integrin alpha3-beta1 complex

Definition

Target type: cellularcomponent

An integrin complex that comprises one alpha3 subunit and one beta1 subunit. [PMID:12297042]

The integrin alpha3-beta1 complex is a transmembrane receptor that plays a crucial role in cell adhesion, migration, and signaling. It is composed of two subunits: the alpha3 subunit and the beta1 subunit.

**Cellular Component:**

The alpha3-beta1 complex is localized to the cell surface, specifically at focal adhesions and hemidesmosomes.

* **Focal adhesions** are specialized structures that connect the intracellular cytoskeleton to the extracellular matrix (ECM). They are dynamic sites of cell adhesion, where integrins interact with ECM components, such as fibronectin, collagen, and laminin, and transmit signals to the cell interior.

* **Hemidesmosomes** are specialized cell-matrix junctions that provide strong adhesion between epithelial cells and the underlying basement membrane. They are characterized by the presence of intermediate filaments, such as keratin, that connect to the cytoplasmic domain of the beta1 subunit.

**Structure:**

The alpha3-beta1 complex is a heterodimer, consisting of an alpha3 subunit and a beta1 subunit. Both subunits are transmembrane proteins with extracellular, transmembrane, and cytoplasmic domains.

* **Extracellular domains:** The extracellular domains of the alpha3 and beta1 subunits interact with each other and with ECM components. The alpha3 subunit contains a large, globular head domain that is responsible for binding to ECM proteins, such as laminin. The beta1 subunit contains a smaller head domain and a flexible stalk region that connects the head domain to the transmembrane domain.

* **Transmembrane domains:** The transmembrane domains of the alpha3 and beta1 subunits anchor the complex to the cell membrane.

* **Cytoplasmic domains:** The cytoplasmic domains of the alpha3 and beta1 subunits interact with intracellular proteins, such as talin, kindlin, and paxillin. These interactions are essential for the formation of focal adhesions and hemidesmosomes and for signal transduction.

**Function:**

The alpha3-beta1 complex plays a crucial role in various cellular processes, including:

* **Cell adhesion:** Integrins are key mediators of cell adhesion, and the alpha3-beta1 complex is particularly important for the adhesion of epithelial cells to the basement membrane.

* **Cell migration:** Integrins are also involved in cell migration, and the alpha3-beta1 complex plays a role in the migration of epithelial cells during wound healing and development.

* **Signal transduction:** Integrins can act as signal transducers, converting extracellular cues into intracellular signals that regulate cell behavior. The alpha3-beta1 complex is involved in signaling pathways that regulate cell proliferation, survival, and differentiation.

**Clinical significance:**

Mutations in the genes encoding the alpha3 and beta1 subunits can lead to various diseases, including:

* **Epidermolysis bullosa:** A group of genetic skin disorders characterized by blistering and skin fragility. Mutations in the alpha3 subunit are associated with junctional epidermolysis bullosa.

* **Cancer:** The alpha3-beta1 complex is overexpressed in some cancers, where it contributes to tumor cell invasion and metastasis.

* **Other diseases:** The alpha3-beta1 complex has also been implicated in other diseases, such as cardiovascular disease, inflammatory bowel disease, and Alzheimer's disease.'
"

Proteins (2)

Compounds (17)