title: Molecular requirements for actin-based lamella formation in Drosophila S2 cells.
abstract: Cell migration occurs through the protrusion of the actin-enriched lamella. Here, we investigated the effects of RNAi depletion of approximately 90 proteins implicated in actin function on lamella formation in Drosophila S2 cells. Similar to in vitro reconstitution studies of actin-based Listeria movement, we find that lamellae formation requires a relatively small set of proteins that participate in actin nucleation (Arp2/3 and SCAR), barbed end capping (capping protein), filament depolymerization (cofilin and Aip1), and actin monomer binding (profilin and cyclase-associated protein). Lamellae are initiated by parallel and partially redundant signaling pathways involving Rac GTPases and the adaptor protein Nck, which stimulate SCAR, an Arp2/3 activator. We also show that RNAi of three proteins (kette, Abi, and Sra-1) known to copurify with and inhibit SCAR in vitro leads to SCAR degradation, revealing a novel function of this protein complex in SCAR stability. Our results have identified an essential set of proteins involved in actin dynamics during lamella formation in Drosophila S2 cells.
authors.affiliation: Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94107, USA.
authors.forename: Stephen L
authors.initials: SL
authors.lastname: Rogers
authors.forename: Ursula
authors.initials: U
authors.lastname: Wiedemann
authors.forename: Nico
authors.initials: N
authors.lastname: Stuurman
authors.forename: Ronald D
authors.initials: RD
authors.lastname: Vale
mesh_terms: D008841:Actin Cytoskeleton / Q000378:metabolism* / Q000648:ultrastructure; D051339:Actin Depolymerizing Factors; D051377:Actin-Related Protein 2; D000199:Actins / Q000037:antagonists & inhibitors / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D029742:Caenorhabditis elegans Proteins / Q000037:antagonists & inhibitors / Q000235:genetics; D002352:Carrier Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D002460:Cell Line; D002465:Cell Movement / Q000502:physiology*; D003285:Contractile Proteins; D003598:Cytoskeletal Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D051345:Destrin; D029721:Drosophila Proteins / Q000037:antagonists & inhibitors / Q000172:deficiency / Q000235:genetics / Q000378:metabolism; D004331:Drosophila melanogaster; D005057:Eukaryotic Cells / Q000166:cytology / Q000378:metabolism*; D008840:Microfilament Proteins / Q000037:antagonists & inhibitors / Q000172:deficiency / Q000235:genetics; D051304:Profilins; D011554:Pseudopodia / Q000378:metabolism* / Q000648:ultrastructure; D034622:RNA Interference; D020744:rac GTP-Binding Proteins / Q000378:metabolism
chemical_list: C121808:Abi protein, Drosophila; D051339:Actin Depolymerizing Factors; D051377:Actin-Related Protein 2; D000199:Actins; D048868:Adaptor Proteins, Signal Transducing; C489549:CAP1 protein, human; D029742:Caenorhabditis elegans Proteins; C410502:Capt protein, Drosophila; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D003285:Contractile Proteins; D003598:Cytoskeletal Proteins; D051345:Destrin; D029721:Drosophila Proteins; D008840:Microfilament Proteins; D051304:Profilins; C449671:SCAR protein, Drosophila; C484666:Sra-1 protein, Drosophila; C115237:actin interacting protein 1; C476568:arx-2 protein, C elegans; C495737:chic protein, Drosophila; D020744:rac GTP-Binding Proteins