions with cellular export machinery to promote virus release (10). Thus, NS3 appears to play a key role in virus assembly and release. We were initially intrigued by the presence of conserved PPXY and PSAP motifs within NS3 that are identical in sequence to late budding domains (L-domains) that we and others have identified in matrix proteins of RNA viruses (11). These L-domains have been shown to interact with specific host proteins, and the resultant virus-host interactions are thought to facilitate virus budding by an, as yet, undetermined mechanism. Results from our initial experiments indicated that the PPXY and PSAP motifs of NS3 did not appear to function as typical L-domains, in that these motifs did not promote the release of NS3-containing virus-like particles from mammalian cells. Interestingly, we did find that cells expressing NS3 were permeable to the translational inhibitor hygromycin B in a dose-dependent manner. This finding suggested that NS3 may be capable of permeabilizing or destabilizing lipid membranes; a property shared by a group of viral proteins termed viroporins (12). We went on to demonstrate that NS3 possesses additional characteristics commonly associated with viroporins. For example, NS3 was able to form homo-oligomers when expressed in mammalian cells. Furthermore, like other viroporins, NS3 is a transmembrane protein containing two transmembrane domains (TM1 and TM2). Mutations introduced into TM1 to disrupt the hydrophobic nature of this region abolished the ability of NS3 to permeabilize the plasma membrane. In contrast, the deletion of amino acids comprising TM2 did not result in disruption of NS3-i...

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Overlapping Motifs (PTAP and PPEY) within the Ebola Virus VP40 Protein Function Independently as Late Budding Domains: Involvement of Host Proteins TSG101 and VPS-4

Cited by 265 publications

References 48 publications

Tal, a Tsg101-specific E3 ubiquitin ligase, regulates receptor endocytosis and retrovirus budding

Tal, a Tsg101-specific E3 ubiquitin ligase, regulates receptor endocytosis and retrovirus budding

Ebola virus: new insights into disease aetiopathology and possible therapeutic interventions

The NS3 Protein of Bluetongue Virus Exhibits Viroporin-like Properties

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