ITGAL encodes the integrin alpha L chain. Integrins are heterodimeric integral membrane proteins composed of an alpha chain and a beta chain. This I-domain containing alpha integrin combines with the beta 2 chain (ITGB2) to form the integrin lymphocyte function-associated antigen-1 (LFA-1)，which is expressed on all leukocytes. LFA-1 plays a central role in leukocyte intercellular adhesion through interactions with its ligands，ICAMs 1-3(intercellular adhesion molecules 1 through 3)，and also functions in lymphocyte costimulatory signaling. Two transcript variants encoding different isoforms have been found for this gene.