scholarly journals Differential Dependence of the Infectivity of HIV-1 Group O Isolates on the Cellular Protein Cyclophilin A

Virology ◽  
2002 ◽  
Vol 294 (2) ◽  
pp. 289-295 ◽  
Author(s):  
Klaus Wiegers ◽  
Hans-Georg Kräusslich
Keyword(s):  
Cyclophilin A ◽  
Cellular Protein ◽  
Hiv 1

HIV-1 p6—Another viral interaction partner to the host cellular protein cyclophilin A

2012 ◽  
Vol 1824 (4) ◽  
pp. 667-678 ◽  
Author(s):  
Sara M.Ø. Solbak ◽  
Tove R. Reksten ◽  
Rene Röder ◽  
Victor Wray ◽  
Ole Horvli ◽  
...  
Keyword(s):  
Cyclophilin A ◽  
Cellular Protein ◽  
Interaction Partner ◽  
Hiv 1 ◽  
Host Cellular Protein

scholarly journals Selection for Loss of Ref1 Activity in Human Cells Releases Human Immunodeficiency Virus Type 1 from Cyclophilin A Dependence during Infection

2004 ◽  
Vol 78 (21) ◽  
pp. 12066-12070 ◽  
Author(s):  
David M. Sayah ◽  
Jeremy Luban
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Mammalian Cells ◽  
Leukemia Virus ◽  
Cyclophilin A ◽  
Cellular Protein ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Capsid (CA)-specific restrictions are determinants of retroviral tropism in mammalian cells. One such restriction, human Ref1, targets strains of murine leukemia virus bearing an arginine at CA residue 110 (N-MLV), resulting in decreased accumulation of viral cDNA. The cellular factors accounting for Ref1 activity are unknown. As2O3 increases N-MLV titer in Ref1-positive cells, possibly by counteracting Ref1. Restriction factor saturation experiments suggest that Ref1 may also target human immunodeficiency virus type 1 (HIV-1), but only if its CA is not bound to the cellular protein cyclophilin A (CypA). As a step towards understanding the genetic determinants of Ref1, we subjected Ref1-positive TE671 cells to three sequential rounds of selection with N-MLV reporter viruses. We isolated a subclone, 17H1, that was permissive for N-MLV infection and therefore deficient in Ref1 activity. Stimulation of N-MLV replication by As2O3 was attenuated in 17H1, confirming that the drug acts by overcoming Ref1 activity. HIV-1 infection of 17H1 cells was resistant to disruption of the CA-CypA interaction, demonstrating that Ref1 restricts CypA-free HIV-1. Our results suggest that interaction with CypA evolved to protect HIV-1 from this human antiviral activity.

scholarly journals Cyclophilin A protects HIV-1 from restriction by human TRIM5α

2019 ◽  
Author(s):  
Kyusik Kim ◽  
Ann Dauphin ◽  
Sevnur Komurlu ◽  
Leonid Yurkovetskiy ◽  
William E. Diehl ◽  
...  
Keyword(s):  
Reverse Transcription ◽  
Cyclophilin A ◽  
Cellular Protein ◽  
Human Cells ◽  
Sub Saharan Africa ◽  
Restriction Factor ◽  
Target Cells ◽  
Chromosomal Dna ◽  
Sub Saharan ◽  
Hiv 1

The capsid (CA) protein lattice of HIV-1 and other retroviruses encases viral genomic RNA and regulates steps that are essential to retroviral invasion of target cells, including reverse transcription, nuclear trafficking, and integration of viral cDNA into host chromosomal DNA1. Cyclophilin A (CypA), the first cellular protein reported to bind HIV-1 CA2, has interacted with invading lentiviruses related to HIV-1 for millions of years3–7. Disruption of the CA-CypA interaction decreases HIV-1 infectivity in human cells8–12, but stimulates infectivity in non-human primate cells13–15. Genetic and biochemical data suggest that CypA interaction with CA protects HIV-1 from a restriction factor in human cells16–20. Discovery of the CA-specific restriction factor TRIM5α21, and of TRIM5-CypA fusion genes that were independently generated at least four times in phylogeny4,5,15,22–25, pointed to human TRIM5α as the CypA-sensitive restriction factor. However, significant HIV-1 restriction by human TRIM5α21, let alone inhibition of such activity by CypA26, has not been detected. Here, exploiting reverse genetic tools optimized for primary human CD4+T cells, macrophages, and dendritic cells, we demonstrate that disruption of the CA-CypA interaction renders HIV-1 susceptible to restriction by human TRIM5α, with the block occurring before reverse transcription. Identical findings were obtained with single-cycle vectors or with replication-competent HIV-1, including sexually-transmitted clones from sub-Saharan Africa. Endogenous TRIM5α was observed to associate with virion cores as they entered the macrophage cytoplasm, but only when the CA-CypA interaction was disrupted. These experiments resolve the long-standing mystery of the role of CypA in HIV-1 replication by demonstrating that this ubiquitous cellular protein shields HIV-1 from previously inapparent, but potent inhibition, imposed by human TRIM5α. Hopefully this reinvigorates development of CypA-inhibitors for treatment of HIV-1 and other CypA-dependent pathogens27–30.

