Integrin alpha M (ITGAM) is one protein subunit that forms heterodimeric

integrin Integrins are transmembrane receptors that facilitate cell-cell and cell-extracellular matrix (ECM) adhesion. Upon ligand binding, integrins activate signal transduction pathways that mediate cellular signals such as regulation of the cell cycle ...

alpha-M beta-2 (α_Mβ₂) molecule, also known as '' macrophage-1 antigen'' (Mac-1) or ''

complement receptor A complement receptor is a membrane-bound receptor belonging to the complement system, which is part of the innate immune system. Complement receptors bind effector protein fragments that are produced in response to antigen-antibody complexes or ...

3'' (CR3). ITGAM is also known as CR3A, and

cluster of differentiation The cluster of differentiation (also known as cluster of designation or classification determinant and often abbreviated as CD) is a protocol used for the identification and investigation of cell surface molecules providing targets for immunophen ...

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. α_Mβ₂ is expressed on the surface of many leukocytes involved in the innate immune system, including

monocyte Monocytes are a type of leukocyte or white blood cell. They are the largest type of leukocyte in blood and can differentiate into macrophages and conventional dendritic cells. As a part of the vertebrate innate immune system monocytes also ...

s, granulocytes, macrophages, and natural killer cells. It mediates inflammation by regulating leukocyte

adhesion Adhesion is the tendency of dissimilar particles or surfaces to cling to one another ( cohesion refers to the tendency of similar or identical particles/surfaces to cling to one another). The forces that cause adhesion and cohesion can b ...

and migration and has been implicated in several immune processes such as

phagocytosis Phagocytosis () is the process by which a cell uses its plasma membrane to engulf a large particle (≥ 0.5 μm), giving rise to an internal compartment called the phagosome. It is one type of endocytosis. A cell that performs phagocytosis is ...

, cell-mediated cytotoxicity, chemotaxis and cellular activation. It is involved in the complement system due to its capacity to bind inactivated complement component 3b (iC3b). 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. 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. In histopathology, immunohistochemistry with antibodies against CD11B is frequently used to identify

macrophages Macrophages (abbreviated as M φ, MΦ or MP) ( el, large eaters, from Greek ''μακρός'' (') = large, ''φαγεῖν'' (') = to eat) are a type of white blood cell of the immune system that engulfs and digests pathogens, such as cancer ce ...

and microglia.

References

External links

*
Mouse CD Antigen Chart

ITGAM
Info with links in th
Cell Migration Gateway
Integrins {{gene-16-stub

See also

References

Further reading

External links