Tumorigenic Adenovirus Type 12 E1A Inhibits Phosphorylation of NF-κB by PKAc, Causing Loss of DNA Binding and Transactivation

ABSTRACT Human adenovirus type 12 (Ad12) E1A protein (E1A-12) is the key determinant of viral tumorigenesis. E1A-12 mediates major histocompatibility complex class I (MHC-I) shutoff by inhibiting the DNA binding of the transcriptional activator NF-κB (p50/p65) to the class I enhancer. This enables Ad12 tumorigenic cells to avoid class I recognition and lysis by cytotoxic T lymphocytes. In this study, we demonstrate that the phosphorylation of p50 and p65 by the catalytic subunit of protein kinase A (PKAc) is essential for NF-κB DNA binding and transactivation activity. Treatment with H89 and knockdown of PKAc in cells led to the inhibition of phosphorylation at p50 Ser337 and p65 Ser276 and loss of DNA binding by NF-κB. Importantly, NF-κB phosphorylation by PKAc was repressed by tumorigenic E1A-12, but not by nontumorigenic Ad5 E1A (E1A-5). The stable introduction of E1A-12 into Ad5 nontumorigenic cells resulted in a decrease in the phosphorylation of NF-κB, loss of NF-κB DNA binding, and the failure of NF-κB to activate a target promoter, as well as diminution of MHC-I transcription and cell surface expression. Significantly, the amount and enzymatic activity of PKAc were not altered in Ad12 tumorigenic cells relative to its amount and activity in nontumorigenic Ad5 cells. These results demonstrate that E1A-12 specifically prevents NF-κB from being phosphorylated by PKAc.

Download Full-text

Variations in MHC class I antigen presentation and immunopeptidome selection pathways

F1000Research ◽

10.12688/f1000research.26935.1 ◽

2020 ◽

Vol 9 ◽

pp. 1177

Author(s):

Anita J. Zaitouna ◽

Amanpreet Kaur ◽

Malini Raghavan

Keyword(s):

Cell Surface ◽

Antigen Presentation ◽

Surface Expression ◽

Structural Features ◽

Class I ◽

Cell Surface Expression ◽

Immune Recognition ◽

Antigen Receptors ◽

Class I Mhc ◽

Mhc I

Major histocompatibility class I (MHC-I) proteins mediate immunosurveillance against pathogens and cancers by presenting antigenic or mutated peptides to antigen receptors of CD8+ T cells and by engaging receptors of natural killer (NK) cells. In humans, MHC-I molecules are highly polymorphic. MHC-I variations permit the display of thousands of distinct peptides at the cell surface. Recent mass spectrometric studies have revealed unique and shared characteristics of the peptidomes of individual MHC-I variants. The cell surface expression of MHC-I–peptide complexes requires the functions of many intracellular assembly factors, including the transporter associated with antigen presentation (TAP), tapasin, calreticulin, ERp57, TAP-binding protein related (TAPBPR), endoplasmic reticulum aminopeptidases (ERAPs), and the proteasomes. Recent studies provide important insights into the structural features of these factors that govern MHC-I assembly as well as the mechanisms underlying peptide exchange. Conformational sensing of MHC-I molecules mediates the quality control of intracellular MHC-I assembly and contributes to immune recognition by CD8 at the cell surface. Recent studies also show that several MHC-I variants can follow unconventional assembly routes to the cell surface, conferring selective immune advantages that can be exploited for immunotherapy.

Download Full-text

Lack of effect of mouse adenovirus type 1 infection on cell surface expression of major histocompatibility complex class I antigens.

Journal of Virology ◽

10.1128/jvi.70.8.5495-5502.1996 ◽

1996 ◽

Vol 70 (8) ◽

pp. 5495-5502 ◽

Cited By ~ 12

Author(s):

S C Kring ◽

K R Spindler

Keyword(s):

Major Histocompatibility Complex ◽

Cell Surface ◽

Major Histocompatibility Complex Class ◽

Adenovirus Type ◽

Surface Expression ◽

Class I ◽

Cell Surface Expression ◽

Complex Class ◽

Histocompatibility Complex

Download Full-text

Disrupting Surfaces of Nef Required for Downregulation of CD4 and for Enhancement of Virion Infectivity Attenuates Simian Immunodeficiency Virus Replication In Vivo

Journal of Virology ◽

10.1128/jvi.74.21.9836-9844.2000 ◽

2000 ◽

Vol 74 (21) ◽

pp. 9836-9844 ◽

Cited By ~ 54

Author(s):

A. John Iafrate ◽

Silke Carl ◽

Scott Bronson ◽

Christiane Stahl-Hennig ◽

Tomek Swigut ◽

...

