Function: Integrin alpha-6/beta-1 is a receptor for laminin on platelets. Integrin alpha-6/beta-4 is a receptor for laminin in epithelial cells and it plays a critical structural role in the hemidesmosome.
Subunit structure: Heterodimer of an alpha and a beta subunit. The alpha subunit is composed of a heavy and a light chain linked by a disulfide bond. Alpha-6 associates with either beta-1 or beta-4. Interacts with HPS5. Interacts with RAB21. Ref.21
Subcellular location: Cell membrane; Single-pass type I membrane protein.
Tissue specificity: Integrin alpha-6/beta-4 is predominantly expressed by epithelia. Isoforms containing segment X1 are ubiquitously expressed. Isoforms containing segment X1X2 are expressed in heart, kidney, placenta, colon, duodenum, myoblasts and myotubes, and in a limited number of cell lines; they are always coexpressed with the ubiquitous isoform containingsegment X1. In some tissues (e.g. Salivary gland), isoforms containing cytoplasmic segment A and isoforms containing segment B are detected while in others, only isoforms containing one cytoplasmic segment are found (segment A in epidermis and segment B in kidney). Ref.20
Post-translational modification: Isoforms containing segment A, but not segment B, are the major targets for PMA-induced phosphorylation. Phosphorylation occurs on 'Ser-1103' of isoform alpha-6X1X2A Phosphorylation is not required for the induction of integrin alpha-6A/beta-1 high affinity but may reduce the affinity for ligand.
Involvement in disease: Epidermolysis bullosa letalis, with pyloric atresia (EB-PA) [MIM:226730]: An autosomal recessive, frequently lethal, epidermolysis bullosa 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.Note: The disease is caused by mutations affecting the gene represented in this entry.
Sequence similarities: Belongs to the integrin alpha chain family.Contains 7 FG-GAP repeats.
Sequence caution: The sequence BAG57680.1 differs from that shown. Reason: Erroneous initiation. Translation N-terminally extended.
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