scholarly journals Activation of Stat-3 Is Involved in the Induction of Apoptosis After Ligation of Major Histocompatibility Complex Class I Molecules on Human Jurkat T Cells

Blood ◽  
1998 ◽  
Vol 91 (10) ◽  
pp. 3566-3573 ◽  
Author(s):  
Søren Skov ◽  
Mette Nielsen ◽  
Søren Bregenholt ◽  
Niels Ødum ◽  
Mogens H. Claesson

Abstract Activation of Janus tyrosine kinases (Jak) and Signal transducers and activators of transcription (Stat) after ligation of major histocompatibility complex class I (MHC-I) was explored in Jurkat T cells. Cross-linking of MHC-I mediated tyrosine phosphorylation of Tyk2, but not Jak1, Jak2, and Jak3. In addition, the transcription factor Stat-3 was tyrosine phosphorylated in the cytoplasma and subsequently translocated to the cell nucleus. Data obtained by electrophoretic mobility shift assay suggested that the activated Stat-3 protein associates with the human serum-inducible element (hSIE) DNA-probe derived from the interferon-γ activated site (GAS) in the c-fos promoter, a common DNA sequence for Stat protein binding. An association between hSIE and Stat-3 after MHC-I ligation was directly demonstrated by precipitating Stat-3 from nuclear extracts with biotinylated hSIE probe and avidin-coupled agarose. To investigate the function of the activated Stat-3, Jurkat T cells were transiently transfected with a Stat-3 isoform lacking the transactivating domain. This dominant-negative acting Stat-3 isoform significantly inhibited apoptosis induced by ligation of MHC-I. In conclusion, our data suggest the involvement of the Jak/Stat signal pathway in MHC-I–induced signal transduction in T cells.

Blood ◽  
1998 ◽  
Vol 91 (10) ◽  
pp. 3566-3573
Author(s):  
Søren Skov ◽  
Mette Nielsen ◽  
Søren Bregenholt ◽  
Niels Ødum ◽  
Mogens H. Claesson

Activation of Janus tyrosine kinases (Jak) and Signal transducers and activators of transcription (Stat) after ligation of major histocompatibility complex class I (MHC-I) was explored in Jurkat T cells. Cross-linking of MHC-I mediated tyrosine phosphorylation of Tyk2, but not Jak1, Jak2, and Jak3. In addition, the transcription factor Stat-3 was tyrosine phosphorylated in the cytoplasma and subsequently translocated to the cell nucleus. Data obtained by electrophoretic mobility shift assay suggested that the activated Stat-3 protein associates with the human serum-inducible element (hSIE) DNA-probe derived from the interferon-γ activated site (GAS) in the c-fos promoter, a common DNA sequence for Stat protein binding. An association between hSIE and Stat-3 after MHC-I ligation was directly demonstrated by precipitating Stat-3 from nuclear extracts with biotinylated hSIE probe and avidin-coupled agarose. To investigate the function of the activated Stat-3, Jurkat T cells were transiently transfected with a Stat-3 isoform lacking the transactivating domain. This dominant-negative acting Stat-3 isoform significantly inhibited apoptosis induced by ligation of MHC-I. In conclusion, our data suggest the involvement of the Jak/Stat signal pathway in MHC-I–induced signal transduction in T cells.


2012 ◽  
Vol 513 (2) ◽  
pp. 223-228 ◽  
Author(s):  
Rodrigo Fabrizzio Inácio ◽  
Renata Graciele Zanon ◽  
Liana Verinaud ◽  
Alexandre Leite Rodrigues de Oliveira

2013 ◽  
Vol 288 (45) ◽  
pp. 32797-32808 ◽  
Author(s):  
Andy van Hateren ◽  
Rachel Carter ◽  
Alistair Bailey ◽  
Nasia Kontouli ◽  
Anthony P. Williams ◽  
...  

2000 ◽  
Vol 74 (19) ◽  
pp. 9256-9266 ◽  
Author(s):  
Sylvie Le Gall ◽  
Florence Buseyne ◽  
Alicja Trocha ◽  
Bruce D. Walker ◽  
Jean-Michel Heard ◽  
...  

ABSTRACT The human immunodeficiency virus type 1 Nef protein alters the post-Golgi stages of major histocompatibility complex class I (MHC-I) biogenesis. Presumed mechanisms involve the disclosure of a cryptic tyrosine-based sorting signal (YSQA) located in the cytoplasmic tail of HLA-A and -B heavy chains. We changed this signal for a prototypic sorting motif (YSQI or YSQL). Modified HLA-A2 molecules, termed A2-endo, displayed constitutively low surface levels and accumulated in a region close to or within the Golgi apparatus, a behavior reminiscent of wild-type HLA-A2 in Nef-expressing cells. However, several lines of evidence indicate that the action of prototypic signals on MHC-I trafficking differs from that of Nef. Internalization of surface A2-endo was more rapid and was associated with efficient recycling to the surface. A transdominant-negative mutant of dynamin-1 inhibited A2-endo constitutive internalization and Nef-induced CD4 down-regulation, whereas it did not affect the activity of Nef on MHC-I. Moreover, trafficking of A2-endo was still affected by the viral protein, indicating additive effects of prototypic signals and Nef. Therefore, distinct trafficking pathways regulate clathrin-dependent and Nef-induced MHC-I modulation.


