Arp2/3 complex activity in filopodia of spreading cells

Johnston, S.A., Bramble, J.P., Yeung, C.L., Mendes, P.M. and Machesky, L.M. (2008) Arp2/3 complex activity in filopodia of spreading cells. BMC Cell Biology, 9(1), p. 65. (doi: 10.1186/1471-2121-9-65)

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<p>Background: Cells use filopodia to explore their environment and to form new adhesion contacts for motility and spreading. The Arp2/3 complex has been implicated in lamellipodial actin assembly as a major nucleator of new actin filaments in branched networks. The interplay between filopodial and lamellipodial protrusions is an area of much interest as it is thought to be a key determinant of how cells make motility choices.</p> <p>Results: We find that Arp2/3 complex localises to dynamic puncta in filopodia as well as lamellipodia of spreading cells. Arp2/3 complex spots do not appear to depend on local adhesion or on microtubules for their localisation but their inclusion in filopodia or lamellipodia depends on the activity of the small GTPase Racl. Arp2/3 complex spots in filopodia are capable of incorporating monomeric actin, suggesting the presence of available filament barbed ends for polymerisation. Arp2/3 complex in filopodia co-localises with lamellipodial proteins such as capping protein and cortactin. The dynamics of Arp2/3 complex puncta suggests that they are moving bi-directionally along the length of filopodia and that they may be regions of lamellipodial activity within the filopodia.</p> <p>Conclusion: We suggest that filopodia of spreading cells have regions of lamellipodial activity and that this activity affects the morphology and movement of filopodia. Our work has implications for how we understand the interplay between lamellipodia and filopodia and for how actin networks are generated spatially in cells.</p>

Item Type:Articles
Glasgow Author(s) Enlighten ID:Machesky, Professor Laura
Authors: Johnston, S.A., Bramble, J.P., Yeung, C.L., Mendes, P.M., and Machesky, L.M.
College/School:College of Medical Veterinary and Life Sciences > Institute of Cancer Sciences
Journal Name:BMC Cell Biology
Publisher:BioMed Central
ISSN (Online):1471-2121
Published Online:09 December 2008
Copyright Holders:Copyright © 2008 The Authors
First Published:First published in BMC Cell Biology 9(1):65
Publisher Policy:Reproduced under a Creative Commons License

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