Integrin alpha M

Integrin, alpha M (complement component 3 receptor 3 subunit)
PDB rendering based on 1bho.
Available structures PDB Ortholog search: PDBe, RCSB List of PDB id codes 1A8X​, 1BHO​, 1BHQ​, 1IDN​, 1IDO​, 1JLM​, 1M1U​, 1MF7​, 1N9Z​, 1NA5​, 2LKE​, 2LKJ​, 3Q3G​, 3QA3​, 4M76​
Identifiers
Symbols	ITGAM ; CD11B; CR3A; MAC-1; MAC1A; MO1A; SLEB6
External IDs	OMIM: 120980 MGI: 96607 HomoloGene: 526 ChEMBL: 3826 GeneCards: ITGAM Gene
Gene ontology Molecular function • opsonin binding • glycoprotein binding • protein binding • heparin binding • heparan sulfate proteoglycan binding • metal ion binding Cellular component • extracellular space • nucleus • plasma membrane • integrin complex • external side of plasma membrane • cell surface • extracellular exosome Biological process • toll-like receptor signaling pathway • leukocyte migration involved in inflammatory response • cell adhesion • integrin-mediated signaling pathway • blood coagulation • ectodermal cell differentiation • microglia development • extracellular matrix organization • neutrophil chemotaxis • toll-like receptor 4 signaling pathway • innate immune response • cellular extravasation • activated T cell proliferation • leukocyte migration Sources: Amigo / QuickGO
RNA expression pattern
More reference expression data
Orthologs
Species	Human	Mouse
Entrez	3684	16409
Ensembl	ENSG00000169896	ENSMUSG00000030786
UniProt	P11215	P05555
RefSeq (mRNA)	NM_000632	NM_001082960
RefSeq (protein)	NP_000623	NP_001076429
Location (UCSC)	Chr 16: 31.26 – 31.33 Mb	Chr 7: 128.06 – 128.13 Mb
PubMed search

Integrin alpha M (ITGAM) is one protein subunit that forms the heterodimeric integrin alpha-M beta-2 (α_Mβ₂) molecule, also known as macrophage-1 antigen (Mac-1) or complement receptor 3 (CR3).^[1] 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.^[2]

α_Mβ₂ is expressed on the surface of many leukocytes involved in the innate immune system, including monocytes, granulocytes, macrophages, and natural killer cells.^[1] 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.^[1] It is involved in the complement system due to its capacity to bind inactivated complement component 3b (iC3b).^[3] 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.^[1]

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.^[4][5]

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

See also

• integrin

References

1. Solovjov D, Pluskota E, Plow E (2005). "Distinct roles for the alpha and beta subunits in the functions of integrin alphaMbeta2". J Biol Chem 280 (2): 1336–45. doi:10.1074/jbc.M406968200. PMID 15485828.
2. Larson R, Springer T (1990). "Structure and function of leukocyte integrins". Immunol Rev 114: 181–217. doi:10.1111/j.1600-065X.1990.tb00565.x. PMID 2196220.
3. Arnaout M, Todd R, Dana N, Melamed J, Schlossman S, Colten H (1983). "Inhibition of phagocytosis of complement C3- or immunoglobulin G-coated particles and of C3bi binding by monoclonal antibodies to a monocyte-granulocyte membrane glycoprotein (Mol)". J Clin Invest 72 (1): 171–9. doi:10.1172/JCI110955. PMC 1129172. PMID 6874946.
4. Mary K. Crow (February 28, 2008). "Collaboration, Genetic Associations, and Lupus Erythematosus". N Engl J Med 358 (9): 956–961. doi:10.1056/NEJMe0800096. PMID 18204099.
5. Geoffrey Hom, Robert R. Graham, Barmak Modrek; et al. (February 28, 2008). "Association of Systemic Lupus Erythematosus with C8orf13–BLK and ITGAM–ITGAX". N Engl J Med 358 (9): 900–909. doi:10.1056/NEJMoa0707865. PMID 18204098.

Further reading

• Stewart M, Thiel M, Hogg N (1996). "Leukocyte integrins.". Curr. Opin. Cell Biol. 7 (5): 690–6. doi:10.1016/0955-0674(95)80111-1. PMID 8573344.
• Todd RF, Petty HR (1997). "Beta 2 (CD11/CD18) integrins can serve as signaling partners for other leukocyte receptors.". J. Lab. Clin. Med. 129 (5): 492–8. doi:10.1016/S0022-2143(97)90003-2. PMID 9142045.
• Schymeinsky J, Mócsai A, Walzog B (2007). "Neutrophil activation via beta2 integrins (CD11/CD18): molecular mechanisms and clinical implications.". Thromb. Haemost. 98 (2): 262–73. doi:10.1160/th07-02-0156. PMID 17721605.

External links

• Integrin alphaM at the US National Library of Medicine Medical Subject Headings (MeSH)
• Mouse CD Antigen Chart
• Human CD Antigen Chart
• ITGAM Info with links in the Cell Migration Gateway