The ITGB2 protein product is the integrin beta chain beta 2. Integrins are integral cell-surface proteins composed of an alpha chain and a beta chain. A given chain may combine with multiple partners resulting in different integrins. For example, beta 2 combines with the alpha L chain to form the integrin LFA-1, and combines with the alpha M chain to form the integrin Mac-1. Integrins are known to participate in cell adhesion as well as cell-surface mediated signalling.
In humans lack of CD18 causes Leukocyte Adhesion Deficiency, a disease defined by a lack of leukocyte extravasation from blood into tissues. The beta 2 integrins have also been found in a soluble form. The soluble beta 2 integrins are ligand binding and plasma levels are inversely associated with disease activity in the autoimmune disease spondyloarthritis.
↑Gjelstrup, L. C.; Boesen, T.; Kragstrup, T. W.; Jorgensen, A.; Klein, N. J.; Thiel, S.; Deleuran, B. W.; Vorup-Jensen, T. (8 September 2010). "Shedding of Large Functionally Active CD11/CD18 Integrin Complexes from Leukocyte Membranes during Synovial Inflammation Distinguishes Three Types of Arthritis through Differential Epitope Exposure". The Journal of Immunology. 185 (7): 4154–4168. doi:10.4049/jimmunol.1000952.
↑Kragstrup, Tue W; Jalilian, Babak; Hvid, Malene; Kjærgaard, Anders; Østgård, René; Schiøttz-Christensen, Berit; Jurik, Anne G; Robinson, William H; Vorup-Jensen, Thomas; Deleuran, Bent (2014). "Decreased plasma levels of soluble CD18 link leukocyte infiltration with disease activity in spondyloarthritis". Arthritis Research & Therapy. 16 (1): R42. doi:10.1186/ar4471.
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↑Liliental J, Chang DD (Jan 1998). "Rack1, a receptor for activated protein kinase C, interacts with integrin beta subunit". The Journal of Biological Chemistry. 273 (4): 2379–83. doi:10.1074/jbc.273.4.2379. PMID9442085.
↑Kotovuori A, Pessa-Morikawa T, Kotovuori P, Nortamo P, Gahmberg CG (June 1999). "ICAM-2 and a peptide from its binding domain are efficient activators of leukocyte adhesion and integrin affinity". Journal of Immunology. 162 (11): 6613–20. PMID10352278.
↑Lu C, Takagi J, Springer TA (May 2001). "Association of the membrane proximal regions of the alpha and beta subunit cytoplasmic domains constrains an integrin in the inactive state". The Journal of Biological Chemistry. 276 (18): 14642–8. doi:10.1074/jbc.M100600200. PMID11279101.
↑Huang C, Springer TA (August 1995). "A binding interface on the I domain of lymphocyte function-associated antigen-1 (LFA-1) required for specific interaction with intercellular adhesion molecule 1 (ICAM-1)". The Journal of Biological Chemistry. 270 (32): 19008–16. doi:10.1074/jbc.270.32.19008. PMID7642561.
↑Rietzler M, Bittner M, Kolanus W, Schuster A, Holzmann B (October 1998). "The human WD repeat protein WAIT-1 specifically interacts with the cytoplasmic tails of beta7-integrins". The Journal of Biological Chemistry. 273 (42): 27459–66. doi:10.1074/jbc.273.42.27459. PMID9765275.