scholarly journals SUN1 Regulates HIV-1 Nuclear Import in a Manner Dependent on the Interaction between the Viral Capsid and Cellular Cyclophilin A

2018 ◽  
Vol 92 (13) ◽  
pp. e00229-18 ◽  
Author(s):  
Xinlong Luo ◽  
Wei Yang ◽  
Guangxia Gao
Keyword(s):  
Nuclear Pore Complex ◽  
Nuclear Import ◽  
Leukemia Virus ◽  
Cyclophilin A ◽  
Cellular Protein ◽  
Wild Type Virus ◽  
Nuclear Pore ◽  
Nuclear Entry ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACTHuman immunodeficiency virus type 1 (HIV-1) can infect nondividing cells via passing through the nuclear pore complex. The nuclear membrane-imbedded protein SUN2 was recently reported to be involved in the nuclear import of HIV-1. Whether SUN1, which shares many functional similarities with SUN2, is involved in this process remained to be explored. Here we report that overexpression of SUN1 specifically inhibited infection by HIV-1 but not that by simian immunodeficiency virus (SIV) or murine leukemia virus (MLV). Overexpression of SUN1 did not affect reverse transcription but led to reduced accumulation of the 2-long-terminal-repeat (2-LTR) circular DNA and integrated viral DNA, suggesting a block in the process of nuclear import. HIV-1 CA was mapped as a determinant for viral sensitivity to SUN1. Treatment of SUN1-expressing cells with cyclosporine (CsA) significantly reduced the sensitivity of the virus to SUN1, and an HIV-1 mutant containing CA-G89A, which does not interact with cyclophilin A (CypA), was resistant to SUN1 overexpression. Downregulation of endogenous SUN1 inhibited the nuclear entry of the wild-type virus but not that of the G89A mutant. These results indicate that SUN1 participates in the HIV-1 nuclear entry process in a manner dependent on the interaction of CA with CypA.IMPORTANCEHIV-1 infects both dividing and nondividing cells. The viral preintegration complex (PIC) can enter the nucleus through the nuclear pore complex. It has been well known that the viral protein CA plays an important role in determining the pathways by which the PIC enters the nucleus. In addition, the interaction between CA and the cellular protein CypA has been reported to be important in the selection of nuclear entry pathways, though the underlying mechanisms are not very clear. Here we show that both SUN1 overexpression and downregulation inhibited HIV-1 nuclear entry. CA played an important role in determining the sensitivity of the virus to SUN1: the regulatory activity of SUN1 toward HIV-1 relied on the interaction between CA and CypA. These results help to explain how SUN1 is involved in the HIV-1 nuclear entry process.

scholarly journals The Cysteine Residues of HIV-1 Capsid Regulate Oligomerization and Cyclophilin A-Induced Changes

2005 ◽  
Vol 88 (3) ◽  
pp. 2078-2088 ◽  
Author(s):  
Marjorie Bon Homme ◽  
Carol Carter ◽  
Suzanne Scarlata
Keyword(s):  
Cyclophilin A ◽  
Cysteine Residues ◽  
Induced Changes ◽  
Hiv 1

scholarly journals Induction of TAK (Cyclin T1/P-TEFb) in Purified Resting CD4+ T Lymphocytes by Combination of Cytokines

2001 ◽  
Vol 75 (23) ◽  
pp. 11336-11343 ◽  
Author(s):  
Romi Ghose ◽  
Li-Ying Liou ◽  
Christine H. Herrmann ◽  
Andrew P. Rice
Keyword(s):  
T Lymphocytes ◽  
Rna Polymerase Ii ◽  
Interleukin 2 ◽  
Cellular Protein ◽  
Peripheral Blood Lymphocytes ◽  
Tat Protein ◽  
Necrosis Factor Alpha ◽  
Cyclin T1 ◽  
Protein Levels ◽  
Hiv 1

ABSTRACT Combinations of cytokines are known to reactivate transcription and replication of latent human immunodeficiency virus type 1 (HIV-1) proviruses in resting CD4+ T lymphocytes isolated from infected individuals. Transcription of the HIV-1 provirus by RNA polymerase II is strongly stimulated by the viral Tat protein. Tat function is mediated by a cellular protein kinase known as TAK (cyclin T1/P-TEFb) that is composed of Cdk9 and cyclin T1. We have found that treatment of peripheral blood lymphocytes and purified resting CD4+ T lymphocytes with the combination of interleukin-2 (IL-2), IL-6, and tumor necrosis factor alpha resulted in an increase in Cdk9 and cyclin T1 protein levels and an increase in TAK enzymatic activity. The cytokine induction of TAK in resting CD4+ T lymphocytes did not appear to require proliferation of lymphocytes. These results suggest that induction of TAK by cytokines secreted in the microenvironment of lymphoid tissue may be involved in the reactivation of HIV-1 in CD4+ T lymphocytes harboring a latent provirus.

