Dendritic organization of actin comet tails

Cameron, Lisa; Svitkina, Tatyana; Vignjević, Danijela; Theriot, Julie A.; Borisy, Gary G.

doi:10.1016/s0960-9822(01)00022-7

Cited by 170 publications

(160 citation statements)

References 25 publications

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“…3). This structure is known to be rich in actin, the major cytoskeletal constituent, and largely devoid of organelles (Steinmetz et al, 1997;Cameron et al, 2001). The front edge of the cell is continuously projected forward, while the rear is retracted.…”

Section: Actin Cytoskeletonmentioning

confidence: 99%

Polarization and Movement of Keratocytes: A Multiscale Modelling Approach

et al. 2006

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Section: Actin Cytoskeletonmentioning

confidence: 99%

Polarization and Movement of Keratocytes: A Multiscale Modelling Approach

et al. 2006

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“…Furthermore, several intracellular pathogens utilize Arp2/3 complex-based actin polymerization for intracellular movement (Frischknecht and Way, 2001) and cortactin is found in the`rocketing' actin tails of many (if not all) of these microbes, including Listeria ( Figure 3e,f), Shigella and Vaccinia (Zettl and Way, 2001). Pathogen-induced Arp2/3 actin networks are structurally similar to those found in lamellipodia, suggesting a similar mechanism of assembly (Cameron et al, 2001). While in the case of Vaccinia, cellular infection results in Src activation and cortactin tyrosine phosphorylation (Frischknecht et al, 1999a), it is not likely that cortactin tyrosine phosphorylation contributes to Vaccinia motility since tyrosine phosphorylation is restricted to the virus body and is not present in actin tails (Frischknecht et al, 1999b).…”

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confidence: 93%

Cortactin: coupling membrane dynamics to cortical actin assembly

2001

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Exposure of cells to a variety of external signals causes rapid changes in plasma membrane morphology. Plasma membrane dynamics, including membrane ru e and microspike formation, fusion or ®ssion of intracellular vesicles, and the spatial organization of transmembrane proteins, is directly controlled by the dynamic reorganization of the underlying actin cytoskeleton. Two members of the Rho family of small GTPases, Cdc42 and Rac, have been well established as mediators of extracellular signaling events that impact cortical actin organization. Actin-based signaling through Cdc42 and Rac ultimately results in activation of the actin-related protein (Arp) 2/3 complex, which promotes the formation of branched actin networks. In addition, the activity of both receptor and non-receptor protein tyrosine kinases along with numerous actin binding proteins works in concert with Arp2/3-mediated actin polymerization in regulating the formation of dynamic cortical actin-associated structures. In this review we discuss the structure and role of the cortical actin binding protein cortactin in Rho GTPase and tyrosine kinase signaling events, with the emphasis on the roles cortactin plays in tyrosine phosphorylation-based signal transduction, regulating cortical actin assembly, transmembrane receptor organization and membrane dynamics. We also consider how aberrant regulation of cortactin levels contributes to tumor cell invasion and metastasis. Oncogene (2001) 20, 6418 ± 6434.

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“…7 and 8 for review). It is now well established that the Arp2͞3 complex associates with Wiskott-Aldrich Syndrome protein (WASp) family proteins to create new filaments locally by branching them (9), thus generating the dendritic organization of the actin array (10,11). Because pure actin treadmilling is too slow to account for polymerization speed observed in these systems, this process has to be speeded up by regulatory proteins (8).…”

mentioning

confidence: 99%

Forces generated during actin-based propulsion: A direct measurement by micromanipulation

Marcy

Prost

Carlier

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

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Dynamic actin networks generate forces for numerous types of movements such as lamellipodia protrusion or the motion of endocytic vesicles. The actin-based propulsive movement of Listeria monocytogenes or of functionalized microspheres have been extensively used as model systems to identify the biochemical components that are necessary for actin-based motility. However, quantitative force measurements are required to elucidate the mechanism of force generation, which is still under debate. To directly probe the forces generated in the process of actin-based propulsion, we developed a micromanipulation experiment. A comet growing from a coated polystyrene bead is held by a micropipette while the bead is attached to a force probe, by using a specially designed ''flexible handle.'' This system allows us to apply both pulling and pushing external forces up to a few nanonewtons. By pulling the actin tail away from the bead at high speed, we estimate the elastic modulus of the gel and measure the force necessary to detach the tail from the bead. By applying a constant force in the range of ؊1.7 to 4.3 nN, the force-velocity relation is established. We find that the relation is linear for pulling forces and decays more weakly for pushing forces. This behavior is explained by using a dimensional elastic analysis.T he growth of a polymer against a barrier is a general mechanism for production of force in cell biology (1). Spatially controlled polymerization of actin is responsible for a large variety of changes in cell shape leading to cell movement, like the protrusion of the lamellipodium (2), or the intracellular propulsion of vesicles (3, 4) and pathogens (5, 6). Actin assembly in these processes is controlled by various proteins present in the cytoplasm, which have been identified over the last 10 years (see refs. 7 and 8 for review). It is now well established that the Arp2͞3 complex associates with Wiskott-Aldrich Syndrome protein (WASp) family proteins to create new filaments locally by branching them (9), thus generating the dendritic organization of the actin array (10, 11). Because pure actin treadmilling is too slow to account for polymerization speed observed in these systems, this process has to be speeded up by regulatory proteins (8). One experimental model that has been used widely for the identification of these proteins is the bacteria Listeria monocytogenes, which are propelled inside cells by actin polymerization. The minimal subset of proteins necessary and sufficient to reconstitute the Listeria movement has been identified (12). In addition to Arp2͞3 and actin, the regulatory proteins ADF͞ cofilin, profilin, and a capping protein are necessary to enhance the efficiency of treadmilling (13) and control the life time and average length of filaments (14, 15). The essential role of these proteins has been confirmed recently (16) in vivo by using a RNA interference strategy.Biomimetic systems are useful for analyzing the physical aspects of actin-based motility. Listeria movement can be mimicked by fun...

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Dendritic organization of actin comet tails

Cited by 170 publications

References 25 publications

Polarization and Movement of Keratocytes: A Multiscale Modelling Approach

Polarization and Movement of Keratocytes: A Multiscale Modelling Approach

Cortactin: coupling membrane dynamics to cortical actin assembly

Forces generated during actin-based propulsion: A direct measurement by micromanipulation

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