0000000000511768
AUTHOR
David A. Calderwood
Structure of three tandem filamin domains reveals auto-inhibition of ligand binding
Human filamins are large actin-crosslinking proteins composed of an N-terminal actin-binding domain followed by 24 Ig-like domains (IgFLNs), which interact with numerous transmembrane receptors and cytosolic signaling proteins. Here we report the 2.5 A resolution structure of a three-domain fragment of human filamin A (IgFLNa19-21). The structure reveals an unexpected domain arrangement, with IgFLNa20 partially unfolded bringing IgFLNa21 into close proximity to IgFLNa19. Notably the N-terminus of IgFLNa20 forms a beta-strand that associates with the CD face of IgFLNa21 and occupies the binding site for integrin adhesion receptors. Disruption of this IgFLNa20-IgFLNa21 interaction enhances fi…
The molecular basis of filamin binding to integrins and competition with talin.
The ability of adhesion receptors to transmit biochemical signals and mechanical force across cell membranes depends on interactions with the actin cytoskeleton. Filamins are large, actin-crosslinking proteins that connect multiple transmembrane and signaling proteins to the cytoskeleton. Here, we describe the high-resolution structure of an interface between filamin A and an integrin adhesion receptor. When bound, the integrin beta cytoplasmic tail forms an extended beta strand that interacts with beta strands C and D of the filamin immunoglobulin-like domain (IgFLN) 21. This interface is common to many integrins, and we suggest it is a prototype for other IgFLN domain interactions. Notabl…
Structural basis of the migfilin-filamin interaction and competition with integrin beta tails.
A link between sites of cell adhesion and the cytoskeleton is essential for regulation of cell shape, motility, and signaling. Migfilin is a recently identified adaptor protein that localizes at cell-cell and cell-extracellular matrix adhesion sites, where it is thought to provide a link to the cytoskeleton by interacting with the actin cross-linking protein filamin. Here we have used x-ray crystallography, NMR spectroscopy, and protein-protein interaction studies to investigate the molecular basis of migfilin binding to filamin. We report that the N-terminal portion of migfilin can bind all three human filamins (FLNa, -b, or -c) and that there are multiple migfilin-binding sites in FLNa. H…