scholarly journals MARCH8 inhibits viral infection by two different mechanisms

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Yanzhao Zhang ◽  
Takuya Tada ◽  
Seiya Ozono ◽  
Satoshi Kishigami ◽  
Hideaki Fujita ◽  
...  
Keyword(s):  
Viral Infection ◽  
Molecular Mechanisms ◽  
Inhibitory Effect ◽  
Envelope Glycoproteins ◽  
Intracellular Protein ◽  
Virion Incorporation ◽  
Lysine Residues ◽  
Vesicular Stomatitis ◽  
Dependent Pathway ◽  
Hiv 1

Membrane-associated RING-CH 8 (MARCH8) inhibits infection with both HIV-1 and vesicular stomatitis virus G-glycoprotein (VSV-G)-pseudotyped viruses by reducing virion incorporation of envelope glycoproteins. The molecular mechanisms by which MARCH8 targets envelope glycoproteins remain unknown. Here, we show two different mechanisms by which MARCH8 inhibits viral infection. Viruses pseudotyped with the VSV-G mutant, in which cytoplasmic lysine residues were mutated, were insensitive to the inhibitory effect of MARCH8, whereas those with a similar lysine mutant of HIV-1 Env remained sensitive to it. Indeed, the wild-type VSV-G, but not its lysine mutant, was ubiquitinated by MARCH8. Furthermore, the MARCH8 mutant, which had a disrupted cytoplasmic tyrosine motif that is critical for intracellular protein sorting, did not inhibit HIV-1 Env-mediated infection, while it still impaired infection by VSV-G-pseudotyped viruses. Overall, we conclude that MARCH8 reduces viral infectivity by downregulating envelope glycoproteins through two different mechanisms mediated by a ubiquitination-dependent or tyrosine motif-dependent pathway.

scholarly journals MARCH8 inhibits viral infection by two different mechanisms

2020 ◽  
Author(s):  
Yanzhao Zhang ◽  
Takuya Tada ◽  
Seiya Ozono ◽  
Satoshi Kishigami ◽  
Hideaki Fujita ◽  
...  
Keyword(s):  
Viral Infection ◽  
Molecular Mechanisms ◽  
Inhibitory Effect ◽  
Envelope Glycoproteins ◽  
Intracellular Protein ◽  
Virion Incorporation ◽  
Lysine Residues ◽  
Vesicular Stomatitis ◽  
Dependent Pathway ◽  
Hiv 1

ABSTRACTMembrane-associated RING-CH 8 (MARCH8) inhibits infection with both HIV-1 and vesicular stomatitis virus G-glycoprotein (VSV-G)-pseudotyped viruses by reducing virion incorporation of envelope glycoproteins. The molecular mechanisms by which MARCH8 targets envelope glycoproteins remain unknown. Here, we show two different mechanisms by which MARCH8 inhibits viral infection. Viruses pseudotyped with the VSV-G mutant, in which cytoplasmic lysine residues were mutated, were insensitive to the inhibitory effect of MARCH8, whereas those with a similar lysine mutant of HIV-1 Env remained sensitive to it. Indeed, the wild-type VSV-G, but not its lysine mutant, was ubiquitinated by MARCH8. Furthermore, the MARCH8 mutant, which had a disrupted cytoplasmic tyrosine motif that is critical for intracellular protein sorting, did not inhibit HIV-1 Env-mediated infection, while it still impaired infection by VSV-G-pseudotyped viruses. Overall, we conclude that MARCH8 reduces viral infectivity by downregulating envelope glycoproteins through two different mechanisms mediated by a ubiquitination-dependent or tyrosine motif-dependent pathway.

