High-resolution X-ray structure of the trimeric Scar/WAVE-complex precursor Brk1.

Linkner, Joern; Witte, Gregor; Stradal, Theresia; Curth, Ute; Faix, Jan

dc.contributor.author	Linkner, Joern
dc.contributor.author	Witte, Gregor
dc.contributor.author	Stradal, Theresia
dc.contributor.author	Curth, Ute
dc.contributor.author	Faix, Jan
dc.date.accessioned	2011-12-07T15:36:57Z
dc.date.available	2011-12-07T15:36:57Z
dc.date.issued	2011
dc.identifier.citation	High-resolution X-ray structure of the trimeric Scar/WAVE-complex precursor Brk1. 2011, 6 (6):e21327 PLoS ONE	en
dc.identifier.issn	1932-6203
dc.identifier.pmid	21701600
dc.identifier.doi	10.1371/journal.pone.0021327
dc.identifier.uri	http://hdl.handle.net/10033/196329
dc.description.abstract	The Scar/WAVE-complex links upstream Rho-GTPase signaling to the activation of the conserved Arp2/3-complex. Scar/WAVE-induced and Arp2/3-complex-mediated actin nucleation is crucial for actin assembly in protruding lamellipodia to drive cell migration. The heteropentameric Scar/WAVE-complex is composed of Scar/WAVE, Abi, Nap, Pir and a small polypeptide Brk1/HSPC300, and recent work suggested that free Brk1 serves as a homooligomeric precursor in the assembly of this complex. Here we characterized the Brk1 trimer from Dictyostelium by analytical ultracentrifugation and gelfiltration. We show for the first time its dissociation at concentrations in the nanomolar range as well as an exchange of subunits within different DdBrk1 containing complexes. Moreover, we determined the three-dimensional structure of DdBrk1 at 1.5 Å resolution by X-ray crystallography. Three chains of DdBrk1 are associated with each other forming a parallel triple coiled-coil bundle. Notably, this structure is highly similar to the heterotrimeric α-helical bundle of HSPC300/WAVE1/Abi2 within the human Scar/WAVE-complex. This finding, together with the fact that Brk1 is collectively sandwiched by the remaining subunits and also constitutes the main subunit connecting the triple-coil domain of the HSPC300/WAVE1/Abi2/ heterotrimer to Sra1(Pir1), implies a critical function of this subunit in the assembly process of the entire Scar/WAVE-complex.
dc.language.iso	en	en
dc.subject.mesh	Blotting, Western	en
dc.subject.mesh	Chromatography, Gel	en
dc.subject.mesh	Crystallography, X-Ray	en
dc.subject.mesh	Dictyostelium	en
dc.subject.mesh	Protozoan Proteins	en
dc.subject.mesh	Ultracentrifugation	en
dc.subject.mesh	Wiskott-Aldrich Syndrome Protein Family	en
dc.title	High-resolution X-ray structure of the trimeric Scar/WAVE-complex precursor Brk1.	en
dc.type	Article	en
dc.contributor.department	Institute for Biophysical Chemistry, Hannover Medical School, Hannover, Germany.	en
dc.identifier.journal	PloS one	en
refterms.dateFOA	2018-06-12T22:09:08Z
html.description.abstract	The Scar/WAVE-complex links upstream Rho-GTPase signaling to the activation of the conserved Arp2/3-complex. Scar/WAVE-induced and Arp2/3-complex-mediated actin nucleation is crucial for actin assembly in protruding lamellipodia to drive cell migration. The heteropentameric Scar/WAVE-complex is composed of Scar/WAVE, Abi, Nap, Pir and a small polypeptide Brk1/HSPC300, and recent work suggested that free Brk1 serves as a homooligomeric precursor in the assembly of this complex. Here we characterized the Brk1 trimer from Dictyostelium by analytical ultracentrifugation and gelfiltration. We show for the first time its dissociation at concentrations in the nanomolar range as well as an exchange of subunits within different DdBrk1 containing complexes. Moreover, we determined the three-dimensional structure of DdBrk1 at 1.5 Å resolution by X-ray crystallography. Three chains of DdBrk1 are associated with each other forming a parallel triple coiled-coil bundle. Notably, this structure is highly similar to the heterotrimeric α-helical bundle of HSPC300/WAVE1/Abi2 within the human Scar/WAVE-complex. This finding, together with the fact that Brk1 is collectively sandwiched by the remaining subunits and also constitutes the main subunit connecting the triple-coil domain of the HSPC300/WAVE1/Abi2/ heterotrimer to Sra1(Pir1), implies a critical function of this subunit in the assembly process of the entire Scar/WAVE-complex.