Tegument Proteins of Human Cytomegalovirus

Kalejta, Robert F.

doi:10.1128/mmbr.00040-07

Cited by 163 publications

(163 citation statements)

References 213 publications

(276 reference statements)

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“…Deenvelopment is a key step in the viral replication process because it allows the DNA-containing capsid to separate from the viral envelope, a necessary step for the translocation event. The deenvelopment of HCMV is cell type-dependent; it occurs rapidly in fibroblasts during direct fusion at the plasma membrane or after macropinocytosis, and also after intracellular fusion with endosomes in epithelial and endothelial cells (27,(36)(37)(38). To our knowledge, this is the first report of the deenvelopment of HCMV in recycling endosomes.…”

Section: Discussionmentioning

confidence: 79%

Viral binding-induced signaling drives a unique and extended intracellular trafficking pattern during infection of primary monocytes

Kim

Collins-McMillen

Caposio

et al. 2016

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

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We initiated experiments to examine the infection of monocytes postentry. New data show that human cytomegalovirus (HCMV) DNA is detected in the nucleus beginning only at 3 d postinfection in monocytes, compared with 30 min postinfection in fibroblasts and endothelial cells, suggesting that HCMV nuclear translocation in monocytes is distinct from that seen in other cell types. We now show that HCMV is initially retained in early endosomes and then moves sequentially to the trans-Golgi network (TGN) and recycling endosomes before nuclear translocation. HCMV is retained initially as a mature particle before deenvelopment in recycling endosomes. Disruption of the TGN significantly reduced nuclear translocation of viral DNA, and HCMV nuclear translocation in infected monocytes was observed only when correct gH/gL/UL128-131/integrin/c-Src signaling occurred. Taken together, our findings show that viral binding of the gH/gL/UL128-131 complex to integrins and the ensuing c-Src signaling drive a unique nuclear translocation pattern that promotes productive infection and avoids viral degradation, suggesting that it represents an additional viral evasion/survival strategy.monocytes | viral trafficking | gH/gL/UL128-131 complex | integrins | nuclear translocation pathway H uman cytomegalovirus (HCMV) infection usually results in an asymptomatic lifelong persistent infection in healthy individuals after primary infection (1, 2). Although HCMV infection rarely causes disease in immunocompetent individuals, it can cause severe/ fatal disease in immunocompromised patients, such as congenitally infected neonates, patients with AIDS, and transplant recipients (3-6). HCMV infection is also associated with the development of cardiovascular diseases, including atherosclerosis, restenosis, and transplant vascular sclerosis, as well as some cancers (7-10). This wide range of pathological complications results from viral spread to multiple organs and the broad cellular tropism displayed by HCMV following infection (11).Monocytes are a primary site of persistent HCMV infection, and HCMV-infected monocytes are believed to play a key role in the hematogenous dissemination of the virus to target organs following primary infection (12). For HCMV to infect primary monocytes, it must overcome several biological barriers to successfully mediate viral spread and persistence. For example, monocytes do not initially support de novo HCMV gene expression and viral replication (13), and they have a lifespan of only 1-3 d in circulation under normal homeostatic conditions (14, 15). Understanding how HCMV overcomes these biological barriers following infection may provide clues to the underlying causes of HCMV pathogenesis and persistence. Our laboratory has provided molecular evidence for how HCMV evolved to deal with these biological barriers (16)(17)(18)(19)(20)(21)(22).We have shown that the biological changes in HCMV-infected monocytes are triggered by the binding of gB to EGFR (19) and binding of the gH/gL/UL128-131 complex to β1 and β3 integri...

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Section: Discussionmentioning

confidence: 79%

Viral binding-induced signaling drives a unique and extended intracellular trafficking pattern during infection of primary monocytes

Kim

Collins-McMillen

Caposio

et al. 2016

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

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“…A mixture (1:1) of both samples was labeled with 3-[(4-carboxymethyl)phenylmethyl]-39-ethyloxacarbocyanine halide N-hydroxysuccinimidyl ester and functions as an internal control that allows adequate comparison between gels. The labeling reactions were stopped by adding 0.2 mM lysine, diluted with rehydration buffer (8 M urea, 2 M thiourea, 4% CHAPS, 150 mM DTT, 1% biolyte [pH [3][4][5][6][7][8][9][10], and 0.002% bromophenol blue), and combined according to the experimental design. Samples (150 mg) were rehydrated passively into immobilized pH gradient strips (24 cm; pH 3-10, nonlinear) for 15 h at room temperature prior to isoelectric focusing in the IPGphor system (GE Healthcare) for 64 kVh.…”

Section: Fluorescent Two-dimensional Difference Gel Electrophoresismentioning

confidence: 99%

“…The region between capsid and lipid envelope is called the tegument and contains .30 virally encoded proteins. These tegument proteins are delivered into the host cell cytoplasm upon fusion of the HCMV virion with the cell membrane (7,8) and contribute essentially to immune evasion and viral replication (9-13).…”

mentioning

confidence: 99%

Noncytotoxic Inhibition of Cytomegalovirus Replication through NK Cell Protease Granzyme M-Mediated Cleavage of Viral Phosphoprotein 71

