ITGB4
Domain
The VWFA domain (or beta I domain) contains three cation-binding sites: the ligand-associated metal ion-binding site (LIMBS or SyMBS), the metal ion-dependent adhesion site (MIDAS), and the adjacent MIDAS site (ADMIDAS). This domain is also part of the ligand-binding site.
The fibronectin type-III-like domains bind BPAG1 and plectin and probably also recruit BP230.
Function
Integrin alpha-6/beta-4 is a receptor for laminin. Plays a critical structural role in the hemidesmosome of epithelial cells. Is required for the regulation of keratinocyte polarity and motility. ITGA6:ITGB4 binds to NRG1 (via EGF domain) and this binding is essential for NRG1-ERBB signaling (PubMed:20682778). ITGA6:ITGB4 binds to IGF1 and this binding is essential for IGF1 signaling (PubMed:22351760). ITGA6:ITGB4 binds to IGF2 and this binding is essential for IGF2 signaling (PubMed:28873464).
Involvement in disease
Epidermolysis bullosa, junctional 5A, intermediate
JEB5A
A form of epidermolysis bullosa, a genodermatosis characterized by recurrent blistering, fragility of the skin and mucosal epithelia, and erosions caused by minor mechanical trauma. JEB5A is an autosomal recessive, intermediate form in which blistering lesions occur between the epidermis and the dermis at the lamina lucida level of the basement membrane zone. In intermediate forms of junctional epidermolysis bullosa, blistering does not lead to the formation of chronic granulation tissue and does not affect the lifespan of affected individuals. Nail dystrophy and dental enamel defects are present. Scarring or non-scarring alopecia and diffuse hair loss may occur.
None
The disease is caused by variants affecting the gene represented in this entry.
Epidermolysis bullosa, junctional 5B, with pyloric atresia
JEB5B
A form of epidermolysis bullosa, a genodermatosis characterized by recurrent blistering, fragility of the skin and mucosal epithelia, and erosions caused by minor mechanical trauma. Junctional epidermolysis bullosa is characterized by blistering that occurs at the level of the lamina lucida in the skin basement membrane. JEB5B is an autosomal recessive, severe, frequently lethal form with variable involvement of skin, nails, mucosa, and with variable effects on the digestive system. It is characterized by mucocutaneous fragility, aplasia cutis congenita, and gastrointestinal atresia, which most commonly affects the pylorus. Pyloric atresia is a primary manifestation rather than a scarring process secondary to epidermolysis bullosa.
None
The disease is caused by variants affecting the gene represented in this entry.
Post-translational modifications
Palmitoylated by DHHC3 at several cysteines of the membrane-proximal region, enhancing stability and cell surface expression. Palmitoylation also promotes secondary association with tertaspanins.
Sequence Similarities
Belongs to the integrin beta chain family.
Tissue Specificity
Integrin alpha-6/beta-4 is predominantly expressed by epithelia. Isoform beta-4D is also expressed in colon and placenta. Isoform beta-4E is also expressed in epidermis, lung, duodenum, heart, spleen and stomach.
Cellular localization
- Cell membrane
- Single-pass type I membrane protein
- Cell membrane
- Lipid-anchor
- Cell junction
- Hemidesmosome
- Colocalizes with DST at the leading edge of migrating keratinocytes.
Alternative names
CD104, Integrin beta-4, GP150, ITGB4