Keyword(s):

Mononuclear Cells ◽

Surface Expression ◽

Class I ◽

Cell Surface Expression ◽

Peripheral Blood Mononuclear ◽

Class I Mhc ◽

Histocompatibility Complex ◽

Immunodeficiency Virus ◽

Selection Of

ABSTRACT The multifunctional simian and human immunodeficiency virus (SIV and HIV) Nef proteins are important for virulence. We studied the importance of selected Nef functions using an SIV Nef with mutations in two regions that are required for CD4 downregulation. This Nef mutant is defective for downregulating CD4 and, in addition, for enhancing SIV infectivity and induction of SIV replication from infected quiescent peripheral blood mononuclear cells, but not for other known functions, including downregulation of class I major histocompatibility complex (MHC) cell surface expression. Replication of SIV containing this Nef variant in rhesus monkeys was attenuated early during infection. Subsequent increases in viral load coincided with selection of reversions and second-site compensatory changes in Nef. Our results indicate that the surfaces of Nef that mediate CD4 downregulation and the enhancement of virion infectivity are critical for SIV replication in vivo. Furthermore, these findings indicate that class I MHC downregulation by Nef is not sufficient for SIV virulence early in infection.

Download Full-text

Ligand Design for Specific MHC Class I Molecules on the Cell Surface

10.26434/chemrxiv.12865688 ◽

2020 ◽

Author(s):

Xizheng Sun ◽

Reika Tokunaga ◽

Yoko Nagai ◽

Ryo Miyahara ◽

Akihiro Kishimura ◽

...

Keyword(s):

Cell Surface ◽

Mhc Class I ◽

Targeted Delivery ◽

Peptide Ligands ◽

Class I ◽

Class I Mhc ◽

Mhc I ◽

Histocompatibility Complex ◽

High Binding Affinity ◽

Mhc Class I Molecules

<p><a></a><a></a><a>We have validated that ligand peptides designed from antigen peptides could be used for targeting specific major histocompatibility complex class I (MHC-I)</a> molecules on cell surface. To design the ligand peptides, we used reported antigen peptides for each MHC-I molecule with high binding affinity. From the crystal structure of the peptide/MHC-I complexes, we determined a modifiable residue in the antigen peptides and replaced this residue with a lysine with an ε-amine group modified with functional molecules. The designed ligand peptides successfully bound to cells expressing the corresponding MHC-I molecules via exchange of peptides bound to the MHC-I. We demonstrated that the peptide ligands could be used to transport a protein or a liposome to cells expressing the corresponding MHC-I. The present strategy may be useful for targeted delivery to cells overexpressing MHC-I, which have been observed autoimmune diseases.</p>

Download Full-text

Faculty Opinions recommendation of Assembly and cell surface expression of TAP-independent, chloroquine-sensitive and interferon-gamma-inducible class I MHC complexes in transformed fibroblast cell lines are regulated by tapasin.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1009214.121258 ◽

2002 ◽

Author(s):

Tim Elliott

Keyword(s):

Cell Surface ◽

Cell Lines ◽

Interferon Gamma ◽

Fibroblast Cell ◽

Surface Expression ◽

Class I ◽

Cell Surface Expression ◽

Class I Mhc ◽

Fibroblast Cell Lines

Download Full-text

Bovine papillomavirus type 1 oncoprotein E5 inhibits equine MHC class I and interacts with equine MHC I heavy chain

Journal of General Virology ◽

10.1099/vir.0.014746-0 ◽

2009 ◽

Vol 90 (12) ◽

pp. 2865-2870 ◽

Cited By ~ 25

Author(s):

Barbara Marchetti ◽

Elisabeth A. Gault ◽

Marc S. Cortese ◽

ZhengQiang Yuan ◽

Shirley A. Ellis ◽

...

Keyword(s):

Heavy Chain ◽

Class I ◽

Bovine Papillomavirus ◽

Class I Mhc ◽

Mhc I ◽

Reading Frame ◽

Histocompatibility Complex ◽

Human Telomerase

Bovine papillomavirus type 1 is one of the aetiological agents of equine sarcoids. The viral major oncoprotein E5 is expressed in virtually all sarcoids, sarcoid cell lines and in vitro-transformed equine fibroblasts. To ascertain whether E5 behaves in equine cells as it does in bovine cells, we introduced the E5 open reading frame into fetal equine fibroblasts (EqPalF). As observed in primary bovine fibroblasts (BoPalF), E5 by itself could not immortalize EqPalF and an immortalizing gene, such as human telomerase (hTERT/hT), was required for the cells to survive selection. The EqPalF-hT-1E5 cells were morphologically transformed, elongated with many pseudopodia and capable of forming foci. Equine major histocompatibility complex class I (MHC I) was inhibited in these cells at least at two levels: transcription of MHC I heavy chain was inhibited and the MHC I complex was retained in the Golgi apparatus and prevented from reaching the cell surface. We conclude that, as in bovine cells and tumours, E5 is a player in the transformation of equine cells and the induction of sarcoids, and a potential major cause of MHC I downregulation and hence poor immune clearance of tumour cells.

