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Activators & Inhibitors

FK-506 #9974


Dose response inhibition of IL-2 secretion by FK-506 in Jurkat cells treated overnight with TPA (40 nM) and A23187 (2 μM).

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FK-506 is supplied as a 10 mg powder. Store at -20ºC. FK-506 is soluble in ethanol (also DMSO and methanol) and stock solutions should be stored at -20ºC. Working concentrations and length of treatment can vary depending on the desired effect, but it is typically used between 1 and 10 nM.


Store lyophilized or in solution at -20ºC, desiccated. Protect from light. In lyophilized form, the chemical is stable for 24 months. Once in solution, use within 3 months to prevent loss of potency. Aliquot to avoid multiple freeze/thaw cycles.

Molecular Weight:

804.03 g/mol



Molecular Formula:


The calcium dependent protein phosphatase calcineurin is responsible for the de-phosphorylation of the transcriptional regulator nuclear factor of activated T cells (NFAT) and is essential for NFAT’s nuclear translocation and activation (1,2). Calcineurin is a target of two common immunosuppressants, cyclosporin A (CsA) (3) and FK-506 (also know as tacrolimus and fugimycin) (4), both of which can inhibit antigen and mitogen triggered T cell activation. These drugs interact with the immunophilins cyclophilin and FKBP-12, respectively, and the immunophilin-drug complex binds to calcineurin to inhibit substrate binding (5). FK-506 can be up to 100-fold more potent than CsA in various models (6-8).

  1. Schulz, R.A. and Yutzey, K.E. (2004) Dev Biol 266, 1-16.
  2. Rusnak, F. and Mertz, P. (2000) Physiol Rev 80, 1483-521.
  3. Borel, J.F. et al. (1976) Agents Actions 6, 468-75.
  4. Kino, T. et al. (1987) J Antibiot (Tokyo) 40, 1249-55.
  5. Liu, J. et al. (1991) Cell 66, 807-15.
  6. Henderson, D.J. et al. (1991) Immunology 73, 316-21.
  7. Tocci, M.J. et al. (1989) J Immunol 143, 718-26.
  8. Yoshimura, N. et al. (1989) Transplantation 47, 351-6.
For Research Use Only. Not For Use In Diagnostic Procedures.

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