Research ArticleDRUG DISCOVERY

Identification of small-molecule inhibitors of calcineurin-NFATc signaling that mimic the PxIxIT motif of calcineurin binding partners

See allHide authors and affiliations

Sci. Signal.  23 Jun 2015:
Vol. 8, Issue 382, pp. ra63
DOI: 10.1126/scisignal.2005918

You are currently viewing the abstract.

View Full Text

Log in to view the full text

Log in through your institution

Log in through your institution

Abstract

Calcineurin (CN), a serine and threonine protein phosphatase that depends on Ca2+ and calmodulin for its activity, is the target of the immunosuppressant drugs cyclosporin A (CsA) and tacrolimus (FK506). CN dephosphorylates and activates members of the NFATc (nuclear factor of activated T cells) family of transcription factors in T cells by binding to their conserved PxIxIT motif. Upon dephosphorylation, NFATc proteins translocate to the nucleus, where they stimulate the expression of genes encoding cytokines and chemokines that are required for T cell proliferation and the immune response. We performed a pharmacophore-based virtual screening of ~5.5 million commercially available, “drug-like” compounds to identify nonpeptidic compounds that inhibited the CN-dependent activation of NFATc signaling and that could serve as potential drug candidates for immunosuppressive therapy. Of 32 compounds that mimicked the PxIxIT motif, 7 competed with NFATc for binding to CN in vitro without interfering with the phosphatase activity of CN. Furthermore, in activated human CD4+ T cells, four of the seven compounds inhibited the expression of NFATc-dependent genes, cytokine production, and cell proliferation, suggesting that these may have therapeutic potential as immunosuppressive agents.

View Full Text