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Ionomycin, Calcium Salt
Activators & Inhibitors

Ionomycin, Calcium Salt #9995


Confocal immunofluorescent analysis of MCF7 cells, untreated (left) or treated with Ionomycin (1 μM, 1 hr; right), using NFAT1 (D43B1) XP® Rabbit mAb #5861 (green). Actin filaments were labeled with DyLight™ 554 Phalloidin #13054 (red). Blue pseudocolor = DRAQ5® #4084 (fluorescent DNA dye).

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Ionomycin, calcium salt is supplied as 2.5 mg powder. Store at or below -20ºC. Before use, dissolve powder in 1.1 ml DMSO to make a 3 mM ionomycin stock solution. For working concentrations of 1 μM-3 μM, dilute DMSO stock 1:3000 to 1:1000. Treat cells with the desired concentration for intended time.


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:

747.1 g/mol



Molecular Formula:

C41H70O9 • Ca2+

Ionomycin is a potent and selective calcium ionophore agent (1,2). The molecule acts as a motile Ca2+ carrier and enhances Ca2+ influx by direct stimulation of store-regulated cation entry across biological membranes (3). At the micromolar level, ionomycin can activate Ca2+/Calmodulin dependent kinase and phosphatase to stimulate gene expression (4). In human T cells, ionomycin induces hydrolysis of phosphoinositides and activates PKC to mediate T cell activation (5). Ionomycin treatment of human B cells induces the activation of calcium-dependent endonuclease and results in apoptosis (6). Ionomycin treatment of bovine aortic endothelial cells (BAECs) induces rapid dephosphorylation of eNOS at Thr495 and mediates eNOS activation (7).

  1. Liu, C. and Hermann, T.E. (1978) J Biol Chem 253, 5892-4.
  2. Kauffman, R.F. et al. (1980) J Biol Chem 255, 2735-9.
  3. Morgan, A.J. and Jacob, R. (1994) Biochem J 300 ( Pt 3), 665-72.
  4. Lobo, F.M. et al. (1999) J Immunol 162, 2057-63.
  5. Chatila, T. et al. (1989) J Immunol 143, 1283-9.
  6. Aagaard-Tillery, K.M. and Jelinek, D.F. (1995) J Immunol 155, 3297-307.
  7. Lin, M.I. et al. (2003) J Biol Chem 278, 44719-26.
For Research Use Only. Not For Use In Diagnostic Procedures.

Cell Signaling Technology is a trademark of Cell Signaling Technology, Inc.

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To Purchase # 9995S

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Product # Size Price
2.5 mg $ 221.0