Reorganization of the actin cytoskeleton allows cells to change shape and move in response to environmental cues. Polymerization of actin.is tightly regulated, and the cell maintains an arsenal of proteins to control when, where and how filaments grow. Arp2/3 complex is an assembly of seven proteins that nucleates the growth of new actin filaments in a signal-dependent manner. Nucleation promoting factors link Arp2/3 complex to upstream signals. They bind to Arp2/3 complex, recruit the first actin monomer for the new filament, and promote a activating conformational change in the complex. The goal of this proposal is to use x-ray crystallography to determine the structures of Arp2/3 complex with a bound nucleation promoting factor and with nucleation promoting factor plus actin monomer. These structures will provide a molecular basis for understanding how Arp2/3 complex nucleates the growth of new actin filaments. Furthermore, it will show how nucleation promoting factors activate the complex. This will provide a basis for a better understanding of cytoskeletal function in both normal and diseased states of the cell.
| Nolen, B J; Tomasevic, N; Russell, A et al. (2009) Characterization of two classes of small molecule inhibitors of Arp2/3 complex. Nature 460:1031-4 |
| Zencheck, Wendy D; Xiao, Hui; Nolen, Brad J et al. (2009) Nucleotide- and activator-dependent structural and dynamic changes of arp2/3 complex monitored by hydrogen/deuterium exchange and mass spectrometry. J Mol Biol 390:414-27 |
| Nolen, Brad J; Pollard, Thomas D (2008) Structure and biochemical properties of fission yeast Arp2/3 complex lacking the Arp2 subunit. J Biol Chem 283:26490-8 |
| Dalhaimer, Paul; Pollard, Thomas D; Nolen, Brad J (2008) Nucleotide-mediated conformational changes of monomeric actin and Arp3 studied by molecular dynamics simulations. J Mol Biol 376:166-83 |
| Nolen, Brad J; Pollard, Thomas D (2007) Insights into the influence of nucleotides on actin family proteins from seven structures of Arp2/3 complex. Mol Cell 26:449-57 |
