scholarly journals The Kaposi's Sarcoma-Associated Herpesvirus K5 E3 Ubiquitin Ligase Modulates Targets by Multiple Molecular Mechanisms

2007 ◽  
Vol 81 (12) ◽  
pp. 6573-6583 ◽  
Author(s):  
Robert E. Means ◽  
Sabine M. Lang ◽  
Jae U. Jung
Keyword(s):  
Cell Surface ◽  
Ubiquitin Ligase ◽  
Kaposi's Sarcoma ◽  
E3 Ubiquitin Ligase ◽  
Kaposi’S Sarcoma ◽  
Down Regulation ◽  
Class I Mhc ◽  
Mhc I ◽  
Kaposi's Sarcoma Associated Herpesvirus ◽  
Kaposi’S Sarcoma Associated Herpesvirus

ABSTRACT Kaposi's sarcoma-associated herpesvirus encodes two highly related membrane-associated, RING-CH-containing (MARCH) family E3 ubiquitin ligases, K3 and K5, that can down regulate a variety of cell surface proteins through enhancement of their endocytosis and degradation. In this report we present data that while K5 modulation of major histocompatibility complex class I (MHC-I) closely mirrors the mechanisms used by K3, alternative molecular pathways are utilized by this E3 ligase in the down regulation of intercellular adhesion molecule 1 (ICAM-1) and B7.2. Internalization assays demonstrate that down regulation of each target can occur through increased endocytosis from the cell surface. However, mutation of a conserved tyrosine-based endocytosis motif in K5 resulted in a protein lacking the ability to direct an increased rate of MHC-I or ICAM-1 internalization but still able to down regulate B7.2 in a ubiquitin-dependent but endocytosis-independent manner. Further, mutation of two acidic clusters abolished K5-mediated MHC-I degradation while only slightly decreasing ICAM-1 or B7.2 protein destruction. This same mutant abolished detectable ubiquitylation of all targets. These data indicate that while K5 can act as an E3 ubiquitin ligase to directly mediate cell surface molecule destruction, regulation of its targets occurs through multiple pathways, including ubiquitin-independent mechanisms.

scholarly journals The Specificities of Kaposi's Sarcoma-Associated Herpesvirus-Encoded E3 Ubiquitin Ligases Are Determined by the Positions of Lysine or Cysteine Residues within the Intracytoplasmic Domains of Their Targets

2008 ◽  
Vol 82 (8) ◽  
pp. 4184-4189 ◽  
Author(s):  
Ken Cadwell ◽  
Laurent Coscoy
Keyword(s):  
Kaposi's Sarcoma ◽  
Transmembrane Domain ◽  
Kaposi’S Sarcoma ◽  
Cysteine Residues ◽  
Dependent Manner ◽  
Class I Mhc ◽  
Mhc I ◽  
E3 Ligases ◽  
Kaposi's Sarcoma Associated Herpesvirus ◽  
Kaposi’S Sarcoma Associated Herpesvirus

ABSTRACT Kaposi's sarcoma-associated herpesvirus encodes two homologous E3 ligases, MIR1 and MIR2, that mediate the ubiquitination and subsequent downregulation of several cell surface proteins, and in particular major histocompatibility complex class I (MHC-I) molecules. We have previously shown that, in addition to lysine ubiquitination, MIR1 has the unique ability of transferring ubiquitin onto MHC-I molecules lacking available lysine residues, in a cysteine-dependent manner. Here we report that MIR1 activity is maximal when either a lysine or cysteine residue is placed approximately 15 amino acids away from the transmembrane domain, whereas MIR2 preferentially targets residues, including cysteines, that are closer to the transmembrane domain. Thus MIR1 and -2 can distinguish their substrates based on the position of the lysine or cysteine residues, suggesting that these proteins have evolved to target different sets of surface molecules. These results indicate that the position of target residues within a substrate is an essential determinant of E3 ubiquitin ligase specificity.

scholarly journals An Insight Into The Role of E3 ubiquitin Ligase c-Cbl, ESCRT Machinery and Host Cell Signaling in Kaposi's Sarcoma-Associated Herpesvirus (KSHV) Entry and Trafficking

