Integrin alpha M

ITGAM
Available structures PDB Ortholog search: PDBe RCSB List of PDB id codes 1BHO, 1BHQ, 1IDN, 1IDO, 1JLM, 1M1U, 1MF7, 1N9Z, 1NA5, 2LKE, 2LKJ, 3Q3G, 3QA3, 4M76, 4XW2
Identifiers
Aliases	ITGAM, CD11B, CR3A, MAC-1, MAC1A, MO1A, SLEB6, integrin subunit alpha M
External IDs	OMIM: 120980; MGI: 96607; HomoloGene: 526; GeneCards: ITGAM; OMA:ITGAM - orthologs
Gene location (Human) Chr. Chromosome 16 (human)[1] Band 16p11.2 Start 31,259,967 bp[1] End 31,332,892 bp[1]
Gene location (Mouse) Chr. Chromosome 7 (mouse)[2] Band 7|7 F3 Start 127,661,812 bp[2] End 127,717,663 bp[2]
RNA expression pattern Bgee Human Mouse (ortholog) Top expressed in monocyte granulocyte trabecular bone bone marrow blood bone marrow cells spleen appendix upper lobe of left lung decidua Top expressed in granulocyte bone marrow ileum jejunum spleen dentate gyrus of hippocampal formation granule cell hippocampus proper esophagus striatum of neuraxis uterus More reference expression data BioGPS More reference expression data
Gene ontology Molecular function metal ion binding protein binding protein heterodimerization activity heat shock protein binding amyloid-beta binding complement component C3b binding cargo receptor activity Cellular component extracellular exosome plasma membrane cell surface membrane integral component of membrane integrin complex extracellular space specific granule membrane tertiary granule membrane external side of plasma membrane integrin alphaM-beta2 complex plasma membrane raft membrane raft Biological process ectodermal cell differentiation toll-like receptor 4 signaling pathway integrin-mediated signaling pathway leukocyte migration extracellular matrix organization cell adhesion neutrophil degranulation microglial cell activation immune system process receptor-mediated endocytosis phagocytosis, engulfment cytokine-mediated signaling pathway positive regulation of superoxide anion generation positive regulation of neutrophil degranulation innate immune response negative regulation of dopamine metabolic process positive regulation of protein targeting to membrane amyloid-beta clearance cell-cell adhesion via plasma-membrane adhesion molecules complement-mediated synapse pruning vertebrate eye-specific patterning positive regulation of neuron death positive regulation of microglial cell activation positive regulation of microglial cell mediated cytotoxicity cell surface receptor signaling pathway involved in cell-cell signaling positive regulation of prostaglandin-E synthase activity forebrain development apoptotic signaling pathway positive regulation of hippocampal neuron apoptotic process Sources:Amigo / QuickGO
Orthologs Species Human Mouse Entrez 3684 16409 Ensembl ENSG00000169896 ENSMUSG00000030786 UniProt P11215 P05555 RefSeq (mRNA) NM_000632 NM_001145808 NM_001082960 NM_008401 RefSeq (protein) NP_000623 NP_001139280 n/a Location (UCSC) Chr 16: 31.26 – 31.33 Mb Chr 7: 127.66 – 127.72 Mb PubMed search [3] [4]
Wikidata
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Integrin alpha M (ITGAM) is one protein subunit that forms heterodimeric integrin alpha-M beta-2 (α_Mβ₂) molecule, also known as macrophage-1 antigen (Mac-1) or complement receptor 3 (CR3).^[5] ITGAM is also known as CR3A, and cluster of differentiation molecule 11B (CD11B). The second chain of α_Mβ₂ is the common integrin β₂ subunit known as CD18, and integrin α_Mβ₂ thus belongs to the β₂ subfamily (or leukocyte) integrins.^[6]

α_Mβ₂ is expressed on the surface of many leukocytes involved in the innate immune system, including monocytes, granulocytes, macrophages, and natural killer cells ^[5] and subsets of T and B cells.^[7] It mediates inflammation by regulating leukocyte adhesion and migration and has been implicated in several immune processes such as phagocytosis, cell-mediated cytotoxicity, chemotaxis and cellular activation.^[5] It is involved in the complement system due to its capacity to bind inactivated complement component 3b (iC3b).^[8] The ITGAM (alpha) subunit of integrin α_Mβ₂ is directly involved in causing the adhesion and spreading of cells but cannot mediate cellular migration without the presence of the β2 (CD18) subunit.^[5]

In genomewide association studies, single nucleotide polymorphisms in ITGAM had the strongest association with systemic lupus erythematosus, with an odds ratio of 1.65 for the T allele of rs9888739 and lupus.^[9][10]

In histopathology, immunohistochemistry with antibodies against CD11B is frequently used to identify macrophages and microglia.