2010 ◽  
Vol 84 (10) ◽  
pp. 5443-5447 ◽  
Author(s):  
Thomas C. Friedrich ◽  
Shari M. Piaskowski ◽  
Enrique J. León ◽  
Jessica R. Furlott ◽  
Nicholas J. Maness ◽  
...  

ABSTRACT Human and simian immunodeficiency viruses (HIV and SIV) downregulate major histocompatibility complex class I (MHC-I) molecules from the surface of infected cells. Although this activity is conserved across viral isolates, its importance in AIDS pathogenesis is not clear. We therefore developed an assay to detect the level of MHC-I expression of SIV-infected cells directly ex vivo. Here we show that the extent of MHC-I downregulation is greatest in SIVmac239-infected macaques that never effectively control virus replication. Our results suggest that a high level of MHC-I downregulation is a hallmark of fast disease progression in SIV infection.


2002 ◽  
Vol 76 (2) ◽  
pp. 633-643 ◽  
Author(s):  
Kathy Triantafilou ◽  
Didier Fradelizi ◽  
Keith Wilson ◽  
Martha Triantafilou

ABSTRACT It is becoming apparent that over the years cell infection by virus seems to have evolved into a multistep process in which many viruses employ distinct cell surface molecules for their attachment and cell entry. In this study the attachment and entry pathway of coxsackievirus A9 (CAV-9), a member of the Picornaviridae family, was investigated. It has been known that, although integrin αvβ3 is utilized as a receptor, its presence alone is insufficient for CAV-9 infection and that CAV-9 also requires a 70-kDa major histocompatibility complex class I (MHC-I)-associated protein (MAP-70) as a coreceptor molecule. We document by protein isolation and peptide sequencing that the 70-kDa protein is GRP78, a member of the heat shock protein 70 family of stress proteins. Furthermore we show by using fluorescence resonance energy transfer (FRET) that GRP78 is also expressed on the cell surface and associates with MHC-I molecules. In addition CAV-9 infection of permissive cells requires GRP78 and also MHC-I molecules, which are essential for virus internalization. The identification of GRP78 as a coreceptor for CAV-9 and the revelation of GRP78 and MHC-I associations have provided new insights into the life cycle of CAV-9, which utilizes integrin αvβ3 and GRP78 as receptor molecules whereas MHC-I molecules serve as the internalization pathway of this virus to mammalian cells.


2020 ◽  
Author(s):  
Yuan Feng ◽  
William H. Hildebrand ◽  
Stephen M. Tompkins ◽  
Shaying Zhao

AbstractThe major histocompatibility complex class I (MHC-I) genes are highly polymorphic among individuals. MHC-I genotyping is required for determining the antigen-binding specificity of each MHC-I molecule in an individual. Numerous tools have been developed for human MHC-I genotyping using deep sequencing data such as RNA-seq; however they do not work for the dog, due to very limited information for canine alleles. To address this issue, we developed a Kmer-based paired-end read (KPR) de novo assembler and genotyper, which first assemble paired-end RNA-seq reads mapped to the MHC-I regions into contigs de novo and then genotype each contig. Our KPR tools are validated by Sanger sequencing, simulation and published genotype data. Applying our KPR tools on the published RNA-seq data of 158 tumor and 64 normal samples from 158 dogs, we have achieved a genotyping success rate of 86%, which includes 133 tumor and 57 normal samples from 142 dogs. We have identified 39 known alleles and 83 new alleles of high confidence in these dogs, yielding a more comprehensive MHC-I allele diversity landscape for the dog.


2015 ◽  
Vol 90 (4) ◽  
pp. 2119-2126 ◽  
Author(s):  
Andrea M. Weiler ◽  
Arpita Das ◽  
Oluwasayo Akinyosoye ◽  
Sherry Cui ◽  
Shelby L. O'Connor ◽  
...  

Nef-specific CD8+T lymphocytes (CD8TL) are associated with control of simian immunodeficiency virus (SIV) despite extensivenefvariation between and within animals. Deep viral sequencing of the immunodominant Mamu-B*017:01-restricted Nef165–173IW9 epitope revealed highly restricted evolution. A common acute escape variant, T170I, unexpectedly and uniquely degraded Nef's major histocompatibility complex class I (MHC-I) downregulatory capacity, rendering the virus more vulnerable to CD8TL targeting other epitopes. These data aid in a mechanistic understanding of Nef functions and suggest means of immunity-mediated control of lentivirus replication.


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