scholarly journals The broad anti-viral agent glycyrrhizin directly modulates the fluidity of plasma membrane and HIV-1 envelope

2005 ◽  
Vol 392 (1) ◽  
pp. 191-199 ◽  
Author(s):  
Shinji Harada
Keyword(s):  
Plasma Membrane ◽  
Membrane Fluidity ◽  
Viral Envelope ◽  
Cell Entry ◽  
Cell Leukaemia ◽  
Fusion Pore ◽  
Type I ◽  
Viral Agent ◽  
Leukaemia Virus ◽  
Hiv 1

Cell entry of enveloped viruses requires a wide-fusion-pore mechanism, involving clustering of fusion-activated proteins and fluidization of the plasma membrane and viral envelope. In the present study, GL (glycyrrhizin) is reported to lower membrane fluidity, thus suppressing infection by HIV, influenza A virus and vesicular stomatitis virus, but not by poliovirus. GL-treated HIV-1 particles showed reduced infectivity. GL also inhibited cell-to-cell fusion induced by HIV-1 and HTLV-I (human T-cell leukaemia virus type I). However, when cells treated with 1 mg/ml GL were placed in GL-free medium, they showed increased susceptibility to HIV-1 infection and HTLV-I fusion due to enhancement of membrane fluidity. The membrane dependence of GL and GL removal experiments suggest that GL does affect the cell entry of viruses. HIVs with more gp120 were less dependent on temperature and less sensitive to GL treatment than those with less gp120, indicating that the existence of more gp120 molecules resulted in a higher probability of forming a cluster of fusion-activated proteins.

scholarly journals HIV protease cleaves poly(A)-binding protein

2006 ◽  
Vol 396 (2) ◽  
pp. 219-226 ◽  
Author(s):  
Enrique Álvarez ◽  
Alfredo Castelló ◽  
Luis Menéndez-Arias ◽  
Luis Carrasco
Keyword(s):  
Binding Protein ◽  
Cellular Protein ◽  
Hiv Protease ◽  
Cell Leukaemia ◽  
Type I ◽  
Free System ◽  
Leukaemia Virus ◽  
Human T Cell ◽  
Recognition Motifs ◽  
Hiv 1

The PABP [poly(A)-binding protein] is able to interact with the 3′ poly(A) tail of eukaryotic mRNA, promoting its translation. Cleavage of PABP by viral proteases encoded by several picornaviruses and caliciviruses plays a role in the abrogation of cellular protein synthesis. We report that infection of MT-2 cells with HIV-1 leads to efficient proteolysis of PABP. Analysis of PABP integrity was carried out in BHK-21 (baby-hamster kidney) and COS-7 cells upon individual expression of the protease from several members of the Retroviridae family, e.g. MoMLV (Moloney murine leukaemia virus), MMTV (mouse mammary tumour virus), HTLV-I (human T-cell leukaemia virus type I), SIV (simian immunodeficiency virus), HIV-1 and HIV-2. Moreover, protease activity against PABP was tested in a HeLa-cell-free system. Only MMTV, HIV-1 and HIV-2 proteases were able to cleave PABP in the absence of other viral proteins. Purified HIV-1 and HIV-2 proteases cleave PABP1 directly at positions 237 and 477, separating the two first RNA-recognition motifs from the C-terminal domain of PABP. An additional cleavage site located at position 410 was detected for HIV-2 protease. These findings indicate that some retroviruses may share with picornaviruses and caliciviruses the capacity to proteolyse PABP.

Protective effect of interferon ? on human T cell leukaemia virus type I infection of CD4+ T cells isolated from human cord blood

1993 ◽  
Vol 37 (2) ◽  
pp. 97-104 ◽  
Author(s):  
Beatrice Macchi ◽  
Isabella Faraoni ◽  
Antonio Mastino ◽  
Chiara D'Onofrio ◽  
Gianna Romeo ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Protective Effect ◽  
Cord Blood ◽  
Virus Type ◽  
Cell Leukaemia ◽  
Type I ◽  
Human Cord Blood ◽  
Leukaemia Virus ◽  
Human T Cell

NEGATIVE ASSOCIATION BETWEEN THE HUMAN T-CELL LEUKAEMIA VIRUS TYPE I AND LARGE GRANULAR LYMPHOCYTE LEUKAEMIA IN JAPAN

The Lancet ◽  
1988 ◽  
Vol 332 (8617) ◽  
pp. 962 ◽  
Author(s):  
Nobutaka Imamura ◽  
Atsushi Kuramoto ◽  
Keisei Kawa-Ha ◽  
Hiroshi Fujii ◽  
Tomoo Takiguchi
Keyword(s):  
T Cell ◽  
Virus Type ◽  
Negative Association ◽  
Large Granular Lymphocyte ◽  
Cell Leukaemia ◽  
Type I ◽  
Leukaemia Virus ◽  
Human T Cell ◽  
Large Granular Lymphocyte Leukaemia

scholarly journals Plasma Membrane-Associated Restriction Factors and Their Counteraction by HIV-1 Accessory Proteins

Cells ◽  
2019 ◽  
Vol 8 (9) ◽  
pp. 1020 ◽  
Author(s):  
Ramirez ◽  
Sharma ◽  
Singh ◽  
Stoneham ◽  
Vollbrecht ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Membrane Trafficking ◽  
Immune Surveillance ◽  
Viral Envelope ◽  
Accessory Proteins ◽  
Host Defenses ◽  
Restriction Factors ◽  
Associated Proteins ◽  
Infected Cells ◽  
Hiv 1