scholarly journals MxB sensitivity of HIV-1 is determined by a highly variable and dynamic capsid surface

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Richard J Miles ◽  
Claire Kerridge ◽  
Laura Hilditch ◽  
Christopher Monit ◽  
David A Jacques ◽  
...  
Keyword(s):  
Nuclear Import ◽  
Cytotoxic T Lymphocyte ◽  
Cyclophilin A ◽  
Conformational Flexibility ◽  
Restriction Factors ◽  
Nuclear Entry ◽  
Linear Forms ◽  
Cofactor Binding ◽  
Cofactor Recruitment ◽  
Hiv 1

The type one interferon induced restriction factor Myxovirus resistance B (MxB) restricts HIV-1 nuclear entry evidenced by inhibition of 2-LTR but not linear forms of viral DNA. The HIV-1 capsid is the key determinant of MxB sensitivity and cofactor binding defective HIV-1 capsid mutants P90A (defective for cyclophilin A and Nup358 recruitment) and N74D (defective for CPSF6 recruitment) have reduced dependency on nuclear transport associated cofactors, altered integration targeting preferences and are not restricted by MxB expression. This has suggested that nuclear import mechanism may determine MxB sensitivity. Here we have use genetics to separate HIV-1 nuclear import cofactor dependence from MxB sensitivity. We provide evidence that MxB sensitivity depends on HIV-1 capsid conformation, rather than cofactor recruitment. We show that depleting CPSF6 to change nuclear import pathway does not impact MxB sensitivity, but mutants that recapitulate the effect of Cyclophilin A binding on capsid conformation and dynamics strongly impact MxB sensitivity. We demonstrate that HIV-1 primary isolates have different MxB sensitivities due to cytotoxic T lymphocyte (CTL) selected differences in Gag sequence but similar cofactor dependencies. Overall our work demonstrates a complex relationship between cyclophilin dependence and MxB sensitivity likely driven by CTL escape. We propose that cyclophilin binding provides conformational flexibility to HIV-1 capsid facilitating simultaneous evasion of capsid-targeting restriction factors including TRIM5 as well as MxB.

scholarly journals Phosphoserine acidic cluster motifs in the cytoplasmic domains of transmembrane proteins bind distinct basic regions on the μ subunits of clathrin adaptor protein complexes

2018 ◽  
Author(s):  
Rajendra Singh ◽  
Charlotte Stoneham ◽  
Christopher Lim ◽  
Xiaofei Jia ◽  
Javier Guenaga ◽  
...  
Keyword(s):  
Protein Trafficking ◽  
Transmembrane Proteins ◽  
Adaptor Protein ◽  
Cellular Protein ◽  
Membrane Lipid ◽  
Dependent Manner ◽  
Cytoplasmic Domains ◽  
Clathrin Adaptor ◽  
Hiv 1

AbstractProtein trafficking in the endosomal system involves the recognition of specific signals within the cytoplasmic domains (CDs) of transmembrane proteins by clathrin adaptors. One such signal is the phosphoserine acidic cluster (PSAC), the prototype of which is in the endoprotease Furin. How PSACs are recognized by clathrin adaptors has been controversial. We reported previously that HIV-1 Vpu, which modulates cellular immunoreceptors, contains a PSAC that binds to the µ subunits of clathrin adaptor protein (AP) complexes. Here, we show that the CD of Furin binds the µ subunits of AP-1 and AP-2 in a phosphorylation-dependent manner. Moreover, we identify a PSAC in a cytoplasmic loop of the cellular transmembrane Serinc3, an inhibitor of the infectivity of retroviruses. The two serines within the PSAC of Serinc3 are phosphorylated by casein kinase II and mediate interaction with the µ subunits in vitro. The sites of these serines vary among mammals in a manner consistent with host-pathogen conflict, yet the Serinc3-PSAC seems dispensible for anti-HIV activity and for counteraction by HIV-1 Nef. The CDs of Vpu, Furin, and the PSAC-containing loop of Serinc3 each bind the μ subunit of AP-2 (µ2) with similar affinities, but they appear to utilize different basic regions on µ2. The Serinc3 loop requires a region previously reported to bind the acidic plasma membrane lipid phosphatidylinositol-4,5-bisphosphate. These data suggest that the PSACs within different proteins recognize different basic regions on the µ surface, providing the potential to inhibit the activity of viral proteins without necessarily affecting cellular protein trafficking.

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