Actin-based motility

Theriot et al., 1992] Theriot, J. A., Mitchison, T. J., Tilney, L. G., and Portnoi, D. A. The rate of actin-based motility of intracellular Listeria monocytogenes equals the rate of actin polymerization. Nature. 357 (1992) 257-260... 

Smith, S.J. (1988). Neuronal cytomechanics The actin-based motility of growth cones. Science 242, 708-715. 

Egile C, Ixhsel TP, Laurent V, Li R, Pantaloni D, Sansonetti P J, Carlier MF Activation of the CDC42 effector N-WASP by the Shigella flexneri IcsA protein promotes actin nucleation by Arp2/3 complex and bacterial actin-based motility. J Cell Biol 1999 146 1319-1332. 

Suzuki T, Miki H, Takenawa T, Sasakawa C Neural Wiskott-Aldrich syndrome protein is implicated in the actin-based motility of Shigella flexneri. EMBO J 1998 17 2767-2776. 

Two examples where actin polymerization is observed in eukaryotes are in the bacterial pathogens Listeria monocytogenes and Shigella flexneri. The motion that the eukaryote pathogens exhibit is the actin based motility in the cytoplasm of their host. Actin polymerization is known to occur via an insertion polymerization mechanism. The movement is a result of site-directed tread-milling of the actin filaments. This type of movement is classified as a propulsive type motion. The driving force for actin pol)unerization as well as the next motor is the conversion of adenosine triphosphate (ATP) to adenosine diphosphate (ADP). ... 

D. Pantaloni, C. Le Clainche, and M. Carlier, Mechanism of actin-based motility, Science 292, 1502-1506 (2001). 

BASIC FEATURES OF THE ACTIN-BASED MOTOR COMPLEX. These experiments support the following model for Listeria actin-based motility. The Listeria surface protein ActA uses its oligoproline sequences (FEFPPPPTDE) to bind the host cell protein VASP. VASP in turn deploys its own larger set of GPPPPP sequences to bind profilin. 

Actin filaments grow rapidly within cells, and the clearest evidence of this rapid growth is the ability of the cell s leading edge to move at rates of 0.5 to 1 micrometer per second. Likewise, actin-based motility of Listeria and Shigella can attain rates of nearly 0.5 micrometers per second. Because microfilaments contain about 360 actin monomers per micrometer of length, a motility rate of 0.5 to 1 micrometer per second corresponds to an apparent first-order rate constant (/.e., / apparent = on [Actin-ATP]) of about 180-360 s . The bimolecular rate constant for actin-ATP addition to the barbed end has a nominal value of 2-3 X 10 s . Therefore, one can estimate... 

ACTIN ASSEMBLY KINETICS ACTIN-BASED MOTILITY MICROTUBULE ASSEMBLY KINETICS TREADMILLING... 

SHIFTED BINDING POLYMERIZATION QUASI-EQUIVALENCE ACTIN ASSEMBLY KINETICS ACTIN-BASED MOTILITY MICROTUBULE ASSEMBLY KINETICS IRREVERSIBLE POLYMERIZATION CRITICAL CONCENTRATION BIOCHEMICAL SELE-ASSEMBLY PROCESSIVITY... 

Muscle Proteins and Their Structures 1120 Box 19-C Actin-Based Motility and Bacterial... 

Bacteria also contain filamentous proteins that resemble F-actin and which may be utilized for cell-shape determination 301c Actin-based motility is used by some bacteria and other pathogens during invasion of host cells (Box 19-C). It is employed by sperm cells of Ascaris and of C. elegans, which crawl by an ameboid movement that utilizes treadmilling of filaments formed from a motile sperm protein, which does not... 

Compare the properties of actin in skeletal muscle and in nonmuscle cells. What is meant by "treadmilling " What is "actin-based motility "... 

Carlier, M.-F., Le Clainche, C., Wiesner, S., and Pantaloni, D. (2002). Actin-based motility From Molecules to movement. Bioessays 25, 336-345. 

Loisel, T. P., Boujemaa, R., Pantaloni, D., and Carlier, M. F. (1999). Reconstitution of actin-based motility of Listeria and Shigella using pure proteins. Nature 401, 13-16. 

Reinhard M, Jarchau T, Walter U (2001) Actin-based motility stop and go with Ena/VASP proteins. 

Myosins are a large family of motor proteins they are powered by the hydrolysis of ATP and convert chemical energy into mechanical work. They are responsible for actin-based motility. Most myosin molecules are composed of a head, a neck and a tail domain. 

Gerisch G, Noegcl AA, Schleicher M. Genetic alteration of proteins in actin-based motility systems. Annu Rev Physiol 1991 53 607-28. 

In all the actin-based motility systems, and especially skeletal, cardiac and smooth muscle, contraction is initiated primarily by an increase in cytoplasmic [Ca +]. However, the major differences in histology and function of these muscle types are associated with great variety in how contraction is controlled. Smooth muscle especially differs from the model presented for skeletal muscle. Skeletal muscle is activated by Ca + released from SR in response to sarcolemmal action potentials. Ca + exerts its effect by binding to troponin on the thin filaments, which reverses the tropomyosin inhibition of cross-bridge formation. 

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