Focal adhesion

Focaladhesiondetail

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cellmatadhes

Focal adhesion

Focal adhesions are specialized structures that form at the cell membrane where the cell adheres to the extracellular matrix (ECM). These complex assemblies are crucial for various cellular processes, including cell migration, signal transduction, and mechanotransduction. Focal adhesions serve as the primary sites where cells sense and respond to mechanical stimuli from their environment.

Structure

Focal adhesions are composed of clusters of transmembrane proteins known as integrins, which link the ECM to the intracellular cytoskeleton. The cytoplasmic tails of integrins interact with a variety of adaptor proteins, such as talin, vinculin, and paxillin, which in turn connect to actin filaments. This connection facilitates the transmission of mechanical forces and signals between the ECM and the cell interior.

Function

Focal adhesions play a pivotal role in:

• Cell migration: By forming and disassembling focal adhesions, cells can move across the ECM.
• Signal transduction: Focal adhesions act as signaling hubs, where various signaling pathways converge to regulate cell behavior.
• Mechanotransduction: They enable cells to sense and respond to mechanical forces, which is essential for processes like tissue development and wound healing.

Formation and Dynamics

The formation of focal adhesions is a dynamic process that involves the recruitment of integrins and adaptor proteins to sites of cell-ECM contact. This process is regulated by various signaling molecules, including Rho GTPases, focal adhesion kinase (FAK), and Src family kinases. The disassembly of focal adhesions is equally important and is mediated by proteolytic enzymes and changes in the phosphorylation state of focal adhesion components.

Clinical Significance

Abnormalities in focal adhesion dynamics are associated with various diseases, including cancer, where altered cell adhesion and migration contribute to tumor metastasis. Additionally, defects in focal adhesion components can lead to muscular dystrophies and other connective tissue disorders.

Related Pages

• Integrin
• Extracellular matrix
• Cell migration
• Signal transduction
• Mechanotransduction
• Rho GTPase
• Focal adhesion kinase
• Src family kinases