2017 ◽  
pp. JVI.01376-17 ◽  
Author(s):  
Binod Kumar ◽  
Arunava Roy ◽  
Mohanan Valiya Veettil ◽  
Bala Chandran
Keyword(s):  
Host Cell ◽  
Ubiquitin Ligase ◽  
Kaposi's Sarcoma ◽  
E3 Ubiquitin Ligase ◽  
Kaposi’S Sarcoma ◽  
Host Protein ◽  
Cell Surface Receptor ◽  
Signal Molecules ◽  
Kaposi's Sarcoma Associated Herpesvirus ◽  
Kaposi’S Sarcoma Associated Herpesvirus

Kaposi's sarcoma-associated herpesvirus (KSHV)in vitroinfection of dermal endothelial cell begins with its binding to host cell surface receptor molecules such as heparan sulfate (HS), integrins (α3β1, αVβ3 and αVβ5), xCT and EphA2 receptor tyrosine kinase (EphA2R). These initial events initiate dynamic host protein-protein interactions involving a multi-molecular complex of receptors, signal molecules (FAK, Src, PI3-K, RhoA-GTPase), adaptors (c-Cbl, CIB1, Crk, p130Cas and GEF-C3G), and actin/myosin II light chain that leads to virus entry via macropinocytosis. Here we discuss how KSHV hijacks c-Cbl, an E3 ubiquitin ligase, to monoubiquitinate the receptors/actin which acts like markers for trafficking (similar to zip codes), resulting in the recruitment of the members of the host endosomal sorting complexes required for transport (ESCRT) Hrs, Tsg101, EAP45, CHMP 5 and 6 proteins (zip code readers) recognizing the ubiquitinated proteins and adaptors machinery to traffic through the different endosomal compartments in the cytoplasm to initiate the macropinocytic process and infection.

scholarly journals Construction and Manipulation of a New Kaposi's Sarcoma-Associated Herpesvirus Bacterial Artificial Chromosome Clone

2012 ◽  
Vol 86 (18) ◽  
pp. 9708-9720 ◽  
Author(s):  
Kevin F. Brulois ◽  
Heesoon Chang ◽  
Amy Si-Ying Lee ◽  
Armin Ensser ◽  
Lai-Yee Wong ◽  
...  
Keyword(s):  
Bacterial Artificial Chromosome ◽  
Kaposi's Sarcoma ◽  
Kaposi’S Sarcoma ◽  
Artificial Chromosome ◽  
Surface Expression ◽  
Class I Mhc ◽  
Mhc I ◽  
E3 Ligases ◽  
Kaposi's Sarcoma Associated Herpesvirus ◽  
Kaposi’S Sarcoma Associated Herpesvirus

Efficient genetic modification of herpesviruses such as Kaposi's sarcoma-associated herpesvirus (KSHV) has come to rely on bacterial artificial chromosome (BAC) technology. In order to facilitate this approach, we generated a new KSHV BAC clone, called BAC16, derived from the rKSHV.219 virus, which stems from KSHV and Epstein-Barr virus-coinfected JSC1 primary effusion lymphoma (PEL) cells. Restriction enzyme and complete sequencing data demonstrate that the KSHV of JSC1 PEL cells showed a minimal level of sequence variation across the entire viral genome compared to the complete genomic sequence of other KSHV strains. BAC16 not only stably propagated in bothEscherichia coliand mammalian cells without apparent genetic rearrangements, but also was capable of robustly producing infectious virions (∼5 × 107/ml). We also demonstrated the utility of BAC16 by generating deletion mutants of either the K3 or K5 genes, whose products are E3 ligases of the membrane-associated RING-CH (MARCH) family. While previous studies have shown that individual expression of either K3 or K5 results in efficient downregulation of the surface expression of major histocompatibility complex class I (MHC-I) molecules, we found that K5, but not K3, was the primary factor critical for the downregulation of MHC-I surface expression during KSHV lytic reactivation or followingde novoinfection. The data presented here demonstrate the utility of BAC16 for the generation and characterization of KSHV knockout and mutant recombinants and further emphasize the importance of functional analysis of viral genes in the context of the KSHV genome besides the study of individual gene expression.

