Integrin beta 7

Integrin beta 7 is a protein that in humans is encoded by the ITGB7 gene. Integrins are a family of cell adhesion molecules that are integral to a wide range of cellular processes including immunological responses, wound healing, and cancer metastasis. They are heterodimeric proteins, consisting of an alpha and a beta chain, that mediate adhesion of cells to the extracellular matrix (ECM) and to other cells. Integrin beta 7 partners with integrin alpha 4 (encoded by the ITGA4 gene) to form the lymphocyte Peyer's patch adhesion molecule (LPAM-1), and with integrin alpha E (encoded by the ITGAE gene) to form the mucosal lymphocyte integrin molecule (αEβ7), which is important for lymphocyte migration and retention in gut-associated lymphoid tissues (GALT).

Function

Integrin beta 7 plays a crucial role in the immune system, particularly in the function and regulation of T cells and B cells within the gastrointestinal tract. By mediating the adhesion of lymphocytes to the intestinal epithelium, it facilitates the surveillance of the intestinal mucosa for pathogens and contributes to the maintenance of intestinal homeostasis. This integrin is also involved in the pathogenesis of several inflammatory diseases, including inflammatory bowel disease (IBD) and celiac disease, due to its role in mediating lymphocyte migration to inflamed tissues.

Structure

The ITGB7 gene encodes the beta 7 subunit of integrin, which non-covalently associates with specific alpha subunits to form functional adhesion molecules. The structure of integrin beta 7, like other integrin beta subunits, includes a large extracellular domain, a single transmembrane domain, and a short cytoplasmic tail. The extracellular domain is responsible for binding to the ECM or to other cells, while the cytoplasmic tail interacts with intracellular proteins that mediate signal transduction pathways.

Clinical Significance

Given its role in mediating immune responses in the gut, integrin beta 7 has been a target for therapeutic intervention in diseases such as IBD. Drugs that block the interaction of α4β7 integrin with its ligands have shown promise in reducing inflammation and promoting mucosal healing in patients with IBD. However, targeting integrin beta 7 must be approached with caution, as disrupting normal immune surveillance in the gut could potentially lead to increased susceptibility to infections or the development of tumors.

Genetics

The ITGB7 gene is located on human chromosome 12, and mutations in this gene have been associated with various immunological disorders. Research into the genetic regulation of ITGB7 expression and its polymorphisms may provide further insights into its role in disease and potential as a therapeutic target.