Rac1 and Rac2 differentially regulate actin free barbed end formation downstream of the fMLP receptor
| Autor: | Chun Xiang Sun, Michael Glogauer, Marco A. O. Magalhaes |
|---|---|
| Rok vydání: | 2007 |
| Předmět: |
rac1 GTP-Binding Protein
Neutrophils Arp2/3 complex macromolecular substances Actin-Related Protein 2-3 Complex 03 medical and health sciences Actin remodeling of neurons Mice 0302 clinical medicine Report Animals Actin-binding protein Pseudopodia Phosphorylation Research Articles 030304 developmental biology 0303 health sciences biology Chemotaxis Neuropeptides Actin remodeling Cell Biology Cofilin Actin cytoskeleton Receptors Formyl Peptide Actins Cell biology rac GTP-Binding Proteins Actin Cytoskeleton Protein Transport Actin Depolymerizing Factors 030220 oncology & carcinogenesis biology.protein MDia1 Subcellular Fractions |
| Zdroj: | The Journal of Cell Biology |
| ISSN: | 0021-9525 |
| Popis: | Actin assembly at the leading edge of migrating cells depends on the availability of high-affinity free barbed ends (FBE) that drive actin filament elongation and subsequent membrane protrusion. We investigated the specific mechanisms through which the Rac1 and Rac2 small guanosine triphosphatases (GTPases) generate free barbed ends in neutrophils. Using neutrophils lacking either Rac1 or Rac2 and a neutrophil permeabilization model that maintains receptor signaling to the actin cytoskeleton, we assessed the mechanisms through which these two small GTPases mediate FBE generation downstream of the formyl-methionyl-leucyl-phenylalanine receptor. We demonstrate here that uncapping of existing barbed ends is mediated through Rac1, whereas cofilin- and ARP2/3-mediated FBE generation are regulated through Rac2. This unique combination of experimental tools has allowed us to identify the relative roles of uncapping (15%), cofilin severing (10%), and ARP2/3 de novo nucleation (75%) in FBE generation and the respective roles played by Rac1 and Rac2 in mediating actin dynamics. |
| Databáze: | OpenAIRE |
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