scholarly journals Mechanism of Viral Glycoprotein Targeting by Membrane-Associated RING-CH Proteins

mBio ◽  
2021 ◽  
Vol 12 (2) ◽  
Author(s):  
Cheng Man Lun ◽  
Abdul A. Waheed ◽  
Ahlam Majadly ◽  
Nicole Powell ◽  
Eric O. Freed
Keyword(s):  
Antiviral Activity ◽  
Envelope Glycoproteins ◽  
Type I ◽  
Viral Glycoprotein ◽  
Enveloped Viruses ◽  
S Protein ◽  
Virion Incorporation ◽  
Endogenous Expression ◽  
Viral Glycoproteins ◽  
Hiv 1

ABSTRACT An emerging class of cellular inhibitory proteins has been identified that targets viral glycoproteins. These include the membrane-associated RING-CH (MARCH) family of E3 ubiquitin ligases that, among other functions, downregulate cell surface proteins involved in adaptive immunity. The RING-CH domain of MARCH proteins is thought to function by catalyzing the ubiquitination of the cytoplasmic tails (CTs) of target proteins, leading to their degradation. MARCH proteins have recently been reported to target retroviral envelope glycoproteins (Env) and vesicular stomatitis virus G glycoprotein (VSV-G). However, the mechanism of antiviral activity remains poorly defined. Here we show that MARCH8 antagonizes the full-length forms of HIV-1 Env, VSV-G, Ebola virus glycoprotein (EboV-GP), and the spike (S) protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), thereby impairing the infectivity of virions pseudotyped with these viral glycoproteins. This MARCH8-mediated targeting of viral glycoproteins requires the E3 ubiquitin ligase activity of the RING-CH domain. We observe that MARCH8 protein antagonism of VSV-G is CT dependent. In contrast, MARCH8-mediated targeting of HIV-1 Env, EboV-GP, and SARS-CoV-2 S protein by MARCH8 does not require the CT, suggesting a novel mechanism of MARCH-mediated antagonism of these viral glycoproteins. Confocal microscopy data demonstrate that MARCH8 traps the viral glycoproteins in an intracellular compartment. We observe that the endogenous expression of MARCH8 in several relevant human cell types is rapidly inducible by type I interferon. These results help to inform the mechanism by which MARCH proteins exert their antiviral activity and provide insights into the role of cellular inhibitory factors in antagonizing the biogenesis, trafficking, and virion incorporation of viral glycoproteins. IMPORTANCE Viral envelope glycoproteins are an important structural component on the surfaces of enveloped viruses that direct virus binding and entry and also serve as targets for the host adaptive immune response. In this study, we investigate the mechanism of action of the MARCH family of cellular proteins that disrupt the trafficking and virion incorporation of viral glycoproteins across several virus families. This research provides novel insights into how host cell factors antagonize viral replication, perhaps opening new avenues for therapeutic intervention in the replication of a diverse group of highly pathogenic enveloped viruses.

scholarly journals Enhanced Fusion and Virion Incorporation for HIV-1 Subtype C Envelope Glycoproteins with Compact V1/V2 Domains

2013 ◽  
Vol 88 (4) ◽  
pp. 2083-2094 ◽  
Author(s):  
M. Cavrois ◽  
J. Neidleman ◽  
M. L. Santiago ◽  
C. A. Derdeyn ◽  
E. Hunter ◽  
...  
Keyword(s):  
Envelope Glycoproteins ◽  
Subtype C ◽  
Virion Incorporation ◽  
Hiv 1

scholarly journals MARCH8 targets cytoplasmic lysine residues of various viral envelope glycoproteins

2021 ◽  
Author(s):  
Yanzhao Zhang ◽  
Seiya Ozono ◽  
Takuya Tada ◽  
Minoru Tobiume ◽  
Masanori Kameoka ◽  
...  
Keyword(s):  
Rabies Virus ◽  
Chikungunya Virus ◽  
Transmembrane Protein ◽  
Ring Finger ◽  
Lymphocytic Choriomeningitis ◽  
Viral Envelope ◽  
Envelope Glycoproteins ◽  
Lysine Residues ◽  
Viral Envelopes ◽  
Hiv 1

