Abi, Sra1, and Kette Control the Stability and Localization of SCAR/WAVE to Regulate the Formation of Actin-Based Protrusions

Kunda, Patricia; Craig, Gavin; Domínguez, Verónica; Baum, Buzz

doi:10.1016/j.cub.2003.10.005

Cited by 331 publications

(406 citation statements)

References 35 publications

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“…Rac1-silencing also impaired lamellipodium formation in ,59% of cells (Fig. 1C,D), a much milder phenotype than in WRC-silenced cells as previously reported (D'Ambrosio and Vale, 2010;Kunda et al, 2003;Rohn et al, 2011). In Arf79F-silenced cells, lamellipodia were abolished in ,87% of cells showing that Arf79F is critical for lamellipodium formation (Fig.…”

Section: Resultssupporting

confidence: 85%

“…1C,D) but Sra1 dsRNAi (supplementary material Fig. S1B) impaired lamellipodia in ,93% of cells giving rise to a characteristic ''starfish'' phenotype (Kunda et al, 2003), typified by multiple thin extensions and disruption of cortical actin filaments (Fig. 1C,D).…”

Section: Resultsmentioning

confidence: 95%

“…In Drosophila cells however, each Arf class is represented by a single isoform, namely Arf79F (Class 1), Arf102F (Class 2) and Arf51F (Class 3). Therefore, to bypass this additional layer of complexity, we used Drosophila S2R+ cells where only single WRC subunits (SCAR, Sra1, Kette/Nap1, Abi and HSPC300) are encoded, all of which are required for lamellipodium formation, which is very prominent in this cell type (Kunda et al, 2003;Rogers et al, 2003;Zallen et al, 2002). We first examined whether the Drosophila Arf1 homologue Arf79F localised at lamellipodia of S2R+ cells by immunofluorescence using antibodies against human Arf1 and Drosophila Sra1 (Fig.…”

Section: Resultsmentioning

confidence: 99%

“…The protrusive force is supplied by polymerisation of actin filaments initiated via the ubiquitous Arp2/3 complex which is activated by nucleation promoting factors (NPFs) (Campellone and Welch, 2010). In mammalian and Drosophila cells, the critical NPF underlying lamellipodium formation is the WRC {WAVE [WASP (WiskottAldrich syndrome protein)-family verprolin-homologous protein] regulatory complex}, which is thought to be activated at the plasma membrane by the Rho GTPase Rac1 (Kunda et al, 2003;Miki et al, 1998). Purified mammalian WRC is inactive, but can be activated in buffer by high concentrations of Rac1 (Ismail et al, 2009).…”

Section: Introductionmentioning

confidence: 99%

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The Drosophila Arf1 homologue Arf79F is essential for lamellipodium formation

Humphreys

Liu

Davidson

et al. 2012

Journal of Cell Science

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SummaryThe WAVE regulatory complex (WRC) drives the polymerisation of actin filaments located beneath the plasma membrane to generate lamellipodia that are pivotal to cell architecture and movement. By reconstituting WRC-dependent actin assembly at the membrane, we recently discovered that several classes of Arf family GTPases directly recruit and activate WRC in cell extracts, and that Arf cooperates with Rac1 to trigger actin polymerisation. Here, we demonstrate that the Class 1 Arf1 homologue Arf79F colocalises with the WRC at dynamic lamellipodia. We report that Arf79F is required for lamellipodium formation in Drosophila S2R+ cells, which only express one Arf isoform for each class. Impeding Arf function either by dominant-negative Arf expression or by Arf doublestranded RNA interference (dsRNAi)-mediated knockdown uncovered that Arf-dependent lamellipodium formation was specific to Arf79F, establishing that Class 1 Arfs, but not Class 2 or Class 3 Arfs, are crucial for lamellipodia. Lamellipodium formation in Arf79F-silenced cells was restored by expressing mammalian Arf1, but not by constitutively active Rac1, showing that Arf79F does not act via Rac1. Abolition of lamellipodium formation in Arf79F-silenced cells was not due to Golgi disruption. Blocking Arf79F activation with guanine nucleotide exchange factor inhibitors impaired WRC localisation to the plasma membrane and concomitant generation of lamellipodia. Our data indicate that the Class I Arf GTPase is a central component in WRC-driven lamellipodium formation.

