Control of actin assembly and disassembly at filament ends

Department of Cell Biology, Washington University, Box 8228, St Louis, MO 631110, USA.
Current Opinion in Cell Biology (Impact Factor: 8.74). 03/2000; 12(1):97-103. DOI: 10.1016/S0955-0674(99)00062-9
Source: PubMed

ABSTRACT The most important discovery in the field is that the Arp2/3 complex nucleates assembly of actin filaments with free barbed ends. Arp2/3 also binds the sides of actin filaments to create a branched network. Arp2/3's nucleation activity is stimulated by WASP family proteins, some of which mediate signaling from small G-proteins. Listeria movement caused by actin polymerization can be reconstituted in vitro using purified proteins: Arp2/3 complex, capping protein, actin depolymerizing factor/cofilin, and actin. actin depolymerizing factor/cofilin increases the rate at which actin subunits leave pointed ends, and capping protein caps barbed ends.

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Available from: Dorothy A Schafer, Feb 05, 2014
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    • "Cell migration requires a number of changes, e.g. the reorganization of the actin cytoskeleton (Mogilner and Edelstein-Keshet, 2002), changes in cell shape and in activity of various cytokines and growth factors. On the other hand, proper organization of the cell cytoskeleton is essential for a number of fundamental processes in cells including proliferation, migration, differentiation, signal transmission or regeneration (Cooper and Schafer, 2000; Mogilner and Edelstein-Keshet, 2002; Pollard and Borisy, 2003). There are several reports indicating significant disruption of the hepatocyte actin cytoskeleton caused by MC-LR (Runnegar et al., 1995; Toivola and Eriksson, 1999; Batista et al., 2003). "
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    • "The leading edge of a migrating cell shows particularly dynamic construction and destruction of the actin network , facilitated by a variety of proteins (for review, see Cooper and Schafer 2000; Pollard and Borisy 2003). For example, cofilin severs actin filaments, which can enhance filament depolymerization but also creates new barbed ends, and thus stimulates actin polymerization when monomer concentration is high (Ichetovkin et al. 2002; Adrianantoandro and Pollard 2006). "
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    • "In addition to spectrin and actin, the acrosome contained other cytoskeleton effectors, such as myosin, a protein involved in many types of cell movement and in the migration of various components within the cell (Alberts et al, 2003); calmodulin, known to control a great number of processes, such as fertilization, contraction , motility, secretion, neurotransmission, and metabolism (Stevens, 1982; Tomlinson et al, 1984); and gelsolin, which cuts actin filaments and binds to 1 end of these filaments, blocking the addition of more actin monomers (Cooper and Schafer, 2000). When activated, gelsolin might disrupt the acrosomal matrix's releasing its enzymes (Cooper and Schafer, 2000). The dynamics of actin/myosin complexes are controlled by calmodulin as follows: the calcium/calmodulin complex activates the MLCK binding near the carboxyl terminal domain (Vetter and Leclerc, 2003). "
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