Integrin alpha 4

Integrin alpha 4 (ITGA4) is a protein that in humans is encoded by the ITGA4 gene. Integrin alpha 4 is a type of integrin, a family of cell adhesion molecules that are integral to a variety of cellular processes including embryogenesis, hemostasis, tissue repair, immune response, and metastatic spread of tumor cells.

Structure

Integrin alpha 4 forms a heterodimer with beta 1 integrin (also known as CD29) or beta 7 integrin. The alpha 4 chain contains a peptide sequence that is critical for its binding to fibronectin, VCAM-1 (vascular cell adhesion molecule-1), and MAdCAM-1 (mucosal addressin cell adhesion molecule-1). This interaction is essential for the adhesion of leukocytes to the endothelium and for their migration to sites of inflammation.

Function

The primary role of integrin alpha 4 is to mediate cell adhesion and migration. It is prominently involved in the regulation of leukocyte trafficking and positioning within tissues, particularly in the context of inflammation and immune response. Integrin alpha 4 is also implicated in the pathogenesis of several diseases, including autoimmune diseases, allergic reactions, and cancer. In autoimmune diseases, for example, the aberrant trafficking of leukocytes mediated by integrin alpha 4 contributes to tissue damage and disease progression.

Clinical Significance

Given its role in mediating leukocyte adhesion and migration, integrin alpha 4 has been a target for therapeutic intervention in various diseases. Natalizumab, a monoclonal antibody that targets integrin alpha 4, has been approved for the treatment of multiple sclerosis and Crohn's disease. By blocking the interaction of integrin alpha 4 with its ligands, natalizumab prevents the migration of leukocytes across the endothelium into inflamed tissue, thereby reducing inflammation and tissue damage.

Research

Research on integrin alpha 4 continues to uncover its complex roles in health and disease. Studies are exploring its involvement in the regulation of the immune system, its potential as a target for cancer therapy, and its role in other diseases characterized by abnormal cell adhesion and migration.