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Section: Resultssupporting

confidence: 85%

Section: Resultsmentioning

confidence: 95%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

The Drosophila Arf1 homologue Arf79F is essential for lamellipodium formation

Humphreys

Liu

Davidson

et al. 2012

Journal of Cell Science

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“…10 The majority of WAVE2 in the cell is complexed with Abl-interactor-1 (Abi1), Nck-associated protein-1 (Nap1), a small protein HSPC300, and p53-inducible protein-121 (PIR121)/Sra1. 11 Although the activity of the WAVE2 complex has yet to be examined, it is considered to be strictly regulated by other molecules that act as different signaling inputs regulating actin dynamics.…”

mentioning

confidence: 99%

Coexpression of Arp2 and WAVE2 predicts poor outcome in invasive breast carcinoma

2007

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Breast carcinoma with a high histologic grade is highly invasive and metastatic. One reason for its irregular morphology is the formation of excessive protrusions due to assemblages of branched actin filament networks. In mammalian cells, the actin-related protein 2 and 3 (Arp2/3) complex initiates actin assembly to form lamellipodial protrusions by binding to the Wiskott-Aldrich syndrome (WASP)/WASP family verprolinehomologous protein2 (WAVE2), a member of the WASP protein family. In this study, the localization Arp2 and WAVE2 in breast carcinoma was investigated to clarify whether coexpression of the two proteins is associated with histologic grade or patient outcome. Immunohistochemical staining of Arp2 and WAVE2 was performed on mirror specimens of 197 breast carcinomas, and the association between coexpression of the two proteins and clinicopathologic factors was examined. Kaplan-Meier disease-free survival and overall survival curves were analyzed to determine the prognostic significance of Arp2 and WAVE2 coexpression in breast carcinoma. Coexpression of Arp2 and WAVE2 was detected in 64 (36%) of 179 invasive ductal carcinomas and in 2 (11%) of 18 ductal carcinomas in situ, but was not detected in any adjacent non-cancerous tissue. The proportion of cancer cells expressing both Arp2 and WAVE2 was significantly higher in cases with high histologic grade (Po0.0001), and cases with lymph node metastasis (P ¼ 0.0150). The patients whose cancer cells showed such coexpression had shorter disease-free (P ¼ 0.0002) and overall survival (P ¼ 0.0122) than patients whose cancer cells expressed only one or none of Arp2 and WAVE2. Multivariate Cox regression analysis revealed that coexpression of Arp2 and WAVE2 is an independent factor for both tumor recurrence (P ¼ 0.0308) and death (P ¼ 0.0455). These results indicate that coexpression of Arp2 and WAVE2 is a significant prognostic factor that is closely associated with aggressive morphology of invasive ductal carcinoma of the breast.

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dAsap regulates cellular protrusions via an Arf6‐dependent actin regulatory pathway in S2R+ cells

Kushwaha,

Mallik,

Bisht

et al. 2024

FEBS Letters

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Membrane protrusions are fundamental to cellular functions like migration, adhesion, and communication and depend upon dynamic reorganization of the cytoskeleton. GAP‐dependent GTP hydrolysis of Arf proteins regulates actin‐dependent membrane remodeling. Here, we show that dAsap regulates membrane protrusions in S2R+ cells by a mechanism that critically relies on its ArfGAP domain and relocalization of actin regulators, SCAR, and Ena. While our data reinforce the preference of dAsap for Arf1 GTP hydrolysis in vitro, we demonstrate that induction of membrane protrusions in S2R+ cells depends on Arf6 inactivation. This study furthers our understanding of how dAsap‐dependent GTP hydrolysis maintains a balance between active and inactive states of Arf6 to regulate cell shape.

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Abi, Sra1, and Kette Control the Stability and Localization of SCAR/WAVE to Regulate the Formation of Actin-Based Protrusions

Cited by 331 publications

References 35 publications

The Drosophila Arf1 homologue Arf79F is essential for lamellipodium formation

The Drosophila Arf1 homologue Arf79F is essential for lamellipodium formation

Coexpression of Arp2 and WAVE2 predicts poor outcome in invasive breast carcinoma

dAsap regulates cellular protrusions via an Arf6‐dependent actin regulatory pathway in S2R+ cells

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