The plasma membrane is a site of conflict between host defenses and many viruses. One aspect of this conflict is the host’s attempt to eliminate infected cells using innate and adaptive cell-mediated immune mechanisms that recognize features of the plasma membrane characteristic of viral infection. Another is the expression of plasma membrane-associated proteins, so-called restriction factors, which inhibit enveloped virions directly. HIV-1 encodes two countermeasures to these host defenses: The membrane-associated accessory proteins Vpu and Nef. In addition to inhibiting cell-mediated immune-surveillance, Vpu and Nef counteract membrane-associated restriction factors. These include BST-2, which traps newly formed virions at the plasma membrane unless counteracted by Vpu, and SERINC5, which decreases the infectivity of virions unless counteracted by Nef. Here we review key features of these two antiviral proteins, and we review Vpu and Nef, which deplete them from the plasma membrane by co-opting specific cellular proteins and pathways of membrane trafficking and protein-degradation. We also discuss other plasma membrane proteins modulated by HIV-1, particularly CD4, which, if not opposed in infected cells by Vpu and Nef, inhibits viral infectivity and increases the sensitivity of the viral envelope glycoprotein to host immunity.

Effects of membrane lipid and fluidity modifications on HIV-1 infectibility of primate lymphocytes in vitro

1990 ◽  
Vol 10 (3) ◽  
pp. 263-270 ◽  
Author(s):  
J. Pascal Zimmer ◽  
Hans A. Lehr ◽  
Christoph Hübner ◽  
Stephan G. Lindner ◽  
Ralf Ramsperger ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Membrane Fluidity ◽  
Lipid Composition ◽  
Membrane Lipid ◽  
Serum Factors ◽  
Membrane Lipid Composition ◽  
Plasma Membrane Lipid ◽  
Hiv 1

Although most non-human primates, except the chimpanzee and the gibbon in vivo are not infectible by HIV-1, lymphocytes of several of these species can be infected by HIV-1 in vitro.In order to investigate whether the in vitro infectibility of primate lymphocytes might be attributed to plasma membrane adaptation processes or to serum factors, we compared HIV-1 infectibility of cultivated peripheral blood lymphocytes of macaques and of baboons on day one and on day ten of cultivation. These data were correlated to plasma membrane lipid composition and membrane fluidity.We found a correlation between increased HIV-1 in vitro infectibility and changes in plasma membrane lipid composition resulting in decreased membrane fluidity of cultured primate lymphocytes.

Plasma Membrane Fluidity and Polarity of Polymorphonuclear Leukocytes from Children with Type I Diabetes Mellitus

1999 ◽  
Vol 13 (5-6) ◽  
pp. 243-250 ◽  
Author(s):  
Ahmad Kantar ◽  
Gian Paolo Littarru ◽  
Giancarlo Falcioni ◽  
Valentino Cherubini ◽  
Giovanni Valentino Coppa ◽  
...  
Keyword(s):  
Diabetes Mellitus ◽  
Plasma Membrane ◽  
Membrane Fluidity ◽  
Polymorphonuclear Leukocytes ◽  
Type I Diabetes ◽  
Type I Diabetes Mellitus ◽  
Type I ◽  
Plasma Membrane Fluidity

scholarly journals Sphingomyelin Synthase 2, but Not Sphingomyelin Synthase 1, Is Involved in HIV-1 Envelope-mediated Membrane Fusion

2014 ◽  
Vol 289 (44) ◽  
pp. 30842-30856 ◽  
Author(s):  
Yasuhiro Hayashi ◽  
Yoko Nemoto-Sasaki ◽  
Takashi Tanikawa ◽  
Saori Oka ◽  
Kiyoto Tsuchiya ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Membrane Fusion ◽  
Actin Polymerization ◽  
Plasma Membranes ◽  
Viral Envelope ◽  
Target Cells ◽  
Nonreceptor Tyrosine Kinase ◽  
Sphingomyelin Synthase ◽  
A Cell ◽  
Hiv 1

Membrane fusion between the viral envelope and plasma membranes of target cells has previously been correlated with HIV-1 infection. Lipids in the plasma membrane, including sphingomyelin, may be crucially involved in HIV-1 infection; however, the role of lipid-metabolic enzymes in membrane fusion remains unclear. In this study, we examined the roles of sphingomyelin synthase (SMS) in HIV-1 Env-mediated membrane fusion using a cell-cell fusion assay with HIV-1 mimetics and their target cells. We employed reconstituted cells as target cells that stably express Sms1 or Sms2 in Sms-deficient cells. Fusion susceptibility was ∼5-fold higher in Sms2-expressing cells (not in Sms1-expressing cells) than in Sms-deficient cells. The enhancement of fusion susceptibility observed in Sms2-expressing cells was reversed and reduced by Sms2 knockdown. We also found that catalytically nonactive Sms2 promoted membrane fusion susceptibility. Moreover, SMS2 co-localized and was constitutively associated with the HIV receptor·co-receptor complex in the plasma membrane. In addition, HIV-1 Env treatment resulted in a transient increase in nonreceptor tyrosine kinase (Pyk2) phosphorylation in Sms2-expressing and catalytically nonactive Sms2-expressing cells. We observed that F-actin polymerization in the region of membrane fusion was more prominent in Sms2-expressing cells than Sms-deficient cells. Taken together, our research provides insight into a novel function of SMS2 which is the regulation of HIV-1 Env-mediated membrane fusion via actin rearrangement.

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