The bacterial virulence factors VopL and VopF nucleate actin from the pointed end

Burke, Thomas A.; Harker, Alyssa J; Domínguez, Roberto; Kovar, David R.

doi:10.1083/jcb.201608104

Cited by 24 publications

(49 citation statements)

References 50 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Finally, VopL and VopF are bacterial tandem WH2-domain-containing actin assembly factors of the Spire type, which support the colonization of infected epithelia by Vibrio parahaemolyticus (Liverman et al, 2007) and Vibrio cholerae (Tam et al, 2007), respectively. Although these proteins bind to both barbed and pointed actin filament ends (Pernier et al, 2013), nucleation was recently found to mostly occur from the pointed end (Burke et al, 2017).…”

Section: The Regulation Of Cell Edge Protrusions: Lamellipodia and Fimentioning

confidence: 99%

Actin assembly mechanisms at a glance

Rottner

Faix

Bogdan

et al. 2017

Journal of Cell Science

271

233

View full text Add to dashboard Cite

The actin cytoskeleton and associated motor proteins provide the driving forces for establishing the astonishing morphological diversity and dynamics of mammalian cells. Aside from functions in protruding and contracting cell membranes for motility, differentiation or cell division, the actin cytoskeleton provides forces to shape and move intracellular membranes of organelles and vesicles. To establish the many different actin assembly functions required in time and space, actin nucleators are targeted to specific subcellular compartments, thereby restricting the generation of specific actin filament structures to those sites. Recent research has revealed that targeting and activation of actin filament nucleators, elongators and myosin motors are tightly coordinated by conserved protein complexes to orchestrate force generation. In this Cell Science at a Glance article and the accompanying poster, we summarize and discuss the current knowledge on the corresponding protein complexes and their modes of action in actin nucleation, elongation and force generation.

show abstract

Section: The Regulation Of Cell Edge Protrusions: Lamellipodia and Fimentioning

confidence: 99%

Actin assembly mechanisms at a glance

Rottner

Faix

Bogdan

et al. 2017

Journal of Cell Science

271

233

View full text Add to dashboard Cite

show abstract

“…The crosslinker protein α-actinin-1, both in unlabeled form and tagged with mCherry, was purified as described in Ciobanasu et al (2014). Capping protein (CP) was purified as described (Burke et al, 2017), with minor modifications. From the elution buffer, the protein was dialyzed into phosphate-buffered saline (PBS) and labeled with SNAP-surface Alexa Fluor 647 following the manufacturer's protocol (New England Biolabs).…”

Section: Protein Preparationmentioning

confidence: 99%

Polarity sorting drives remodeling of actin-myosin networks

Wollrab

Belmonte

Baldauf

et al. 2018

Journal of Cell Science

View full text Add to dashboard Cite

Cytoskeletal networks of actin filaments and myosin motors drive many dynamic cell processes. A key characteristic of these networks is their contractility. Despite intense experimental and theoretical efforts, it is not clear what mechanism favors network contraction over expansion. Recent work points to a dominant role for the nonlinear mechanical response of actin filaments, which can withstand stretching but buckle upon compression. Here, we present an alternative mechanism. We study how interactions between actin and myosin-2 at the single-filament level translate into contraction at the network scale by performing time-lapse imaging on reconstituted quasi-2D networks mimicking the cell cortex. We observe myosin end-dwelling after it runs processively along actin filaments. This leads to transport and clustering of actin filament ends and the formation of transiently stable bipolar structures. Further, we show that myosin-driven polarity sorting produces polar actin asters, which act as contractile nodes that drive contraction in crosslinked networks. Computer simulations comparing the roles of the end-dwelling mechanism and a buckling-dependent mechanism show that the relative contribution of end-dwelling contraction increases as the network mesh-size decreases.

show abstract

“…Possibly, Spir only binds barbed ends in the presence of actin monomers as was described for N-Wasp (Co et al, 2007). This contrasts with VopL/F that primarily bind barbed ends of preformed filaments in the absence of free monomer (Burke et al, 2017). The first of Spir's tandem WH2 domains, WH2-A, is necessary to cap barbed ends.…”

Section: Spir Binds Both Ends Of Actin Filamentsmentioning

confidence: 94%

“…To our surprise, we found that SpirNT-beads were sufficient to bind both ends of actin filaments. There are conflicting reports regarding filament-end binding for two classes of tandem-WH2 nucleators: Spir and VopF/L (Liverman et al, 2007;Yu et al, 2011;Pernier et al, 2013Pernier et al, , 2016Burke et al, 2017). The N-termini of WH2 domains bind actin monomers between subdomains 1 and 3 of actin -the surface exposed at the barbed ends of filaments (Chereau et al, 2005;Hertzog et al, 2004).…”

Section: Spir Binds Both Ends Of Actin Filamentsmentioning

confidence: 99%

“…This is not unprecedented. Namgoong et al (Namgoong et al, 2011) and Burke et al (Burke et al, 2017) reported that VopL/F can interact with both ends of actin filaments, depending on the conditions. Earlier, we did not observe barbed-end binding by Spir when assayed by inhibition of depolymerization (Quinlan et al, 2005).…”

Section: Spir Binds Both Ends Of Actin Filamentsmentioning

confidence: 99%

See 1 more Smart Citation

Spire stimulates nucleation by Cappuccino and binds both ends of actin filaments

Bradley

Vizcarra

Bailey

et al. 2019

Preprint

View full text Add to dashboard Cite

Actin nucleators Cappuccino and Spire collaborate to build an actin mesh in oocytes. Data demonstrate that the collaboration leads to synergistic actin nucleation, as opposed to elongation.Further, Spire binds both ends of polar, actin filaments, resolving a long-outstanding question. AbstractAn actin mesh fills both mouse and fly oocytes. The meshes are built by a conserved mechanism and used to establish polarity. Two actin nucleators, Spire and Cappuccino, collaborate to build actin filaments that connect vesicles and the cortex. Direct interaction between Spire and Cappuccino is required for in vitro synergistic actin assembly; however, we understand little about why the interaction is necessary. To mimic the geometry of Spire and Cappuccino in vivo, we immobilized Spire on beads. We found that increased nucleation is a major part of synergy and that Spire alone binds both barbed-and pointed-ends of actin filaments. We identified Spire's barbed-end binding domain. Partial rescue of fertility by a loss-of-function mutant indicates that barbed-end binding is not necessary for Spire's in vivo function, but that it may play a role under normal circumstances. We propose that Spire stimulates nucleation by Cappuccino in a manner similar to the collaboration between APC and mDia1.

show abstract

The bacterial virulence factors VopL and VopF nucleate actin from the pointed end

Abstract: How the bacterial virulence factors VopL/F from Vibrio catalyze actin nucleation is unclear. Using multicolor TIRF microscopy imaging, Burke et al. find that VopL and VopF stimulate actin assembly via identical pointed-end nucleation mechanisms.

Cited by 24 publications

References 50 publications

Actin assembly mechanisms at a glance

Actin assembly mechanisms at a glance

Polarity sorting drives remodeling of actin-myosin networks

Spire stimulates nucleation by Cappuccino and binds both ends of actin filaments

Contact Info

Product

Resources

About