A biosensor of S100A4 metastasis factor activation: Inhibitor screening and cellular activation dynamics

Sarah C. Garrett, Louis Hodgson, Andrew Rybin, Alexei Toutchkine, Klaus M. Hahn, David S. Lawrence, Anne R. Bresnick

Research output: Contribution to journalArticle

49 Scopus citations


S100A4, a member of the S100 family of Ca2+-binding proteins, displays elevated expression in malignant human tumors compared with benign tumors, and increased expression correlates strongly with poor patient survival. S100A4 has a direct role in metastatic progression, likely due to the modulation of actomyosin cytoskeletal dynamics, which results in increased cellular motility. We developed a fluorescent biosensor (Mero-S100A4) that reports on the Ca2+-bound, activated form of S100A4. Direct attachment of a novel solvatochromatic reporter dye to S100A4 results in a sensor that, upon activation, undergoes a 3-fold enhancement in fluorescence, thus providing a sensitive assay for use in vitro and in vivo. In cells, localized activation of S100A4 at the cell periphery is observed during random migration and following stimulation with lysophosphatidic acid, a known activator of cell motility and proliferation. Additionally, a screen against a library of FDA-approved drugs with the biosensor identified an array of phenothiazines as inhibitors of myosin-II associated S100A4 function. These data demonstrate the utility of the new biosensor both for drug discovery and for probing the cellular dynamics controlled by the S100A4 metastasis factor.

Original languageEnglish (US)
Pages (from-to)986-996
Number of pages11
Issue number3
StatePublished - Jan 22 2008


ASJC Scopus subject areas

  • Biochemistry

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