Domselaar¹,

Philippen²,

Quadir³

et al. 2010

The Journal of Immunology

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Granzyme M (GrM) is highly expressed in cytotoxic granules of NK cells, which provide the first line of defense against viral pathogens. GrM knockout mice show increased susceptibility toward murine CMV infection. Although GrM is a potent inducer of cell death, the mechanism by which GrM eliminates viruses remains elusive. In this paper, we show that purified human GrM in combination with the perforin-analog streptolysin O (SLO) strongly inhibited human CMV (HCMV) replication in fibroblasts in the absence of host cell death. In a proteomic approach, GrM was highly specific toward the HCMV proteome and most efficiently cleaved phosphoprotein 71 (pp71), an HCMV tegument protein that is critical for viral replication. Cleavage of pp71 occurred when viral lysates were incubated with purified GrM, when intact cells expressing recombinant pp71 were challenged with living cytotoxic effector cells, and when HCMV-infected fibroblasts were incubated with SLO and purified GrM. GrM directly cleaved pp71 after Leu439, which coincided with aberrant cellular localization of both pp71 cleavage fragments as determined by confocal immunofluorescence. In a luciferase reporter assay, cleavage of pp71 after Leu439 by GrM completely abolished the ability of pp71 to transactivate the HCMV major immediate-early promoter, which is indispensable for effective HCMV replication. Finally, GrM decreased immediate-early 1 protein expression in HCMV-infected fibroblasts. These results indicate that the NK cell protease GrM mediates cell death-independent antiviral activity by direct cleavage of a viral substrate.

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“…Current data does not fully explain the timing of addition, specific order, and complex network of protein-protein interactions that make up the tegument layer, but this is an active and exciting area of exploration. Several studies have investigated the role of specific tegument proteins, within a specific herpesvirus (including my own manuscript and this thesis) (reviewed in (119,143,149,160,(211)(212)(213)), and while critical to advancing our understanding of this complex and multifaceted layer of the virion, none convey a complete picture or fully elucidate the details of this process. Research on CMV shows that many glycoproteins and tegument proteins aggregate to a perinuclear assembly-like structure, that could be the site of assembly and egress (64,65,273), but it is not present during lytic infection with all herpesviruses.…”

Section: Herpesvirus Replicationmentioning

confidence: 99%

“…Studies examining the components of the herpesvirus virions indicate that tegument proteins make up over half of the total number of viral proteins (reviewed in (149) involving at least a subset of the tegument proteins. This ordering is significant enough to be further divided into "inner" and "outer" tegument layers, which are seen with cryo-electron tomography ( Figure 1-4) (62).…”

Section: The Herpesvirus Tegumentmentioning

confidence: 99%

Role of RRV ORF52 in Virion Maturation

Anderson¹

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Rhesus monkey rhadinovirus (RRV) is a close relative of the human pathogen, Kaposi's Sarcoma-Associated Herpesvirus (KSHV). Primary infection with KSHV in culture is highly inefficient and it predominantly adopts a latent phenotype, expressing only a minimal number of viral genes and producing no progeny virions. This contrasts with RRV in culture, which replicates to high viral titer and produces abundant progeny virions, making it a useful model to study gammaherpesvirus lytic replication, virion structure, and the potential roles of tegument proteins in the biology of gammaherpesviruses. Initial work in our laboratory determined that the RRV virion was composed of 33 virally encoded proteins. Of these, 17 are tegument proteins, five of which are unique to the gammaherpesvirus subfamily. ORF52 is one of these five gammaherpesvirus specific tegument proteins and is the focus of this dissertation. This protein is highly abundant within the virion (approximately 1000 copies per particle) and it is closely associated with the capsid. Our results describe a critical role for ORF52 in the cytoplasmic-based later stages of virion morphogenesis. Without ORF52, capsids fail to undergo tegumentation, which is necessary for final envelopment and production of fully infectious virions. In a later section of this dissertation, we also describe preliminary data proposing that ORF52 may play a direct or indirect role in virion transport through interaction with cellular microtubules.iii ACKNOWLEDGEMENTS I grew up in a small, blue-collar, southern Illinois town where most people stay local and focus on getting by day-to-day, not on things like big cities and advanced degrees. I didn't even know what "graduate school" was until several years into my undergraduate education in Chicago, which, by the way, took me 9 years to complete because I worked full-time and went to school off-and-on and part-time when time and money permitted. The reason I share this is because I didn't get here alone, I didn't even know where "here" was and if I'm honest, I don't think I ever really believed I would earn a PhD, because where I'm from, things like that just don't happen to people like me. There truly are so many people I am honored to thank for helping, and supporting, me at various points in this long, wonderful, horrible, amazing, and trying journey that has been the last 10 years of my life, 7 of those at UVa.

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Tegument Proteins of Human Cytomegalovirus

Cited by 163 publications

References 213 publications

Viral binding-induced signaling drives a unique and extended intracellular trafficking pattern during infection of primary monocytes

Viral binding-induced signaling drives a unique and extended intracellular trafficking pattern during infection of primary monocytes

Noncytotoxic Inhibition of Cytomegalovirus Replication through NK Cell Protease Granzyme M-Mediated Cleavage of Viral Phosphoprotein 71

Role of RRV ORF52 in Virion Maturation

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