The host transmembrane protein MARCH8 is a RING finger E3 ubiquitin ligase that downregulates various host transmembrane proteins, such as MHC-II. We have recently reported that MARCH8 expression in virus-producing cells impairs viral infectivity by reducing virion incorporation of not only HIV-1 envelope glycoproteins but also vesicular stomatitis virus G-glycoprotein through two different pathways. However, the MARCH8 inhibition spectrum remains largely unknown. Here, we investigate the antiviral spectrum of MARCH8 using HIV-1 pseudotyped with a variety of viral envelope glycoproteins. Pseudotyping experiments revealed that viral envelopes derived from the rhabdovirus, arenavirus, coronavirus, and togavirus (alphavirus) families were sensitive to MARCH8-mediated inhibition. Lysine mutations at the cytoplasmic tails of rabies virus-G, lymphocytic choriomeningitis virus glycoproteins, SARS-CoV and SARS-CoV-2 spike proteins, and Chikungunya virus and Ross River virus E2 proteins conferred resistance to MARCH8. Immunofluorescence showed impaired downregulation of the mutants of these viral envelopes by MARCH8, followed by lysosomal degradation, suggesting that MARCH8-mediated ubiquitination leads to intracellular degradation of these envelopes. Indeed, rabies virus-G and Chikungunya virus E2 proteins proved to be clearly ubiquitinated. We conclude that MARCH8 has inhibitory activity on a variety of viral envelope glycoproteins whose cytoplasmic lysine residues are targeted by this antiviral factor.

scholarly journals Adenosine Suppresses Cholangiocarcinoma Cell Growth and Invasion in Equilibrative Nucleoside Transporters-Dependent Pathway

2020 ◽  
Vol 21 (3) ◽  
pp. 814 ◽  
Author(s):  
Kornkamon Lertsuwan ◽  
Supathra Phoaubon ◽  
Nathapol Tasnawijitwong ◽  
Jomnarong Lertsuwan
Keyword(s):  
Cell Growth ◽  
Molecular Mechanisms ◽  
Inhibitory Effect ◽  
Adenosine Kinase ◽  
Nucleoside Transporters ◽  
Cancer Cell Growth ◽  
Equilibrative Nucleoside Transporters ◽  
Cholangiocarcinoma Cell ◽  
Amp Activated Protein Kinase ◽  
Dependent Pathway

Cholangiocarcinoma (CCA) is a lethal disease with increasing incidence worldwide. Previous study showed that CCA was sensitive to adenosine. Thereby, molecular mechanisms of CCA inhibition by adenosine were examined in this study. Our results showed that adenosine inhibited CCA cells via an uptake of adenosine through equilibrative nucleoside transporters (ENTs), instead of activation of adenosine receptors. The inhibition of ENTs by NBTI caused the inhibitory effect of adenosine to subside, while adenosine receptor antagonists, caffeine and CGS-15943, failed to do so. Intracellular adenosine level was increased after adenosine treatment. Also, a conversion of adenosine to AMP by adenosine kinase is required in this inhibition. On the other hand, inosine, which is a metabolic product of adenosine has very little inhibitory effect on CCA cells. This indicates that a conversion of adenosine to inosine may reduce adenosine inhibitory effect. Furthermore, there was no specific correlation between level of proinflammatory proteins and CCA responses to adenosine. A metabolic stable analog of adenosine, 2Cl-adenosine, exerted higher inhibition on CCA cell growth. The disturbance in intracellular AMP level also led to an activation of 5′ AMP-activated protein kinase (AMPK). Accordingly, we proposed a novel adenosine-mediated cancer cell growth and invasion suppression via a receptor-independent mechanism in CCA.

scholarly journals The Interplay of HIV and Autophagy in Early Infection

2021 ◽  
Vol 12 ◽  
Author(s):  
Romina Cabrera-Rodríguez ◽  
Silvia Pérez-Yanes ◽  
Judith Estévez-Herrera ◽  
Daniel Márquez-Arce ◽  
Cecilia Cabrera ◽  
...  
Keyword(s):  
Viral Replication ◽  
Viral Infection ◽  
Molecular Mechanisms ◽  
New Drugs ◽  
Clinical Progression ◽  
Virus Binding ◽  
Advanced Therapies ◽  
Health Communities ◽  
Global Threat ◽  
Hiv 1