Download Full-text

Transmembrane Helices Are an Over-Presented and Evolutionarily Conserved Source of Major Histocompatibility Complex Class I and II Epitopes

Frontiers in Immunology ◽

10.3389/fimmu.2021.763044 ◽

2022 ◽

Vol 12 ◽

Author(s):

Richèl J. C. Bilderbeek ◽

Maksim V. Baranov ◽

Geert van den Bogaart ◽

Frans Bianchi

Keyword(s):

T Cell ◽

Membrane Proteins ◽

T Cell Responses ◽

Class I ◽

Complex Class ◽

Transmembrane Helices ◽

Class I Mhc ◽

Mhc I ◽

Cell Responses ◽

Histocompatibility Complex

Cytolytic T cell responses are predicted to be biased towards membrane proteins. The peptide-binding grooves of most alleles of histocompatibility complex class I (MHC-I) are relatively hydrophobic, therefore peptide fragments derived from human transmembrane helices (TMHs) are predicted to be presented more often as would be expected based on their abundance in the proteome. However, the physiological reason of why membrane proteins might be over-presented is unclear. In this study, we show that the predicted over-presentation of TMH-derived peptides is general, as it is predicted for bacteria and viruses and for both MHC-I and MHC-II, and confirmed by re-analysis of epitope databases. Moreover, we show that TMHs are evolutionarily more conserved, because single nucleotide polymorphisms (SNPs) are present relatively less frequently in TMH-coding chromosomal regions compared to regions coding for extracellular and cytoplasmic protein regions. Thus, our findings suggest that both cytolytic and helper T cells are more tuned to respond to membrane proteins, because these are evolutionary more conserved. We speculate that TMHs are less prone to mutations that enable pathogens to evade T cell responses.

Download Full-text

Novel full-length major histocompatibility complex class I allele discovery and haplotype definition in pig-tailed macaques

10.1101/186494 ◽

2017 ◽

Author(s):

Matthew R. Semler ◽

Roger W. Wiseman ◽

Julie A. Karl ◽

Michael E. Graham ◽

Samantha M. Gieger ◽

...

Keyword(s):

Major Histocompatibility Complex ◽

Full Length ◽

Class I ◽

Major Histocompatibility ◽

Class I Mhc ◽

Mhc I ◽

Pacific Biosciences ◽

Histocompatibility Complex ◽

Immunodeficiency Virus ◽

The Impact

AbstractPig-tailed macaques (Macaca nemestrina, Mane) are important models for human immunodeficiency virus (HIV) studies. Their infectability with minimally modified HIV makes them a uniquely valuable animal model to mimic human infection with HIV and progression to acquired immunodeficiency syndrome (AIDS). However, variation in the pig-tailed macaque major histocompatibility complex (MHC) and the impact of individual transcripts on the pathogenesis of HIV and other infectious diseases is understudied compared to rhesus and cynomolgus macaques. In this study, we used Pacific Biosciences single-molecule real-time circular consensus sequencing to describe full-length MHC class I (MHC-I) transcripts for 194 pig-tailed macaques from three breeding centers. We then used the full-length sequences to inferMane-AandMane-Bhaplotypes containing groups of MHC-I transcripts that co-segregate due to physical linkage. In total, we characterized full-length open reading frames (ORFs) for 313Mane-A,Mane-B, andMane-Isequences that defined 86Mane-Aand 106Mane-BMHC-I haplotypes. Pacific Biosciences technology allows us to resolve theseMane-AandMane-Bhaplotypes to the level of synonymous allelic variants. The newly defined haplotypes and transcript sequences containing full-length ORFs provide an important resource for infectious disease researchers as certain MHC haplotypes have been shown to provide exceptional control of simian immunodeficiency virus (SIV) replication and prevention of AIDS-like disease in nonhuman primates. The increased allelic resolution provided by Pacific Biosciences sequencing also benefits transplant research by allowing researchers to more specifically match haplotypes between donors and recipients to the level of nonsynonymous allelic variation, thus reducing the risk of graft-versus-host disease.

Download Full-text