Structure of Ca2+-bound S100A4 and its interaction with peptides derived from nonmuscle myosin-IIA

Vladimir N. Malashkevich, Kristen M. Varney, Sarah C. Garrett, Paul T. Wilder, David Knight, Thomas H. Charpentier, Udupi A. Ramagopal, Steven C. Almo, David J. Weber, Anne R. Bresnick

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Abstract

S100A4, also known as mts1, is a member of the S100 family of Ca 2+-binding proteins that is directly involved in tumor invasion and metastasis via interactions with specific protein targets, including nonmuscle myosin-IIA (MIIA). Human S100A4 binds two Ca2+ ions with the typical EF-hand exhibiting an affinity that is nearly 1 order of magnitude tighter than that of the pseudo-EF-hand. To examine how Ca2+ modifies the overall organization and structure of the protein, we determined the 1.7 Å crystal structure of the human Ca2+-S100A4. Ca2+ binding induces a large reorientation of helix 3 in the typical EF-hand. This reorganization exposes a hydrophobic cleft that is comprised of residues from the hinge region, helix 3, and helix 4, which afford specific target recognition and binding. The Ca2+-dependent conformational change is required for S100A4 to bind peptide sequences derived from the C-terminal portion of the MIIA rod with submicromolar affinity. In addition, the level of binding of Ca2+ to both EF-hands increases by 1 order of magnitude in the presence of MIIA. NMR spectroscopy studies demonstrate that following titration with a MIIA peptide, the largest chemical shift perturbations and exchange broadening effects occur for residues in the hydrophobic pocket of Ca2+-S100A4. Most of these residues are not exposed in apo-S100A4 and explain the Ca2+ dependence of formation of the S100A4-MIIA complex. These studies provide the foundation for understanding S100A4 target recognition and may support the development of reagents that interfere with S100A4 function.

Original languageEnglish (US)
Pages (from-to)5111-5126
Number of pages16
JournalBiochemistry
Volume47
Issue number18
DOIs
StatePublished - May 6 2008

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ASJC Scopus subject areas

  • Biochemistry

Cite this

Malashkevich, V. N., Varney, K. M., Garrett, S. C., Wilder, P. T., Knight, D., Charpentier, T. H., Ramagopal, U. A., Almo, S. C., Weber, D. J., & Bresnick, A. R. (2008). Structure of Ca2+-bound S100A4 and its interaction with peptides derived from nonmuscle myosin-IIA. Biochemistry, 47(18), 5111-5126. https://doi.org/10.1021/bi702537s