| Beta7 | integrin β7 subunit |
| Molecule Type | Antigen Expression | Molecular Weight Min / Max |
| Lineage Restricted Molecule Type 1 glycoprotein | Lymphocyte | 100 / 115 |
Expression | ||||||||||||||||||||
| b7 combines with the a4 subunit CD49d to form the a4b7 integrin and with the aE subunit CD103 to form the aEb7 integrin HML-1. Both antigens are expressed on mucosal lymphocytes. Adult human lymphocytes have a heterogeneous expression of a4b7, whereas expression on newborn lymphocytes is more homogeneous. a4b7 is also expressed on NK cells and eosinophils. a4b7 is expressed on 95% of intraepithelial lymphocytes but only 1%-2% on peripheral blood lymphocytes. Its level of expression on lymphocytes can be upregulated by lymphocyte mitogens. | ||||||||||||||||||||
Structure | ||||||||||||||||||||
| The b7 integrin subunit is a single chain type 1 glycopeptide. It is most closely related to the b2 integrin subunit CD18 including the cytoplasmic segment, in which 2 NPX Y/F motifs for potential tyrosine kinase binding are found. Most integrin b subunits have 56 conserved cysteine-residues in their extracellular portion. The last 2 cysteines are missing from the b7 subunit. The N-terminus has been determined by protein sequencing. MOLECULAR MASS
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Ligands | ||||||||||||||||||||
| Like the a4b1 integrin, a4b7 binds CD106 VCAM-1 and the CS1 region of fibronectin. In addition, a4b7 binds the mucosal addressin MAdCAM-1. aEb7 binds E-cadherin on epithelial cells. | ||||||||||||||||||||
Function | ||||||||||||||||||||
| The a4b7 integrin mediates the binding of lymphocytes to MAdCAM-1 on the high endothelial venules, thereby directing the homing of lymphocytes into Peyer's patches and the intestinal lamina propria. The interaction between aEb7 and E-cadherin may be of importance in the homing and retention of aEb7 expressing lymphocytes to the intestinal epithelium. | ||||||||||||||||||||
Comments | ||||||||||||||||||||
Database accession numbers | ||||||||||||||||||||
Revised June 25, 2008
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