Integrins, receptors for the extracellular matrix

Integrins, function and structure

Integrins are a family of transmembrane receptor proteins, connecting the cy-toskeleton with the extracellular matrix (ECM). Integrins bind to ECM glycopro-teins including collagens, fibronectins, laminins, and a number of cellular receptors. In addition, integrins function as signal transducers. Importantly, different integrins activate differential intracellular signaling pathways that control biological and cellular functions including cell adhesion, migration, proliferation, cell differentiation, and apoptosis (Schwartz et al. 1995).

Integrins are formed by two noncovalent-ly bound alpha and beta subunits. There are 18 alpha and 8 beta subunits, forming at least 24 distinct integrin heterodimers. Each heterodimer consists of a large extracellular domain, binding proteins in the extracellular environment, a single-membrane-spanning transmembrane domain, and a generally small intracellular cytoplasmic tail domain, which forms links with the cytoskeletal elements (Hynes 2002).



Immunocytochemical staining using monoclonal Anti-ITGB8 (AMAb91467) of WM-115 cells showing specific staining in the plasma membrane in green.



Immunohistochemical stainings of human placenta using (left) monoclonal antibody Anti-ITGA6 (AMAb91450) and (right) monoclonal antibody Anti-ITGB4 (AMAb91453) showing identical pattern. The two integrins interact to form a laminin-binding Alpha6 Beta4 complex involved in cell migration and invasion.

Integrin specificity

The specificity of integrin binding to ECM components including laminins, collagens, and fibronectin depends on the extracellular domains of the alpha and beta integrin subunits. Integrins a1b1, a2b1, a10b1, and a11b1 represent the primary collagen receptors (Hynes 2002). Integrins a5b1, a8b1, aIIbb3 and the avb integrins are the major fibronectin receptors that bind in an RGD-dependent manner (van der Flier and Sonnenberg 2001). Finally, integrins a3b1, a6b1, a6b4 and a7b1 are the major laminin receptors (Belkin AM1 and Stepp MA 2000).

A selection of Atlas Antibodies offering against specific integrin subunits is summarized in the tables below.

Table 1. Selected antibodies for Integrin alpha subunits.

Gene/ProteinProduct NameCat. No.ApplicationsSelected Interaction PartnersInvolved In
ITGA1/CD49aAnti-ITGA1AMAb91461IHC*, WBITGB1, LAMA1Cell adhesion, inflammation, fibrosis
ITGA2/CD49b ​Anti-ITGA2AMAb91469IHC*, WBITGB1, LAMA1Cancer growth/invasion
ITGA3/CD49cAnti-TGA3AMAb91446IHC*, WBITGB1, ITGB4, ITGB5Laminin-binding, Cancer growth/invasion
ITGA4/CD49dAnti-ITGA4HPA074961ICC-IFITGB3, VCAMCancer
ITGA5/CD49e ​Anti-ITGA5AMAb91449IHC*, WBITGB1, ITGB3, ITGB5, FN1Cancer growth/invasion
ITGA6/CD49fAnti-ITGA6AMAb91450IHC*ITGB1, ITGB4Laminin-binding. Cancer invasion/metastasis/stem cells.
ITGA7/ITGA7Anti-ITGA7HPA008427IHC, ICC-IFITGB1Laminin-binding. Cancer
ITGA8/ITGA8Anti-ITGA8AMAb91468IHC*, WBITGB1Epithelial-to-mesenchymal transition.
ITGA11/ITGA11Anti-ITGA11HPA051813IHC*ITGB1Development, cancer
ITGAD/CD11DAnti-ITGADHPA026786IHCITGB2, ICAM3, VCAM1Extracellular matrix organisation, cell-cell adhesion, immune response
ITGAE/CD103Anti-ITGAEHPA036313IHC*ITGB7, CDH1Cancer
ITGAM/CD11bAnti-ITGAMAMAb90911IHC*, WBITGB2, ICAM1Immune system, monocytes
ITGAV/CD51​Anti-ITGAVHPA004856IHC, ICC-IFITGB1, ITGB3, ITGB5, ITGB6, ITGB8Cancer
ITGA2B/CD41Anti-ITGA2BHPA031170IHC*, WBITGB3Different, including metastasis
ITGAX/CD11cAnti-ITGAXAMAb90915IHC*, WBITGB2Cancer, leukemia

Table 2. Selected antibodies for Integrin beta subunits.

Gene/ProteinProduct NameCat. No.ApplicationsSelected Interaction PartnersInvolved In
ITGB1/CD29Anti-ITGB1/CD29HPA059297IHC*, WBITGA1, ITGA2, ITGA3, ITGA5, ITGA6, ITGA7, ITGA8, ITGA9, ITGA10, ITGA11, ITGAVLaminin-binding, Cancer growth/invasion
ITGB2/CD18Anti-ITGB2HPA016894IHC*, WB, ICC-IFITGAL, ITGAD, ITGAM, ITGAXImmune system
ITGB3/CD61Anti-ITGB3AMAb91470IHC*, WBITGA4, ITGA5, ITGA2B, ITGAVCancer
ITGB4/CD104Anti-ITGB4AMAb91454IHC*, WBITGA3, ITGA6, SMAD2, SMAD3Laminin-binding, Cancer growth/invasion
ITGB5/ITGB5Anti-ITGB5HPA001820IHCITGA3, ITGA5, ITGAVCancer, cell adhesion, survival
ITGB6/ITGB6Anti-ITGB6HPA023626IHC, ICC-IFITGAV, MAPK1, FN1Different diseases, cancer
ITGB8/ITGB8Anti-ITGB8AMAb91467IHC, WB ICC-IFITGAV, RHEB, FN1Cancer

* Products with enhanced validation for indicated application



Related to:
Brands: Atlas Antibodies
Product groups: Antibodies