Search results for "Peptide binding"

Skeletal Dysplasia Mutations Effect on Human Filamins’ Structure and Mechanosensing

2016

AbstractCells’ ability to sense mechanical cues in their environment is crucial for fundamental cellular processes, leading defects in mechanosensing to be linked to many diseases. The actin cross-linking protein Filamin has an important role in the conversion of mechanical forces into biochemical signals. Here, we reveal how mutations in Filamin genes known to cause Larsen syndrome and Frontometaphyseal dysplasia can affect the structure and therefore function of Filamin domains 16 and 17. Employing X-ray crystallography, the structure of these domains was first solved for the human Filamin B. The interaction seen between domains 16 and 17 is broken by shear force as revealed by steered mo…

Amino Acid Polymorphisms in Hla Class II Differentiate Between Thyroid and Polyglandular Autoimmunity.

2019

Abstract Context The structure of the human leucocyte antigen (HLA) peptide-binding clefts strongly contributes to monoglandular and polyglandular autoimmunity (AP). Objective To investigate the impact of amino acid polymorphisms on the peptide-binding interactions within HLA class II and its association with AP. Design Immunogenetic study. Setting Tertiary referral center for autoimmune endocrine diseases. Subjects 587 subjects with AP, autoimmune thyroid disease (AITD), type 1 diabetes (T1D), and healthy unrelated controls were typed for HLA class II. Methods Amino acids within the peptide binding cleft that are encoded by HLA class II exon 2 were listed for all codon positions in all sub…

Positive Role of the MHC Class-I Antigen Presentation Regulator m04/gp34 of Murine Cytomegalovirus in Antiviral Protection by CD8 T Cells

2020

Murine cytomegalovirus (mCMV) codes for MHC class-I trafficking modulators m04/gp34, m06/gp48, and m152/gp40. By interacting with the MHC class-Iα chain, these proteins disconnect peptide-loaded MHC class-I (pMHC-I) complexes from the constitutive vesicular flow to the cell surface. Based on the assumption that all three inhibit antigen presentation, and thus the recognition of infected cells by CD8 T cells, they were referred to as “immunoevasins.” Improved antigen presentation mediated by m04 in the presence of m152 after infection with deletion mutant mCMV-Δm06W, compared to mCMV-Δm04m06 expressing only m152, led us to propose renaming these molecules “viral regulators of antigen present…

2018

The cellular inhibitor of apoptosis 1 (cIAP1) is an E3-ubiquitin ligase that regulates cell signaling pathways involved in fundamental cellular processes including cell death, cell proliferation, cell differentiation and inflammation. It recruits ubiquitination substrates thanks to the presence of three baculoviral IAP repeat (BIR) domains at its N-terminal extremity. We previously demonstrated that cIAP1 promoted the ubiquitination of the E2 factor 1 (E2F1) transcription factor. Moreover, we showed that cIAP1 was required for E2F1 stabilization during the S phase of cell cycle and in response to DNA damage. Here, we report that E2F1 binds within the cIAP1 BIR3 domain. The BIR3 contains a s…

Mortality in COVID-19 disease patients: Correlating Association of Major histocompatibility complex (MHC) with severe acute respiratory syndrome 2 (S…

2020

Highlights • In addition to ethnicity, socio-economic factors, prior vaccinations and exposure to other coronaviruses, other factors need to be considered to explain geographical and regional variations in susceptibility, severity of clinical expression of COVID-19 disease and outcomes. • Differences in peptide binding of SARS-CoV-2 variants to MHC class II, but not to MHC class I alleles frequent in individuals with African, Asian or Caucasian descent could be identified. • Single mutations in the wildtype of SARS-CoV-2, the so called B strain or L strain impact on MHC presentation • Most likely there is selective pressure from MHC class II alleles in regard to binding of the ORF8 (L84S) v…

Hepatitis B surface antigen presentation and HLA-DRB1*– lessons from twins and peptide binding studies

2005

Summary The aim of this study was to investigate the underlying mechanisms of the genetic association between certain HLA-DRB1* alleles and the immune response to HBsAg vaccination. Therefore, HBsAg peptide binding to HLA-DR molecules was measured in vitro by peptide binding ELISAs. Additionally, HBsAg-specific T cell reaction and cytokine profile of immune response were analysed ex vivo in ELISPOT assays and DR-restriction of T-cell proliferative responses was investigated with HBsAg specific T cell clones. In addition, we compared HBsAg specific T cell responses of 24 monozygotic and 3 dizygotic twin pairs after HBsAg vaccination. Our results showed that the peptide binding assays did not…

Amino acid substitutions at position 97 in HLA-A2 segregate cytolysis from cytokine release in MART-1/Melan-A peptide AAGIGILTV-specific cytotoxic T …

1996

CD8+ T lymphocytes recognize antigenic peptides presented by major histocompatibility complex (MHC) class I molecules. Individual peptide termini appear to be fixed at the C- and N-terminal ends. In contrast, central peptide side chains residues may point in different directions and exhibit limited flexibility, dependent on the MHC class I structural variation. For instance, position 97 in HLA-A201 has been shown to shift individual peptide species into different coordinations, one oriented towards the peptide N terminus, or more towards the C-terminal end. The conformational shape of such non-anchor peptide residues may affect the affinity of MHC/peptide/TCR interaction, resulting in quant…

Isolation of Mhc class I cDNAs from the axolotl Ambystoma mexicanum.

1997

Class I major histocompatibility complex (Mhc) cDNA clones were isolated from axolotl mRNA by polymerase chain reaction (PCR) and by screening a cDNA phage library. The nucleotide and predicted amino acid sequences show definite similarities to the Mhc class Ialpha molecules of higher vertebrates. Most of the amino acids in the peptide binding region that dock peptides at their N and C termini in mammals are conserved. Several amino acids considered to be important for the interaction of beta2-microglobulin with the Mhc alpha chain are also conserved in the axolotl sequence. The fact that axolotl class I A cDNAs are ubiquitously expressed and highly polymorphic in the alpha1 and alpha2 doma…

Structure of MHC class I and class II cDNAs and possible immunodeficiency linked to class II expression in the Mexican axolotl

1998

Despite the fact that the axolotl (Ambystoma spp. a urodele amphibian) displays a large T-cell repertoire and a reasonable B-cell repertoire, its humoral immune response is slow (60 days), non-anamnestic, with a unique IgM class. The cytotoxic immune response is slow as well (21 days) with poor mixed lymphocyte reaction stimulation. Therefore, this amphibian can be considered as immunodeficient. The reason for this subdued immune response could be an altered antigenic presentation by major histocompatibility complex (MHC) molecules. This article summarizes our work on axolotl MHC genes. Class I genes have been characterized and the cDNA sequences show a good conservation of non-polymorphic …

Axolotl MHC class II β chain: predominance of one allele and alternative splicing of the β1 domain

2001

The axolotl MHC is composed of multiple polymorphic class I loci linked to class II B loci. In this report, evidence of the existence of one class II B locus (Amme-DAB) that codes for two different transcripts is given. A 2.1-kb transcript is translated to a complete β chain and a shorter transcript of 1.8 kb encodes a molecule lacking the β1 domain. For two complete class II B mRNA synthesized, up to one mRNA devoid of the β1 domain is synthesized. Alternative splicing involving a peptide binding domain at a class II B locus evidenced in axolotl (Ambystoma mexicanum) is also observed for A. trigrinum, the tiger salamander. Very little variability is found among various axolotl MHC class II…