3P53

Structure of fascin

Summary for 3P53

• Entry DOI: 10.2210/pdb3p53/pdb
• Descriptor: Fascin, GLYCEROL, DODECAETHYLENE GLYCOL, ... (6 entities in total)
• Functional Keywords: beta-trefoil domain, structural protein
• Biological source: Homo sapiens (human)
• Cellular location: Cytoplasm, cytoskeleton: Q16658
• Total number of polymer chains: 2
• Total formula weight: 112331.24

Authors

Jansen, S.,Dominguez, R. (deposition date: 2010-10-07, release date: 2011-06-29, Last modification date: 2024-02-21)

Primary citation

Jansen, S.,Collins, A.,Yang, C.,Rebowski, G.,Svitkina, T.,Dominguez, R.
Mechanism of actin filament bundling by fascin.
J.Biol.Chem., 286:30087-30096, 2011

PubMed Abstract: Fascin is the main actin filament bundling protein in filopodia. Because of the important role filopodia play in cell migration, fascin is emerging as a major target for cancer drug discovery. However, an understanding of the mechanism of bundle formation by fascin is critically lacking. Fascin consists of four β-trefoil domains. Here, we show that fascin contains two major actin-binding sites, coinciding with regions of high sequence conservation in β-trefoil domains 1 and 3. The site in β-trefoil-1 is located near the binding site of the fascin inhibitor macroketone and comprises residue Ser-39, whose phosphorylation by protein kinase C down-regulates actin bundling and formation of filopodia. The site in β-trefoil-3 is related by pseudo-2-fold symmetry to that in β-trefoil-1. The two sites are ∼5 nm apart, resulting in a distance between actin filaments in the bundle of ∼8.1 nm. Residue mutations in both sites disrupt bundle formation in vitro as assessed by co-sedimentation with actin and electron microscopy and severely impair formation of filopodia in cells as determined by rescue experiments in fascin-depleted cells. Mutations of other areas of the fascin surface also affect actin bundling and formation of filopodia albeit to a lesser extent, suggesting that, in addition to the two major actin-binding sites, fascin makes secondary contacts with other filaments in the bundle. In a high resolution crystal structure of fascin, molecules of glycerol and polyethylene glycol are bound in pockets located within the two major actin-binding sites. These molecules could guide the rational design of new anticancer fascin inhibitors.

PubMed: 21685497
DOI: 10.1074/jbc.M111.251439

Experimental method

X-RAY DIFFRACTION (2 Å)