And around the cell, integrins and is mediated transmembrane receptor binding between the extracellular matrix or other cells of the (ECM). It is integrin signaling for transmitting information about the mechanical state of the ECM in the cell and chemical composition. Thus, in addition to the transmission of the film vulnerable against mechanical forces or else, they are involved in the regulation of movement and cell cycle intracellular signaling, and shape. I will inform cell receptor on the cell and molecular response of normal environment. Not only do this in signaling outside, integrins, but not operating mode from the inside. Therefore, in order to convert the information from the ECM into the cells, allowing the aggregation of platelets, for example, they show the outer state of the cell that allows a flexible response quickly to changes in the environment.


There are many types of integrin there, and has a number of types of cells on the surface of those many. Integrin is essential for all animals, and is found in all test animals from sponges to mammals. Integrin, has been extensively studied in humans. And cells – cells – cell integrin cadherin like to mediate communication and matrix interactions, cell adhesion molecules of the immunoglobulin superfamily, selectins, and working together with other proteins, such as syndecan. ECM components and integrins bind cell surface, such as laminin fibronectin, vitronectin, and collagen.


Integrin is anaerobic hetero, including a chain of two different called α (alpha) and β (beta) subunit. In mammals, the 8β subunits and 18α, genome of Drosophila encodes a subunit 2β and 5α slightly, nematode C. elegans, have the gene and 1β.Theα of β subunits and two α subunit Whereas yl, and through the plasma membrane, respectively, and has a small cytoplasmic domain and is characterized.

Further, in some embodiments of the subunit-subunit of β-1, 4 kinds exist, for example, is formed by differential splicing. Plasma membrane has been included studies.Integrin number, it depends on the sub-unit of another has a cytoplasmic domain short amino acid of 40-70 degree in general, but the variety and α of the β subunit about 24 unique integrin, which is created through the combination. An exception is a β4 subunit having a cytoplasmic domain of either amino acid number 1088, the most prominent cytoplasmic domains of membrane proteins. Length from the N-terminus of each chain that constitute the ligand-binding domain of the extracellular matrix of 5 nM final cell plasma membrane outside, of approximately 23 nM lying close to each other and of α β chain.


May be different to 160 kDa from the 90 kDa of the molecular weight of the integrin subunit. β subunit, cysteine-rich repeats four. Β subunit binds divalent cations some, Α. The role of divalent cations in the α subunit is unknown, it is possible to stabilize the folding of the protein. cations β subunit is critical: they are involved in the adjustment of at least some of the ligand binding to integrins directly. There are different methods for classifying integrin. For example, a portion of the α-chain, because it has a structure similar to that found in the von Willebrand factor, A-domain protein, called a structure additional elements (“domains”) or (In addition, it also) N-terminal α-domain is called α-I domain. (For example, α2β1 integrin and α1β1) in collagen, or carry or bind this domain, integrin functions as a cell-cell adhesion molecule. The α-I domain is a ligand binding site of integrin thereof. Do not carry this field, also integrins of these, it adds to the domain of the ligand binding site of them, this domain is a β subunit.


In both cases the domain to carry up to binding sites of trivalent cation. It is the presence of a constant at physiological concentrations of divalent cations, one, the major divalent cations in the blood average density 0.8 mm in (magnesium) or magnesium ion, calcium 1.4 mm and (calcium) I carry. For these ligands containing an acidic amino acid in the interaction site of their two positions at the time of binding ligands other, are occupied by cations, at least. The amino acid sequence arginine – glycine – as part of aspartic acid, proteins many ECM, for example, to amino acid functional interactions integrins.

In spite of many years of effort, the difficult proof identification high-resolution structure of integrins: membrane protein is a classic difficult to purify, integrin is complex and large-scale, wood sugar of many (“advanced and is associated with glycosylation “). Resulting GPIIbIIIa, ultracentrifugation Furthermore, low resolution image of the detergent extract data Methods indirect and determine the nature of the solution of the integrin using light scattering, occasional high using integrin electron microscope intact domain or a pair of single molecule model and single integrin chain to be mixed with NMR or crystallographic data resolution was assumed for other chain.

X-ray crystal structure despite extensive efforts described above were obtained for eligible extracellular region integrins, integrin αvβ3 was surprising. It showed a molecular profile inverted bent in a V-shape having a ligand binding site near the cell membrane and potentially. Crystal structure also RGD sequence, more importantly perhaps, obtained the same integrin associated with small ligands, including drug cilengitide. The reason is important for binding of the ligand to the integrin RGD divalent cations (domains), as indicated above, it has been clarified in the end. These sequences, ECM is considered to be the key and influence the behavior of the cell interaction with the integrin.

Structure raises a number of issues with respect to signaling and ligand binding in particular. Ligand-binding site is directed towards C-terminus of the integrin molecule-out area of ​​the cell membrane. It would seem to be closed, if it is found vertically from the ligand binding site of the membrane, usually, a large ECM, integrin ligand is dependent components particularly well. In fact, is known about the angularly dependent membrane proteins on the surface of the film is little, it is a difficult problem to deal with the existing technologies. The default assumption, is that they look like candy smaller, but evidence for this assumption is sweet aware of its absence. May affect general how membrane proteins of works, integrin structure is attracting attention to this problem. It extracellular loop (hereinafter, please refer to “Enable”) seems to be tilted helix through integrins, suggesting that it can not be perpendicular to the surface of the membrane.

It has changed a little surprisingly after binding to the crystal structure cilengitide but, with a change in the shape of the displacement of the ligand binding site is located in a more accessible location from the cell surface integrin function is away, this hypothesis, also occurs this shape change intracellular signaling you have. Body wide biochemical literature and cell biological, supports this goal. Most convincing proof involves the use of antibodies recognizing the integrin only be activated or they are connected to their ligands probably. Since about 3 microns in diameter “mark” that performs antibody binding target range, the resolution of this technique is lower. However, I shows that significant changes in the form integrin occurs on a daily basis is clearly (ligand-induced binding site) antibody so-called LIBS these. However, changes how was detected by an antibody, the structure is still unknown, but it is displayed.

Integrin is a pair of (micro filament especially) non-ECM cytoskeleton of cells. ECM integrin ligand may be coupled with the determination of the integrin α β subunit has been executed. It is a laminin fibronectin, vitronectin, and collagen in the ligand of integrin. The relationship between the ECM and cells, can help cells to withstand the pulling force without being ripped off by the ECM. Capacity of the cells, is essential for ontogeny to create this type of connection.

Mobile phone that is connected to the ECM, is a basic requirement for the development of multicellular organisms. Integrin is not a mere hook, but the cell phone signal, I will give you the important nature of the surroundings. And human and many other signal, from the soluble receptor of the growth factor VEGF, such as this, such as EGF, whether it be differentiated love, movement, death and they, the biological action together I apply the cell solution to what it takes. Therefore cell biological processes underlying many integrin. Adhesion of cells is composed of cytoplasmic proteins and integrins like many paxillin α-actin Tallinn, and vinculin, such complex formation, cell adhesion, passes. By act by regulating the kinase as a Src kinase family member FAK and (focal adhesion kinase), etc. to phosphorylate substrates, they adopted the phosphorus signaling p130CAS adapters such CRK such . Such complexes make the attachment of the actin cytoskeleton. ECM extracellular and intracellular actin Therefore fiber Association, integrin that serves to connect the two networks in the plasma membrane. It binds to the keratin intermediate filament system in epithelial cells: are exceptions Alpha6beta4 integrin.
They After assembly, the focal adhesions is a significant molecular complex obtained after interaction of integrin and ECM.