Motile cells extend a leading edge by assembling a branched network of actin filaments that produces physical force as the polymers grow beneath the plasma membrane. A core set of proteins including actin, Arp2/3 complex, profilin, capping protein, and ADF/cofilin can reconstitute the process in vitro, and mathematical models of the constituent reactions predict the rate of motion. Signaling pathways converging on WASp/Scar proteins regulate the activity of Arp2/3 complex, which mediates the initiation of new filaments as branches on preexisting filaments. After a brief spurt of growth, capping protein terminates the elongation of the filaments. After filaments have aged by hydrolysis of their bound ATP and dissociation of the gamma phosphate, ADF/cofilin proteins promote debranching and depolymerization. Profilin catalyzes the exchange of ADP for ATP, refilling the pool of ATP-actin monomers bound to profilin, ready for elongation.
Pubmed ID: 12600310 RIS Download
Mesh terms: Actin Depolymerizing Factors | Actins | Adenosine Diphosphate | Adenosine Triphosphate | Animals | Cattle | Cell Division | Cell Membrane | Cell Movement | Cell Nucleus | Crystallography, X-Ray | Dendrites | Keratinocytes | Microfilament Proteins | Models, Biological | Models, Molecular | Phosphates | Protein Structure, Secondary | Protein Structure, Tertiary | Signal Transduction
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