3UE5

ECP-cleaved Actin in complex with Spir domain D

Summary for 3UE5

• Entry DOI: 10.2210/pdb3ue5/pdb
• Descriptor: Actin, alpha skeletal muscle, Protein spire, CALCIUM ION, ... (6 entities in total)
• Functional Keywords: contractile protein, contractile protein-transport protein complex, contractile protein/transport protein
• Biological source: Drosophila melanogaster (Fruit fly); More
• Cellular location: Cytoplasm, cytoskeleton: P68135 Q9U1K1
• Total number of polymer chains: 2
• Total formula weight: 49801.36

Authors

Chen, C.,Phillips, M.,Sawaya, M.R.,Ralston, C.Y.,Quinlan, M.E. (deposition date: 2011-10-28, release date: 2012-02-15, Last modification date: 2012-04-11)

Primary citation

Chen, C.K.,Sawaya, M.R.,Phillips, M.L.,Reisler, E.,Quinlan, M.E.
Multiple Forms of Spire-Actin Complexes and their Functional Consequences.
J.Biol.Chem., 287:10684-10692, 2012

PubMed Abstract: Spire is a WH2 domain-containing actin nucleator essential for establishing an actin mesh during oogenesis. In vitro, in addition to nucleating filaments, Spire can sever them and sequester actin monomers. Understanding how Spire is capable of these disparate functions and which are physiologically relevant is an important goal. To study severing, we examined the effect of Drosophila Spire on preformed filaments in bulk and single filament assays. We observed rapid depolymerization of actin filaments by Spire, which we conclude is largely due to its sequestration activity and enhanced by its weak severing activity. We also studied the solution and crystal structures of Spire-actin complexes. We find structural and functional differences between constructs containing four WH2 domains (Spir-ABCD) and two WH2 domains (Spir-CD) that may provide insight into the mechanisms of nucleation and sequestration. Intriguingly, we observed lateral interactions between actin monomers associated with Spir-ABCD, suggesting that the structures built by these four tandem WH2 domains are more complex than originally imagined. Finally, we propose that Spire-actin mixtures contain both nuclei and sequestration structures.

PubMed: 22334675
DOI: 10.1074/jbc.M111.317792

Experimental method

X-RAY DIFFRACTION (2.76 Å)