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Citation
Humphreys, D., Liu, T., Davidson, A.C., Hume, P.J., Koronakis, V. (2012). The Drosophila Arf1 homologue Arf79F is essential for lamellipodium formation.  J. Cell Sci. 125(23): 5630--5635.
FlyBase ID
FBrf0220881
Publication Type
Research paper
Abstract

The 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 double-stranded 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.

PubMed ID
PubMed Central ID
PMC3575700 (PMC) (EuropePMC)
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    Language of Publication
    English
    Additional Languages of Abstract
    Parent Publication
    Publication Type
    Journal
    Abbreviation
    J. Cell Sci.
    Title
    Journal of Cell Science
    Publication Year
    1966-
    ISBN/ISSN
    0021-9533
    Data From Reference
    Genes (7)
    Physical Interactions (2)
    Cell Lines (1)