The Core Cysteines, (C909) of Islet Antigen-2 and (C945) of Islet Antigen-2β, Are Crucial to Autoantibody Binding in Type 1 Diabetes
| العنوان: | The Core Cysteines, (C909) of Islet Antigen-2 and (C945) of Islet Antigen-2β, Are Crucial to Autoantibody Binding in Type 1 Diabetes |
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| المؤلفون: | Polly J. Bingley, Karen T Elvers, Deborah K. Shoemark, Ivey A. Geoghegan, Vito Lampasona, Alistair J K Williams |
| المصدر: | Diabetes |
| بيانات النشر: | American Diabetes Association, 2012. |
| سنة النشر: | 2012 |
| مصطلحات موضوعية: | Adult, Male, Adolescent, Endocrinology, Diabetes and Metabolism, Molecular Sequence Data, 030209 endocrinology & metabolism, Protein tyrosine phosphatase, Biology, Epitope, Structure-Activity Relationship, 03 medical and health sciences, 0302 clinical medicine, Protein structure, Internal Medicine, Humans, Receptor-Like Protein Tyrosine Phosphatases, Class 8, Amino Acid Sequence, Cysteine, Child, Autoantibodies, 030304 developmental biology, 0303 health sciences, Autoantibody, Antibodies, Monoclonal, Molecular biology, Protein Structure, Tertiary, 3. Good health, Diabetes Mellitus, Type 1, Epitope mapping, Biochemistry, Child, Preschool, Female, Radiobinding assay, Immunology and Transplantation, Epitope Mapping, Conformational epitope |
| الوصف: | Cysteines are thought integral to conformational epitopes of islet antigen-2 (IA-2) autoantibodies (IA-2A), possibly through disulfide bond formation. We therefore investigated which cysteines are critical to IA-2A binding in patients with newly diagnosed type 1 diabetes. All 10 cysteines in the intracellular domain of IA-2 were modified to serine by site-directed mutagenesis, and the effects of these changes on autoantibody binding in comparison with wild-type control were investigated by radiobinding assay. Mutation of the protein tyrosine phosphatase (PTP) core cysteine (C909) in IA-2 caused large reductions in autoantibody binding. In contrast, little or no reduction in binding was seen following substitution of the other cysteines. Modification of the core cysteine (C945) in IA-2β also greatly reduced autoantibody binding. Lysine substitution of glutamate-836 in IA-2 or glutamate-872 in IA-2β resulted in modest reductions in binding and identified a second epitope region. Binding to IA-2 PTP and IA-2β PTP was almost abolished by mutation of both the core cysteine and these glutamates. The core cysteine is key to the major PTP conformational epitope, but disulfide bonding contributes little to IA-2A epitope integrity. In most patients, at disease onset, >90% of antibodies binding to the PTP domain of IA-2 recognize just two epitope regions. |
| تدمد: | 1939-327X 0012-1797 |
| الوصول الحر: | https://explore.openaire.eu/search/publication?articleId=doi_dedup___::7e2407457a3072b0aa6c8ac3c3fb527bTest https://doi.org/10.2337/db11-1590Test |
| حقوق: | OPEN |
| رقم الانضمام: | edsair.doi.dedup.....7e2407457a3072b0aa6c8ac3c3fb527b |
| قاعدة البيانات: | OpenAIRE |
| تدمد: | 1939327X 00121797 |
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