integrin alpha4-beta7 complex

Definition

Target type: cellularcomponent

An integrin complex that comprises one alpha4 subunit and one beta7 subunit. [PMID:12297042]

The integrin alpha4-beta7 complex is a transmembrane protein found on the surface of lymphocytes, particularly T cells and some B cells. This complex plays a crucial role in the homing of lymphocytes to the gut, a process vital for immune surveillance and response within the gastrointestinal tract. The cellular component of this complex can be described in detail as follows:

**Extracellular Domain:**
- The extracellular domain of the alpha4-beta7 complex consists of two subunits, alpha4 and beta7, which interact to form a heterodimer.
- The alpha4 subunit, with its characteristic I-domain, binds to the vascular cell adhesion molecule 1 (VCAM-1) expressed on the endothelium of the gut-associated lymphoid tissues (GALT). This interaction facilitates the tethering and rolling of lymphocytes along the GALT endothelium.
- The beta7 subunit binds to mucosal addressin cell adhesion molecule 1 (MAdCAM-1), another adhesion molecule expressed on the GALT endothelium. This binding is crucial for the firm adhesion and transmigration of lymphocytes across the GALT endothelium.

**Transmembrane Domain:**
- Both the alpha4 and beta7 subunits contain transmembrane domains that anchor the complex to the plasma membrane of the lymphocyte.

**Cytoplasmic Domain:**
- The cytoplasmic domains of the alpha4 and beta7 subunits interact with intracellular signaling proteins, including talin and kindlin. These interactions are essential for the activation of the integrin complex and its ability to bind to its ligands.

**Association with Actin Cytoskeleton:**
- Through its interactions with talin and kindlin, the integrin alpha4-beta7 complex is linked to the actin cytoskeleton of the lymphocyte. This connection provides structural support and facilitates the migration of lymphocytes towards the gut.'
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Proteins (2)

Compounds (6)