CD11b
CD11b (integrin subunit alpha M, ITGAM) is the alpha chain of a leukocyte-specific integrin that pairs with ITGB2/CD18. Also known as MAC-1, CR3A and HNA-4, it mediates adhesion of myeloid cells and uptake of complement-coated particles. Browse Assay Genie's current range of CD11b research reagents below, or read on for the biology behind the target.
CD11b is the alpha M chain of the ITGAM/ITGB2 integrin, a heterodimeric integral membrane protein made up of an alpha chain and a beta chain. This I-domain containing alpha integrin combines with the beta 2 chain (ITGB2, or CD18) to form the leukocyte-specific receptor known as macrophage receptor 1 (Mac-1) or inactivated-C3b (iC3b) receptor 3 (CR3). The complex is implicated in adhesive interactions of monocytes, macrophages and granulocytes, and in mediating the uptake of complement-coated particles and pathogens.
As CR-3, the integrin is the receptor for the iC3b fragment of the third complement component, and it probably recognises the R-G-D peptide in C3b. It also acts as a receptor for fibrinogen, recognising the P1 and P2 peptides of the fibrinogen gamma chain, and for factor X. As a receptor for ICAM1, it ensures adhesion between stimulated neutrophils and stimulated endothelial cells. CD11b regulates neutrophil migration and, with ITGB2/CD18, is required for CD177-PRTN3-mediated activation of TNF-primed neutrophils. It may also regulate phagocytosis-induced apoptosis in extravasated neutrophils and may play a role in mast cell development. In microglia, it is required with TYROBP/DAP12 to control production of superoxide ions, which promote the neuronal apoptosis that occurs during brain development.
The CD11b gene, officially ITGAM, encodes a protein of the integrin alpha chain family, and multiple transcript variants encoding different isoforms have been described. HGNC classes it among CD molecules, integrin alpha subunits, complement system regulators and receptors, and human neutrophil antigens. Earlier gene names described it as the complement component receptor 3 alpha chain and macrophage antigen alpha polypeptide. The mouse ortholog is Itgam.
CD11b is important in the adherence of neutrophils and monocytes to stimulated endothelium, making it a core subject in leukocyte adhesion and migration studies.
As the iC3b receptor CR3, CD11b mediates uptake of complement-coated particles and pathogens, supporting work on complement-driven phagocytosis.
With ITGB2/CD18, CD11b is required for CD177-PRTN3-mediated activation of TNF-primed neutrophils and regulates neutrophil migration.
CD11b acts with TYROBP/DAP12 in microglia to control superoxide production that promotes neuronal apoptosis during brain development.
CD11b is the alpha subunit of the ITGAM/ITGB2 integrin. It mediates adhesion of monocytes, macrophages and granulocytes, binds iC3b, fibrinogen, factor X and ICAM1, and supports uptake of complement-coated particles and pathogens. It also regulates neutrophil migration.
The gene symbol is ITGAM. Aliases include MAC-1, CR3A, HNA-4 and CD11B. The ITGAM/ITGB2 complex is called Mac-1 or complement receptor 3 (CR3). Multiple transcript variants encoding different isoforms have been reported.
The mouse ortholog of human CD11b is Itgam. The protein belongs to the integrin alpha chain family. Check the datasheet of any product for its validated reactivity.
Integrin partners, complement components and neutrophil and microglial signalling proteins linked to CD11b.
Gene and protein annotations from HGNC, NCBI Gene and UniProt P11215; product specifications from Assay Genie datasheets.