Integrin alpha subunit (ITGA) (ITGA)

Integrin alpha subunits are a family of 18 distinct type I transmembrane proteins that non-covalently pair with one of eight beta subunits to form functional heterodimeric integrin receptors [1, 10, 14]. These receptors serve as critical mechanical and chemical links between the extracellular matrix (ECM) and the intracellular cytoskeleton, facilitating bidirectional signaling known as inside-out and outside-in signaling [10, 13, 15]. Through these pathways, integrin alpha subunits regulate essential cellular processes including adhesion, migration, proliferation, and survival [3, 18]. In pathological contexts, they are heavily involved in cancer metastasis, tumor angiogenesis, chronic inflammatory diseases, and thrombotic disorders [3, 4, 6, 15]. Consequently, they have become major therapeutic targets; for instance, drugs like natalizumab target the alpha-4 subunit to treat multiple sclerosis, while others like tirofiban target the alpha-IIb subunit to prevent coronary thrombosis [10, 16]. Despite their therapeutic success, targeting integrin alpha subunits presents challenges such as the risk of progressive multifocal leukoencephalopathy or significant bleeding, depending on the specific subunit inhibited [10].

Other names

ITGACD antigenVery late antigen subunitVLA subunitAdhesion receptor alpha subunitCD11aCD11bCD11cCD49aCD49bCD49cCD49dCD49eCD49fCD51CD103CD150ITGAVITGA4ITGA2B

Integrin alpha subunits act as the primary ligand-binding components of integrin heterodimers. Therapeutic agents typically function as antagonists that bind to the extracellular domains (such as the I-domain or the RGD-binding pocket) to block interactions with ligands like fibronectin, VCAM-1, or ICAM-1. This inhibition prevents the outside-in signaling required for cell adhesion, migration, and activation, thereby modulating immune responses, preventing thrombosis, or inhibiting tumor progression.