What are focal adhesions? Focal adhesions are integrin-containing, multi-protein structures that form mechanical links between intracellular actin bundles and the extracellular matrix or substrate in many cell types [1]. The formation and function of focal adhesions can be described over defined steps that include [...]
How are proteins recruited to focal adhesion sites? The chronological order of protein recruitment into focal adhesions leads to the concept of sequential assembly. Accordingly, the exact composition of each elongating adhesions is dependent on their age. The dynamics of component recruitment within individual [...]
How do focal adhesions disassemble? Disassembly is critical during cell spreading and forward movement to allow FAs to extend outwards towards the cell periphery [1]. Disassembly of adhesions can take place as a result of retraction at the rear of the cell after adhesion [...]
How do focal adhesions mature? Adhesions that manage to grow beyond the transient phase further undergo qualitative changes in a phase described as maturation. This transformation of adhesion sites into stress-fiber bound focal adhesions (FAs) is believed to result from the collective effects of [...]
What are mature focal adhesions composed of? Mature FAs vary in size between 1 to 5 µm and to date, more than 80 types of proteins (~150 proteins) have been located in the FA plaque [1] although not all interactions have been proven in [...]
What is the first step in focal adhesion assembly? Focal adhesion formation is initiated upon the binding of adhesion receptors to extracellular matrix (ECM) ligands (e.g. fibronectin, vitronectin, collagen) along the cell periphery usually at the protruding edge of a cell. Both intracellular and [...]
What is the role of integrin clustering in focal adhesion assembly? There is still much debate over the mechanisms of signal transduction following integrin-ligand binding, however recent studies reveal that irrespective of the global density of integrins, local clustering of ligand-bound integrins is paramount [...]
What is the role of Rho GTPases in the regulation of focal adhesion assembly? Synergistic integrin-syndecan signaling The rate and extent of focal adhesion formation and maturation are regulated by factors such as synergistic integrin–syndecan signaling and alternating activation cycles of Rho (Rac1, Cdc42 [...]
How do nascent adhesions grow into mature focal adhesions? Nascent adhesions undergo a transient phase of rapid assembly and disassembly through which a fraction of adhesions survive to evolve into more stable and larger focal adhesions. Typically adhesions during this time vary in size [...]
What steps are involved in the formation of focal adhesions? The assembly of focal adhesions is highly regulated, with protein recruitment occurring in a sequential manner [1], and resulting in structures that are organized in specific layers that corresponding to the following functions: Receptor-matrix [...]
What are actin filaments? Actin filaments (F-actin) are linear polymers of globular actin (G-actin) subunits and occur as microfilaments in the cytoskeleton and as thin filaments, which are part of the contractile apparatus, in muscle and nonmuscle cells (see contractile bundles). They commonly underlie [...]
What is the Cytoskeleton? The eukaryotic cytoskeleton is a network of three long filament systems, made from the repetitive assembly and disassembly of dynamic protein components. The primary filament systems comprising the cytoskeleton are microtubules, actin filaments, and intermediate filaments. It creates an internal [...]
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One of four Research Centres of Excellence at NUS, MBI is working to identify, measure and describe how the forces for motility and morphogenesis are expressed at the molecular, cellular and tissue level.