calcium-independent cell-matrix adhesion

Definition

Target type: biologicalprocess

The binding of a cell to the extracellular matrix via adhesion molecules that do not require the presence of calcium for the interaction. [GOC:hb]

Calcium-independent cell-matrix adhesion is a complex biological process that allows cells to adhere to the extracellular matrix (ECM) without relying on calcium ions. This process is crucial for maintaining tissue integrity, regulating cell behavior, and facilitating various cellular functions. Here's a detailed explanation:

**1. Key Molecules and Mechanisms:**

* **Integrins:** Integrins are transmembrane proteins that play a central role in cell-matrix adhesion. They consist of two subunits, α and β, which combine to form different integrin heterodimers.
* **Non-classical Integrins:** Unlike classical integrins that require calcium for adhesion, non-classical integrins like αvβ3 and αvβ5 are calcium-independent.
* **ECM Ligands:** These are molecules in the extracellular matrix that bind to integrins. Examples include:
* **Fibronectin:** A large glycoprotein that interacts with both classical and non-classical integrins.
* **Vitronectin:** A protein that binds to αvβ3 and αvβ5 integrins.
* **Laminin:** A multi-domain protein found in the basement membrane, often interacting with αvβ6 integrin.

**2. Adhesion Process:**

* **Integrin Binding:** Non-classical integrins bind to their specific ECM ligands, initiating adhesion.
* **Clustering and Aggregation:** Integrins, upon ligand binding, cluster together, forming focal adhesions or other specialized adhesive structures.
* **Signal Transduction:** Integrin binding triggers intracellular signaling cascades that regulate cytoskeletal rearrangements, gene expression, and cell behavior.
* **Focal Adhesion Kinase (FAK):** A key signaling molecule involved in integrin-mediated signaling pathways.
* **Small GTPases:** Proteins like Rac and Rho control cytoskeletal dynamics and cell migration.

**3. Cellular Functions:**

* **Cell Migration:** Calcium-independent cell-matrix adhesion is vital for cell migration, guiding cells along specific pathways.
* **Tissue Development and Repair:** This process is essential for the formation and repair of tissues, ensuring proper organization and stability.
* **Wound Healing:** Cell-matrix adhesion is critical for proper wound closure, involving cell migration and matrix deposition.
* **Angiogenesis:** The formation of new blood vessels is often regulated by calcium-independent cell-matrix interactions.

**4. Regulation and Modulation:**

* **Growth Factors:** Factors like TGF-β and VEGF can influence integrin expression and activity, modulating cell-matrix interactions.
* **Proteases:** Enzymes like matrix metalloproteinases (MMPs) can degrade ECM components, affecting adhesion and cell behavior.
* **Post-translational Modifications:** Integrin activity can be modulated by phosphorylation, glycosylation, and other post-translational modifications.

**5. Implications for Disease:**

* **Cancer Metastasis:** Malignant cells often exploit calcium-independent cell-matrix interactions to invade surrounding tissues and metastasize.
* **Wound Healing Disorders:** Defective cell-matrix adhesion can lead to impaired wound healing and chronic skin ulcers.
* **Vascular Diseases:** Dysregulation of calcium-independent cell-matrix adhesion contributes to cardiovascular problems like atherosclerosis.

In conclusion, calcium-independent cell-matrix adhesion is a fundamental process essential for many aspects of cell biology. Understanding this complex mechanism is crucial for unraveling normal tissue development, wound healing, and disease pathogenesis.'
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Proteins (2)

Compounds (18)