Immunity; T cell controls (Introduction)

by David Turell , Tuesday, April 12, 2016, 19:24 (3148 days ago) @ David Turell

Lymphocyte cells (T cells) are very important in the immune processes as they are attack cells and there are molecular controls over their activity:-https://www.sciencedaily.com/releases/2016/04/160412090718.htm-"The protein MALT1 is an important switch in immune cells and affects their activity. Researchers at Helmholtz Zentrum München report in 'Nature Communications' that this activation is not always equally strong. Through alternative splicing, two variants of the protein may arise which have a stronger or weaker effect on the immune system. Understanding this process is important for the pharmacological use of MALT1.-"The protein MALT1 (mucosa-associated lymphoid tissue lymphoma translocation protein 1) controls the activation of lymphocytes and thus the immune response following bacterial or viral infections. For this purpose, the protease cleaves other proteins in the cell and is considered a potential target for the treatment of excessive immune responses as observed in autoimmune diseases (e.g. multiple sclerosis) or distinct malignant lymphomas.-***-"To our surprise, we showed that MALT1 is regulated by posttranscriptional splicing," said first author Isabel Meininger, a doctoral student at Helmholtz Zentrum München. "Depending on which MALT1 variant is expressed, the immune system activated is more or less," she added.-"Specifically, the scientists observed that MALT1A resulted in a stronger stimulation of T cells than MALT1B. According to the study, a molecule called hnRNP U (heterogeneous nuclear ribonucleoprotein U) regulates which of the two isoforms is preferably expressed. If it is present in only small amounts, higher levels of MALT1A are expressed, resulting in stronger activation of the T cells. However, if the quantity of hnRNP U is increased, higher levels of MALT1B are expressed and the response of the T cells is weaker."-***-" Alternative splicing refers to a process in which a copy of a gene, the pre-mRNA, is spliced differently. Thus, several alternative RNA sequences can be generated that as a consequence lead to different proteins. In the case of MALT1 the variants A and B differ only through the presence of a short sequence that encodes eleven amino acids. If this region is missing, as in the case of MALT1B, this leads to an impaired ability to stimulate T cells."-Comment: Just to show the complexity of how the immune system is modulated in the degree of its responsiveness. Note the role of the genome in this modulation.