Molecular Requirements for Actin-Based Lamella Formation in Drosophila S2 Cells

• Published in: The Journal of cell biology 2003-09, Vol.162 (6), p.1079-1088
• Main Authors: Rogers, Stephen L., Wiedemann, Ursula, Stuurman, Nico, Vale, Ronald D.
• Format: Article
• Language: English
• Subjects: Actin Cytoskeleton - metabolism; Actin Cytoskeleton - ultrastructure; Actin Depolymerizing Factors; Actin-Related Protein 2; Actins; Actins - antagonists & inhibitors; Actins - deficiency; Actins - genetics; Actins - metabolism; Adaptor Proteins, Signal Transducing; Animals; Caenorhabditis elegans Proteins - antagonists & inhibitors; Caenorhabditis elegans Proteins - genetics; Carrier Proteins - antagonists & inhibitors; Carrier Proteins - genetics; Carrier Proteins - metabolism; Cell adhesion & migration; Cell Cycle Proteins - antagonists & inhibitors; Cell Cycle Proteins - genetics; Cell Cycle Proteins - metabolism; Cell Line; Cell lines; Cell motility; Cell Movement - physiology; Cells; Cellular biology; Contractile Proteins; Cytoskeletal Proteins - antagonists & inhibitors; Cytoskeletal Proteins - genetics; Cytoskeletal Proteins - metabolism; Cytoskeleton; Delta cells; Destrin; Drosophila; Drosophila melanogaster; Drosophila Proteins - antagonists & inhibitors; Drosophila Proteins - deficiency; Drosophila Proteins - genetics; Drosophila Proteins - metabolism; Eukaryotic Cells - cytology; Eukaryotic Cells - metabolism; Insects; Microfilament Proteins - antagonists & inhibitors; Microfilament Proteins - deficiency; Microfilament Proteins - genetics; Microfilaments; Neurons; Profilins; Proteins; Pseudopodia - metabolism; Pseudopodia - ultrastructure; rac GTP-Binding Proteins - metabolism; RNA Interference; Scars
• ISSN: 0021-9525; 1540-8140
• DOI: 10.1083/jcb.200303023

Cell migration occurs through the protrusion of the actin-enriched lamella. Here, we investigated the effects of RNAi depletion of ∼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.