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 Macrophage-1 antigen (or integrin αMβ2 or macrophage integrin or Mac-1) is a complement receptor ("CR3") consisting of CD11b (integrin αM) and CD18 (integrin β2). The integrin α chain is noncovalently bound to the integrin β chain. It binds ...

'' (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

leukocyte White blood cells, also called leukocytes or leucocytes, are the cells of the immune system that are involved in protecting the body against both infectious disease and foreign invaders. All white blood cells are produced and derived from mult ...

s 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 ...

granulocyte Granulocytes are cells in the innate immune system characterized by the presence of specific granules in their cytoplasm. Such granules distinguish them from the various agranulocytes. All myeloblastic granulocytes are polymorphonuclear. They ha ...

macrophage 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 cel ...

s, and

natural killer cell Natural killer cells, also known as NK cells or large granular lymphocytes (LGL), are a type of cytotoxic lymphocyte critical to the innate immune system that belong to the rapidly expanding family of known innate lymphoid cells (ILC) and repres ...

s. 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 be ...

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 The complement system, also known as complement cascade, is a part of the immune system that enhances (complements) the ability of antibodies and phagocytic cells to clear microbes and damaged cells from an organism, promote inflammation, and at ...

due to its capacity to bind inactivated

complement component 3b Complement component 3, often simply called C3, is a protein of the immune system. It plays a central role in the complement system and contributes to innate immunity. In humans it is encoded on chromosome 19 by a gene called ''C3''. Function ...

(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 Lupus, technically known as systemic lupus erythematosus (SLE), is an autoimmune disease in which the body's immune system mistakenly attacks healthy tissue in many parts of the body. Symptoms vary among people and may be mild to severe. Comm ...

, with an odds ratio of 1.65 for the T allele of rs9888739 and lupus. In

histopathology Histopathology (compound of three Greek words: ''histos'' "tissue", πάθος ''pathos'' "suffering", and -λογία '' -logia'' "study of") refers to the microscopic examination of tissue in order to study the manifestations of disease. Spe ...

, 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