Control of Actin Filament Treadmilling in Cell Motility

Bugyi, Beáta; Carlier, Marie-France

doi:10.1146/annurev-biophys-051309-103849

Cited by 305 publications

(290 citation statements)

References 119 publications

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“…Phosphorylation of Cof-1 at serine 3 leads to loss of actin binding and severing activities and subsequently results in decreased cell motility (33). Actin remodeling and its impact on cell migration have an essential function in a variety of cellular processes such as cell movement, cell adhesion, and cytokinesis (38). Our data thus demonstrate a functional link between two major cellular functions, i.e.…”

Section: Discussionmentioning

confidence: 67%

Prolyl Hydroxylase Domain (PHD) 2 Affects Cell Migration and F-actin Formation via RhoA/Rho-associated Kinase-dependent Cofilin Phosphorylation

Vogel

Wottawa

Farhat

et al. 2010

Journal of Biological Chemistry

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Cells are responding to hypoxia via prolyl-4-hydroxylase domain (PHD) enzymes, which are responsible for oxygen-dependent hydroxylation of the hypoxia-inducible factor (HIF)-1␣ subunit. To gain further insight into PHD function, we generated knockdown cell models for the PHD2 isoform, which is the main isoform regulating HIF-1␣ hydroxylation and thus stability in normoxia. Induction of a PHD2 knockdown in tetracycline-inducible HeLa PHD2 knockdown cells resulted in increased F-actin formation as detected by phalloidin staining. A similar effect could be observed in the stably transfected PHD2 knockdown cell clones 1B6 and 3B7. F-actin is at least in part responsible for shaping cell morphology as well as regulating cell migration. Cell migration was impaired significantly as a consequence of PHD2 knockdown in a scratch assay. Mechanistically, PHD2 knockdown resulted in activation of the RhoA (Ras homolog gene family member A)/Rho-associated kinase pathway with subsequent phosphorylation of cofilin. Because cofilin phosphorylation impairs its actin-severing function, this may explain the F-actin phenotype, thereby providing a functional link between PHD2-dependent signaling and cell motility.

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Section: Discussionmentioning

confidence: 67%

Prolyl Hydroxylase Domain (PHD) 2 Affects Cell Migration and F-actin Formation via RhoA/Rho-associated Kinase-dependent Cofilin Phosphorylation

Vogel

Wottawa

Farhat

et al. 2010

Journal of Biological Chemistry

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“…A larger number of branches were observed to extend from newer mother filament segments, in part because they are more abundant than older segments in the network, and in part because branches preferentially form on newer vs. older segments (22,24). Both observations are inconsistent with proposals that Arp2/3 complex is incorporated only at the growing barbed ends of polymerizing filaments (29,30). Instead, the data strongly support a filament side-binding mechanism of Arp2/3 complex activation (Fig.…”

Section: Individual Arp2/3 Complexes Bind the Sides Of Preexisting Actinmentioning

confidence: 64%

Pathway of actin filament branch formation by Arp2/3 complex revealed by single-molecule imaging

Smith

Daugherty-Clarke

Goode

et al. 2013

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

101

137

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Actin filament nucleation by actin-related protein (Arp) 2/3 complex is a critical process in cell motility and endocytosis, yet key aspects of its mechanism are unknown due to a lack of real-time observations of Arp2/3 complex through the nucleation process. Triggered by the verprolin homology, central, and acidic (VCA) region of proteins in the Wiskott-Aldrich syndrome protein (WASp) family, Arp2/3 complex produces new (daughter) filaments as branches from the sides of preexisting (mother) filaments. We visualized individual fluorescently labeled Arp2/3 complexes dynamically interacting with and producing branches on growing actin filaments in vitro. Branch formation was strikingly inefficient, even in the presence of VCA: only ∼1% of filament-bound Arp2/3 complexes yielded a daughter filament. VCA acted at multiple steps, increasing both the association rate of Arp2/3 complexes with mother filament and the fraction of filament-bound complexes that nucleated a daughter. The results lead to a quantitative kinetic mechanism for branched actin assembly, revealing the steps that can be stimulated by additional cellular factors.

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“…actin | Ena/VASP | TIRF | cluster | formin T he highly coordinated spatial and temporal control of the assembly and disassembly of actin filaments is a major determinant of vital cellular processes such as endocytosis, cytokinesis, and cell migration (1)(2)(3)(4). Specific protein assemblies, composed of various actin-binding proteins, operate in these processes to nucleate and elongate new actin filaments, arrange them into complex 3D arrays, and subsequently recycle them to replenish the G-actin pool (5).…”

mentioning

confidence: 99%

Distinct VASP tetramers synergize in the processive elongation of individual actin filaments from clustered arrays

Brühmann

Ushakov

Winterhoff

et al. 2017

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

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Ena/VASP proteins act as actin polymerases that drive the processive elongation of filament barbed ends in membrane protrusions or at the surface of bacterial pathogens. Based on previous analyses of fast and slow elongating VASP proteins by in vitro total internal reflection fluorescence microscopy (TIRFM) and kinetic and thermodynamic measurements, we established a kinetic model of Ena/VASP-mediated actin filament elongation. At steady state, it entails that tetrameric VASP uses one of its arms to processively track growing filament barbed ends while three G-actin-binding sites (GABs) on other arms are available to recruit and deliver monomers to the filament tip, suggesting that VASP operates as a single tetramer in solution or when clustered on a surface, albeit processivity and resistance toward capping protein (CP) differ dramatically between both conditions. Here, we tested the model by variation of the oligomerization state and by increase of the number of GABs on individual polypeptide chains. In excellent agreement with model predictions, we show that in solution the rates of filament elongation directly correlate with the number of free GABs. Strikingly, however, irrespective of the oligomerization state or presence of additional GABs, filament elongation on a surface invariably proceeded with the same rate as with the VASP tetramer, demonstrating that adjacent VASP molecules synergize in the elongation of a single filament. Additionally, we reveal that actin ATP hydrolysis is not required for VASP-mediated filament assembly. Finally, we show evidence for the requirement of VASP to form tetramers and provide an amended model of processive VASPmediated actin assembly in clustered arrays.actin | Ena/VASP | TIRF | cluster | formin

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Control of Actin Filament Treadmilling in Cell Motility

Cited by 305 publications

References 119 publications

Prolyl Hydroxylase Domain (PHD) 2 Affects Cell Migration and F-actin Formation via RhoA/Rho-associated Kinase-dependent Cofilin Phosphorylation

Prolyl Hydroxylase Domain (PHD) 2 Affects Cell Migration and F-actin Formation via RhoA/Rho-associated Kinase-dependent Cofilin Phosphorylation

Pathway of actin filament branch formation by Arp2/3 complex revealed by single-molecule imaging

Distinct VASP tetramers synergize in the processive elongation of individual actin filaments from clustered arrays

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