2LNK image
Entry Detail
PDB ID:
2LNK
Title:
Solution structure of Ca-bound S100A4 in complex with non-muscle myosin IIA
Biological Source:
Source Organism:
Host Organism:
PDB Version:
Deposition Date:
2011-12-30
Release Date:
2012-04-25
Method Details:
Experimental Method:
Conformers Calculated:
200
Conformers Submitted:
20
Selection Criteria:
structures with the lowest energy
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:Protein S100-A4
Chain IDs:B (auth: A), C (auth: B)
Chain Length:113
Number of Molecules:2
Biological Source:Homo sapiens
Polymer Type:polypeptide(L)
Description:Myosin heavy chain, non-muscle IIa
Chain IDs:A (auth: C)
Chain Length:39
Number of Molecules:1
Biological Source:Homo sapiens
Ligand Molecules
Primary Citation
Asymmetric Mode of Ca(2+)-S100A4 Interaction with Nonmuscle Myosin IIA Generates Nanomolar Affinity Required for Filament Remodeling.
Structure 20 654 666 (2012)
PMID: 22483112 DOI: 10.1016/j.str.2012.02.002

Abstact

Filament assembly of nonmuscle myosin IIA (NMIIA) is selectively regulated by the small Ca²⁺-binding protein, S100A4, which causes enhanced cell migration and metastasis in certain cancers. Our NMR structure shows that an S100A4 dimer binds to a single myosin heavy chain in an asymmetrical configuration. NMIIA in the complex forms a continuous helix that stretches across the surface of S100A4 and engages the Ca²⁺-dependent binding sites of each subunit in the dimer. Synergy between these sites leads to a very tight association (K(D) ∼1 nM) that is unique in the S100 family. Single-residue mutations that remove this synergy weaken binding and ameliorate the effects of S100A4 on NMIIA filament assembly and cell spreading in A431 human epithelial carcinoma cells. We propose a model for NMIIA filament disassembly by S100A4 in which initial binding to the unstructured NMIIA tail initiates unzipping of the coiled coil and disruption of filament packing.

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Primary Citation of related structures