Molecular mechanism of Ena/VASP-mediated actin-filament elongation

Breitsprecher, Dennis; Kiesewetter, Antje K; Linkner, Joern; Vinzenz, Marlene; Stradal, Theresia E. B.; Small, J. Victor; Curth, Ute; Dickinson, Richard B.; Faix, Jan

doi:10.1038/emboj.2010.348

Cited by 144 publications

(187 citation statements)

References 57 publications

(117 reference statements)

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“…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). The only protein families known to date that actively drive the elongation of actin filaments by incorporation of actin monomers at growing barbed ends are formins and Ena/VASP proteins, albeit their modes of action are considerably different (6)(7)(8)(9).…”

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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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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“…15 These latter experiments directly validated the kinetic model for assembly proposed seven years earlier by Dickinson et al 11 It is now widely accepted that insertional polymerization by NPFs is how actin filaments are assembled within cell protrusions at the leading edge of a crawling tissue cell, if not every else as well in vivo. Hence, chemical engineering modeling and analysis revealed the essential mechanism of actin-filament assembly in vivo, which is widely relevant to a multitude of cellular functions, and helped turn the field to the actual mechanism long before direct experimental confirmation.…”

Section: ■ the Value Of Chemical Engineering "Thinking"mentioning

confidence: 68%

Chemical Engineering Principles in the Field of Cell Mechanics

Dickinson

Lele

2015

Ind. Eng. Chem. Res.

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The field of cell mechanics involves problems at the interface of mechanics, molecular transport, biochemical kinetics, thermodynamics, and cell biology. We argue that chemical engineering training is uniquely suited for fruitful research in the field by discussing three examples in the research area. Cell mechanics is already well-represented in many chemical engineering departments and promises to be a vibrant subarea in the profession.

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“…When expressed in melanoma cells, GFP-labelled MTSS1 showed a distinct localization at the cell periphery in addition to the diffuse cytoplasmic distribution previously reported in NIH3T3 cells 35 . A significant fraction of MTSS1 was localized at the front tips of the protruding lamellipodia, but not at the retracting side of the cell, and within filopodial plasma membrane protrusions enriched with Ena/VASP, a protein capping filopodia 40 (Fig. 6a), a distribution profile resembling that of actin filament assembly protein cofilin [40][41][42] .…”

Section: Identification Of Mtss1mentioning

confidence: 99%

“…A significant fraction of MTSS1 was localized at the front tips of the protruding lamellipodia, but not at the retracting side of the cell, and within filopodial plasma membrane protrusions enriched with Ena/VASP, a protein capping filopodia 40 (Fig. 6a), a distribution profile resembling that of actin filament assembly protein cofilin [40][41][42] . Unphosphorylated active cofilin associates with actin filaments in cell membrane protrusions where it drives actin dynamics by depolymerizing and severing ADP-bound actin filaments to regenerate the pool of In vivo metastasis 3/9 (33%) 7/9 (78%) actin monomers for new rounds of assembly at filament barbed ends 43 .…”

Section: Identification Of Mtss1mentioning

confidence: 99%

MTSS1 is a metastasis driver in a subset of human melanomas

et al. 2014

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In cancers with a highly altered genome, distinct genetic alterations drive subsets rather than the majority of individual tumours. Here we use a sequential search across human tumour samples for transcript outlier data points with associated gene copy number variations that correlate with patient's survival to identify genes with pro-invasive functionality. Employing loss and gain of function approaches in vitro and in vivo, we show that one such gene, MTSS1, promotes the ability of melanocytic cells to metastasize and engages actin dynamics via Rho-GTPases and cofilin in this process. Indeed, high MTSS1 expression defines a subgroup of primary melanomas with unfavourable prognosis. These data underscore the biological, clinical and potential therapeutic implications of molecular subsets within genetically complex cancers.

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Molecular mechanism of Ena/VASP-mediated actin-filament elongation

Cited by 144 publications

References 57 publications

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

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

Chemical Engineering Principles in the Field of Cell Mechanics

MTSS1 is a metastasis driver in a subset of human melanomas

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