Integrin alpha M

Integrin alpha M (ITGAM) is one protein subunit that forms <a href="/facts/Heterodimer/c8LwFJPG">heterodimeric</a> <a href="/facts/Integrin/DNYUGbBp">integrin</a> alpha-M beta-2 (αMβ2) molecule, also known as <a href="/facts/Macrophage-1_antigen/ft7kK5a7">macrophage-1 antigen</a> (Mac-1) or <a href="/facts/Complement_receptor/EsI570Ic">complement receptor</a> 3 (CR3). ITGAM is also known as CR3A, and <a href="/facts/Cluster_of_differentiation/cLEuDQId">cluster of differentiation</a> molecule 11B (CD11B). The second chain of αMβ2 is the common integrin β2 subunit known as <a href="/facts/CD18/gCr14tJd">CD18</a>, and integrin αMβ2 thus belongs to the β2 subfamily (or leukocyte) integrins.
αMβ2 is expressed on the surface of many <a href="/facts/Leukocyte/vsDunUK0">leukocytes</a> involved in the <a href="/facts/Innate_immune_system/lz4BpSQI">innate immune system</a>, including <a href="/facts/Monocyte/FW4NNMKM">monocytes</a>, <a href="/facts/Granulocyte/zsE3ldLb">granulocytes</a>, <a href="/facts/Macrophage/z7hkQu3o">macrophages</a>, and <a href="/facts/Natural_killer_cell/A3THWxrJ">natural killer cells</a> and subsets of T and B cells. It mediates inflammation by regulating leukocyte <a href="/facts/Cell_adhesion/Vg4alzxb">adhesion</a> and migration and has been implicated in several immune processes such as <a href="/facts/Phagocytosis/eBrv2XKV">phagocytosis</a>, cell-mediated cytotoxicity, <a href="/facts/Chemotaxis/hYPRdPTk">chemotaxis</a> and cellular activation. It is involved in the <a href="/facts/Complement_system/vRSrQDUv">complement system</a> due to its capacity to bind inactivated <a href="/facts/Complement_component_3b/pqsRthBP">complement component 3b</a> (iC3b). The ITGAM (alpha) subunit of integrin αMβ2 is directly involved in causing the adhesion and spreading of cells but cannot mediate cellular migration without the presence of the β2 (CD18) subunit.
In genomewide association studies, single nucleotide polymorphisms in ITGAM had the strongest association with <a href="/facts/Systemic_lupus_erythematosus/kfHYawre">systemic lupus erythematosus</a>, with an odds ratio of 1.65 for the T allele of rs9888739 and lupus.
In <a href="/facts/Histopathology/9Eggjrg4">histopathology</a>, immunohistochemistry with antibodies against CD11B is frequently used to identify <a href="/facts/Macrophages/z7hkQu3o">macrophages</a> and <a href="/facts/Microglia/fU9dhL72">microglia</a>.

Integrin alpha M open-in-new

Integrin alpha M