scholarly journals Kaposi's Sarcoma-Associated Herpesvirus LANA Modulates the Stability of the E3 Ubiquitin Ligase RLIM

2019 ◽  
Vol 94 (5) ◽  
Author(s):  
Hagar Tadmor ◽  
Melanie Greenway ◽  
Anuj Ahuja ◽  
Ola Orgil ◽  
Gangling Liao ◽  
...  
Keyword(s):  
Ubiquitin Ligase ◽  
Kaposi's Sarcoma ◽  
E3 Ubiquitin Ligase ◽  
Ring Finger ◽  
Kaposi’S Sarcoma ◽  
Interacting Protein ◽  
Transcription Regulators ◽  
Kaposi's Sarcoma Associated Herpesvirus ◽  
The Stability ◽  
Kaposi’S Sarcoma Associated Herpesvirus

ABSTRACT The Kaposi’s sarcoma-associated herpesvirus (KSHV)-encoded latency-associated nuclear antigen (LANA) protein functions in latently infected cells as an essential participant in KSHV genome replication and as a driver of dysregulated cell growth. In a previous study, we have identified LANA-interacting proteins using a protein array screen. Here, we explore the effect of LANA on the stability and activity of RLIM (RING finger LIM-domain-interacting protein, encoded by the RNF12 gene), a novel LANA-interacting protein identified in that protein screen. RLIM is an E3 ubiquitin ligase that leads to the ubiquitination and degradation of several transcription regulators, such as LMO2, LMO4, LHX2, LHX3, LDB1, and the telomeric protein TRF1. Expression of LANA leads to downregulation of RLIM protein levels. This LANA-mediated RLIM degradation is blocked in the presence of the proteasome inhibitor, MG132. Therefore, the interaction between LANA and RLIM could be detected in coimmunoprecipitation assay only in the presence of MG132 to prevent RLIM degradation. A RING finger mutant RLIM is resistant to LANA-mediated degradation, suggesting that LANA promotes RLIM autoubiquitination. Interestingly, we found that LANA enhanced the degradation of some RLIM substrates, such as LDB1 and LMO2, and prevented RLIM-mediated degradation of others, such as LHX3 and TRF1. We also show that transcription regulation by RLIM substrates is modulated by LANA. RLIM substrates are assembled into multiprotein transcription regulator complexes that regulate the expression of many cellular genes. Therefore, our study identified another way KSHV can modulate cellular gene expression. IMPORTANCE E3 ubiquitin ligases mark their substrates for degradation and therefore control the cellular abundance of their substrates. RLIM is an E3 ubiquitin ligase that leads to the ubiquitination and degradation of several transcription regulators, such as LMO2, LMO4, LHX2, LHX3, LDB1, and the telomeric protein TRF1. Here, we show that the Kaposi’s sarcoma-associated herpesvirus (KSHV)-encoded LANA protein enhances the ubiquitin ligase activity of RLIM, leading to enhanced RLIM autoubiquitination and degradation. Interestingly, LANA enhanced the degradation of some RLIM substrates, such as LDB1 and LMO2, and prevented RLIM-mediated degradation of others, such as LHX3 and TRF1. In agreement with protein stability of RLIM substrates, we found that LANA modulates transcription by LHX3-LDB1 complex and suggest additional ways LANA can modulate cellular gene expression. Our study adds another way a viral protein can regulate cellular protein stability, by enhancing the autoubiquitination and degradation of an E3 ubiquitin ligase.

Kaposi’s sarcoma-associated herpesvirus ubiquitin ligases downregulate cell surface expression of l-selectin

2021 ◽  
Vol 102 (11) ◽  
Author(s):  
Mizuho Kajikawa ◽  
Nanae Imaizumi ◽  
Shiho Machii ◽  
Tomoka Nakamura ◽  
Nana Harigane ◽  
...  
Keyword(s):  
Cell Surface ◽  
Nk Cells ◽  
Immune Evasion ◽  
Kaposi's Sarcoma ◽  
Kaposi’S Sarcoma ◽  
Ubiquitin Ligases ◽  
Surface Expression ◽  
Cell Surface Expression ◽  
Kaposi's Sarcoma Associated Herpesvirus ◽  
Kaposi’S Sarcoma Associated Herpesvirus

