Integrin, beta 4 (ITGB4) also known as CD104 (Cluster of Differentiation 104), is a human gene. [5]
Integrins are heterodimers composed of alpha and beta subunits, that are noncovalently associated transmembrane glycoprotein receptors. Different combinations of alpha and beta polypeptides form complexes that vary in their ligand-binding specificities. Integrins mediate cell-matrix or cell-cell adhesion, and transduced signals that regulate gene expression and cell growth. This gene encodes the integrin beta 4 subunit, a receptor for the laminins. This subunit tends to associate with alpha 6 subunit and is likely to play a pivotal role in the biology of invasive carcinoma. Mutations in this gene are associated with epidermolysis bullosa with pyloric atresia. Multiple alternatively spliced transcript variants encoding distinct isoforms have been found for this gene. [5]
ITGB4 has been shown to interact with Collagen, type XVII, alpha 1, [6] [7] EIF6 [8] and Erbin. [9]
Hemidesmosomes are very small stud-like structures found in keratinocytes of the epidermis of skin that attach to the extracellular matrix. They are similar in form to desmosomes when visualized by electron microscopy, however, desmosomes attach to adjacent cells. Hemidesmosomes are also comparable to focal adhesions, as they both attach cells to the extracellular matrix. Instead of desmogleins and desmocollins in the extracellular space, hemidesmosomes utilize integrins. Hemidesmosomes are found in epithelial cells connecting the basal epithelial cells to the lamina lucida, which is part of the basal lamina. Hemidesmosomes are also involved in signaling pathways, such as keratinocyte migration or carcinoma cell intrusion.
Laminins are a family of glycoproteins of the extracellular matrix of all animals. They are major components of the basal lamina, the protein network foundation for most cells and organs. The laminins are an important and biologically active part of the basal lamina, influencing cell differentiation, migration, and adhesion.
Plectin is a giant protein found in nearly all mammalian cells which acts as a link between the three main components of the cytoskeleton: actin microfilaments, microtubules and intermediate filaments. In addition, plectin links the cytoskeleton to junctions found in the plasma membrane that structurally connect different cells. By holding these different networks together, plectin plays an important role in maintaining the mechanical integrity and viscoelastic properties of tissues.
Keratin 5, also known as KRT5, K5, or CK5, is a protein that is encoded in humans by the KRT5 gene. It dimerizes with keratin 14 and forms the intermediate filaments (IF) that make up the cytoskeleton of basal epithelial cells. This protein is involved in several diseases including epidermolysis bullosa simplex and breast and lung cancers.
In molecular biology, CD18 is an integrin beta chain protein that is encoded by the ITGB2 gene in humans. Upon binding with one of a number of alpha chains, CD18 is capable of forming multiple heterodimers, which play significant roles in cellular adhesion and cell surface signaling, as well as important roles in immune responses. CD18 also exists in soluble, ligand binding forms. Deficiencies in CD18 expression can lead to adhesion defects in circulating white blood cells in humans, reducing the immune system's ability to fight off foreign invaders.
Integrin beta-1 (ITGB1), also known as CD29, is a cell surface receptor that in humans is encoded by the ITGB1 gene. This integrin associates with integrin alpha 1 and integrin alpha 2 to form integrin complexes which function as collagen receptors. It also forms dimers with integrin alpha 3 to form integrin receptors for netrin 1 and reelin. These and other integrin beta 1 complexes have been historically known as very late activation (VLA) antigens.
Integrin alpha-3 is a protein that in humans is encoded by the ITGA3 gene. ITGA3 is an integrin alpha subunit. Together with beta-1 subunit, it makes up half of the α3β1 integrin duplex that plays a role in neural migration and corticogenesis, acted upon by such factors as netrin-1 and reelin.
Integrin beta-3 (β3) or CD61 is a protein that in humans is encoded by the ITGB3 gene. CD61 is a cluster of differentiation found on thrombocytes.
Collagen XVII, previously called BP180, is a transmembrane protein which plays a critical role in maintaining the linkage between the intracellular and the extracellular structural elements involved in epidermal adhesion, identified by Diaz and colleagues in 1990.
CD151 molecule, also known as CD151, is a human gene.
Collagen alpha-1(VII) chain is a protein that in humans is encoded by the COL7A1 gene. It is composed of a triple helical, collagenous domain flanked by two non-collagenous domains, and functions as an anchoring fibril between the dermal-epidermal junction in the basement membrane. Mutations in COL7A1 cause all types of dystrophic epidermolysis bullosa, and the exact mutations vary based on the specific type or subtype. It has been shown that interactions between the NC-1 domain of collagen VII and several other proteins, including laminin-5 and collagen IV, contribute greatly to the overall stability of the basement membrane.
Dystonin(DST), also known as bullous pemphigoid antigen 1 (BPAG1), isoforms 1/2/3/4/5/8, is a protein that in humans is encoded by the DST gene.
Integrin beta-5 is a protein that in humans is encoded by the ITGB5 gene.
Laminin subunit alpha-3 is a protein that in humans is encoded by the LAMA3 gene.
Integrin beta-6 is a protein that in humans is encoded by the ITGB6 gene. It is the β6 subunit of the integrin αvβ6. Integrins are αβ heterodimeric glycoproteins which span the cell’s membrane, integrating the outside and inside of the cell. Integrins bind to specific extracellular proteins in the extracellular matrix or on other cells and subsequently transduce signals intracellularly to affect cell behaviour. One α and one β subunit associate non-covalently to form 24 unique integrins found in mammals. While some β integrin subunits partner with multiple α subunits, β6 associates exclusively with the αv subunit. Thus, the function of ITGB6 is entirely associated with the integrin αvβ6.
Laminin subunit beta-3 is a protein that in humans is encoded by the LAMB3 gene.
Integrin beta-7 is an integrin protein that in humans is encoded by the ITGB7 gene. It can pair with ITGA4 (CD49d) to form the heterodimeric integrin receptor α4β7, or with ITGAE (CD103) to form αEβ7.
Eukaryotic translation initiation factor 6 (EIF6), also known as Integrin beta 4 binding protein (ITGB4BP), is a human gene.
Integrin beta-8 is a protein that in humans is encoded by the ITGB8 gene.
Junctional epidermolysis bullosa is a skin condition characterized by blister formation within the lamina lucida of the basement membrane zone.
This article incorporates text from the United States National Library of Medicine, which is in the public domain.