HIV/AIDS is still a global threat despite the notable efforts made by the scientific and health communities to understand viral infection, to design new drugs or to improve existing ones, as well as to develop advanced therapies and vaccine designs for functional cure and viral eradication. The identification and analysis of HIV-1 positive individuals that naturally control viral replication in the absence of antiretroviral treatment has provided clues about cellular processes that could interact with viral proteins and RNA and define subsequent viral replication and clinical progression. This is the case of autophagy, a degradative process that not only maintains cell homeostasis by recycling misfolded/old cellular elements to obtain nutrients, but is also relevant in the innate and adaptive immunity against viruses, such as HIV-1. Several studies suggest that early steps of HIV-1 infection, such as virus binding to CD4 or membrane fusion, allow the virus to modulate autophagy pathways preparing cells to be permissive for viral infection. Confirming this interplay, strategies based on autophagy modulation are able to inhibit early steps of HIV-1 infection. Moreover, autophagy dysregulation in late steps of the HIV-1 replication cycle may promote autophagic cell-death of CD4+ T cells or control of HIV-1 latency, likely contributing to disease progression and HIV persistence in infected individuals. In this scenario, understanding the molecular mechanisms underlying HIV/autophagy interplay may contribute to the development of new strategies to control HIV-1 replication. Therefore, the aim of this review is to summarize the knowledge of the interplay between autophagy and the early events of HIV-1 infection, and how autophagy modulation could impair or benefit HIV-1 infection and persistence, impacting viral pathogenesis, immune control of viral replication, and clinical progression of HIV-1 infected patients.

scholarly journals Virion-incorporated PSGL-1 and CD43 inhibit both cell-free infection and transinfection of HIV-1 by preventing virus–cell binding

2020 ◽  
Vol 117 (14) ◽  
pp. 8055-8063 ◽  
Author(s):  
Tomoyuki Murakami ◽  
Nancy Carmona ◽  
Akira Ono
Keyword(s):  
T Cells ◽  
Plasma Membrane ◽  
Cell Attachment ◽  
Transmembrane Proteins ◽  
Inhibitory Effect ◽  
Lymphoid Organ ◽  
Cell Surface Expression ◽  
Structural Protein ◽  
Virion Incorporation ◽  
Hiv 1

HIV-1 particles incorporate various host transmembrane proteins in addition to viral Env glycoprotein during assembly at the plasma membrane. In polarized T cells, HIV-1 structural protein Gag localizes to the plasma membrane of uropod, a rear-end protrusion. Notably, uropod transmembrane proteins PSGL-1 and CD43 cocluster specifically with Gag assembling at the plasma membrane even in cells that do not form uropods. Recent reports have shown that expression of either PSGL-1 or CD43 in virus-producing cells reduces the infectivity of progeny virions and that HIV-1 infection reduces the cell surface expression of these proteins. However, the mechanisms for both processes remain to be determined. In this study, we found that virion incorporation of PSGL-1 and CD43 closely correlates with diminished virion infectivity. PSGL-1 and CD43 inhibited virus attachment to CD4+cells irrespective of the presence of Env. These proteins also inhibited virion attachment to CD4−lymphoid organ fibroblastic reticular cells that mediate transinfection of CD4+T cells. Consistent with the possibility that highly extended extracellular domains of these proteins physically block virus–cell attachment, the inhibitory effect of PSGL-1 required its full-length ectodomain. HIV-1 encoding Gag mutants that are defective in either coclustering with these host proteins or ESCRT-dependent particle release failed to reduce PSGL-1 on surface of infected cells. This study reveals an anti–HIV-1 mechanism that suppresses virus–cell attachment and a previously unappreciated process of HIV-1-mediated down-regulation of host antiviral proteins, both of which likely require virion incorporation of these proteins.

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