Kaposi’s sarcoma-associated herpesvirus (KSHV) is an oncogenic etiological factor for Kaposi’s sarcoma and primary effusion lymphoma in immunocompromised patients. KSHV utilizes two immune evasion E3 ubiquitin ligases, namely K3 and K5, to downregulate the expression of antigen-presenting molecules and ligands of natural killer (NK) cells in the host cells through an ubiquitin-dependent endocytic mechanism. This allows the infected cells to evade surveillance and elimination by cytotoxic lymphocytes and NK cells. The number of host cell molecular substrates reported for these ubiquitin ligases is limited. The identification of novel substrates for these ligases will aid in elucidating the mechanism underlying immune evasion of KSHV. This study demonstrated that K5 downregulated the cell surface expression of l-selectin, a C-type lectin-like adhesion receptor expressed in the lymphocytes. Tryptophan residue located at the centre of the E2-binding site in the K5 RINGv domain was essential to downregulate l-selectin expression. Additionally, the lysine residues located at the cytoplasmic tail of l-selectin were required for the K5-mediated downregulation of l-selectin. K5 promoted the degradation of l-selectin through polyubiquitination. These results suggest that K5 downregulates l-selectin expression on the cell surface by promoting polyubiquitination and ubiquitin-dependent endocytosis, which indicated that l-selectin is a novel substrate for K5. Additionally, K3 downregulated l-selectin expression. The findings of this study will aid in the elucidation of a novel immune evasion mechanism in KSHV.

scholarly journals Kaposi's Sarcoma-Associated Herpesvirus Viral Interferon Regulatory Factor 4 Targets MDM2 To Deregulate the p53 Tumor Suppressor Pathway

2009 ◽  
Vol 83 (13) ◽  
pp. 6739-6747 ◽  
Author(s):  
Hye-Ra Lee ◽  
Zsolt Toth ◽  
Young C. Shin ◽  
Jong-Soo Lee ◽  
Heesoon Chang ◽  
...  
Keyword(s):  
Cell Growth ◽  
Tumor Suppressor ◽  
Viral Replication ◽  
Ubiquitin Ligase ◽  
Kaposi's Sarcoma ◽  
E3 Ubiquitin Ligase ◽  
Growth Control ◽  
Kaposi’S Sarcoma ◽  
Kaposi’S Sarcoma Associated Herpesvirus ◽  
Cell Growth Control

ABSTRACT Cells infected by viruses utilize interferon (IFN)-mediated and p53-mediated irreversible cell cycle arrest and apoptosis as part of the overall host surveillance mechanism to ultimately block viral replication and dissemination. Viruses, in turn, have evolved elaborate mechanisms to subvert IFN- and p53-mediated host innate immune responses. Kaposi's sarcoma-associated herpesvirus (KSHV) encodes several viral IFN regulatory factors (vIRF1 to vIRF4) within a cluster of loci, their functions being primarily to inhibit host IFN-mediated innate immunity and deregulate p53-mediated cell growth control. Despite its significant homology and similar genomic location to other vIRFs, vIRF4 is distinctive, as it does not target and antagonize host IFN-mediated signal transduction. Here, we show that KSHV vIRF4 interacts with the murine double minute 2 (MDM2) E3 ubiquitin ligase, leading to the reduction of p53, a tumor suppressor, via proteasome-mediated degradation. The central region of vIRF4 is required for its interaction with MDM2, which led to the suppression of MDM2 autoubiquitination and, thereby, a dramatic increase in MDM2 stability. Consequently, vIRF4 expression markedly enhanced p53 ubiquitination and degradation, effectively suppressing p53-mediated apoptosis. These results indicate that KSHV vIRF4 targets and stabilizes the MDM2 E3 ubiquitin ligase to facilitate the proteasome-mediated degradation of p53, perhaps to circumvent host growth surveillance and facilitate viral replication in infected cells. Taken together, the indications are that the downregulation of p53-mediated cell growth control is a common characteristic of the four KSHV vIRFs and that p53 is indeed a key factor in the host's immune surveillance program against viral infections.

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