Integrin beta 4

Integrin beta 4 (also known as ITGB4) is a protein that in humans is encoded by the ITGB4 gene. It is a member of the integrin family and is involved in cell adhesion and recognition in a variety of processes including embryogenesis, hemostasis, tissue repair, immune response and metastatic diffusion of tumor cells.

Structure

File:Integrin beta 4 structure.png

Structure of Integrin beta 4

Integrin beta 4 is a type I membrane protein found in hemidesmosomes. It consists of a large extracellular domain, a single transmembrane segment, and a short cytoplasmic tail. The extracellular domain is composed of a seven-bladed beta-propeller, a thigh domain, two calf domains, and a beta-tail domain. The cytoplasmic tail contains several phosphorylation sites and binding sites for proteins such as SHC1 and GRB2.

Function

Integrin beta 4 is a receptor for fibronectin and laminin. It recognizes the sequence Arg-Gly-Asp (RGD) in its ligands. Upon ligand binding, ITGB4 triggers various intracellular pathways that regulate cell growth, survival, migration, and invasion.

Clinical significance

Mutations in the ITGB4 gene are associated with Epidermolysis bullosa, a group of genetic conditions that cause the skin to be very fragile and to blister easily. In addition, overexpression of ITGB4 has been observed in several types of cancer, including breast, colon, and lung cancer, and is associated with poor prognosis.

See also

• Integrin
• Epidermolysis bullosa
• Fibronectin
• Laminin

External links

• GeneCards - ITGB4