Description
Ionomycin (56092-81-0) is a highly selective nonfluorescent calcium (Ca2+) ionophore.1 Induces a rapid rise in cytosolic Ca2+ in human neutrophils which is due to both release from cytosolic Ca2+ stores as well as Ca2+ influx.2 It activates (2 μM) and primes (20-200 nM) neutrophil NADPH oxidase2. Down regulates beta-catenin/Tcf signaling in a colon cancer cell line via suppressing the binding of Tcf to its specific DNA-binding site.3 In rat hepatoma cells, sub-lethal ionomycin activates the stress response by activating SAPK/JNK and HSF/HSE interaction leading to upregulation of HSP70 biosynthesis.4
Chemical Properties
White powder
Uses
Ionomycin is more effective than A23187 as a Ca++ionophore.
Ionomycin is used in research on Ca++ transport across biological membranes;
Ionomycin induces apoptotic degeneration of embryonic cortical neurons
Uses
Ionomycin was isolated from Streptomyces conglobatus as a potent Gram positive antibiotic . During isolation, it was recognised that ionomycin exhibits a very high affinity and selectivity for calcium ions, suggesting the metabolite acts as a calcium ionophore. More recently, ionomycin has been used in cell biology as a universal calcium ionophore to explore the role of calcium regulation in the cell.
Definition
ChEBI: A very long-chain fatty acid that is docosa-10,16-dienoic acid which is substituted by methyl groups at positions 4, 6, 8, 12, 14, 18 and 20, by hydroxy groups at positions 11, 19 and 21, and by a (2',5-dimethyloctahydro-2,2'-bifuran-5-yl)ethanol group at
osition 21. An ionophore produced by Streptomyces conglobatus, it is used in research to raise the intracellular level of Ca2+ and as a research tool to understand Ca2+ transport across biological memb
anes.
General Description
Highly specific for divalent cations (Ca2+ > Mg2+ >> Sr2+ = Ba2+). More effective than antibiotic A23187 as a mobile ion carrier for Ca2+. Complexes with Ca2+ between pH 7 and 9.5, causing significant absorption in the UV range; however, in contrast to A23187 (Cat. No. 100105), it is not fluorescent. Useful for studies of Ca2+ transport across biological membranes and measurement of cytoplasmic free Ca2+. Induces apoptotic neuronal degeneration in embryonic cortical neurons. Also induces cell cycle arrest in the G1 interval of mature Burkitt lymphoma cell lines.
Biological Activity
Calcium ionophore; more specific than A23187 (5-(Methylamino)-2-[[2R,3R,6S,8S,9R,11R)-3,9,11-trimethyl-8-[(1S)-1-methyl-2-oxo-2-(1H-pyrrol-2-yl)-ethyl]-1,7-dioxaspiro[5.5]undec-2-yl]methyl]-4-benzoxazolecarboxylic acid ).
Biochem/physiol Actions
Cell permeable: yes
in vitro
calcium ion can be extracted by ionomycin fom the queous phase into the organic phase. ionomycin also acts as a mobile ion carrier, which transports the cation across a solvent barrier [1].
in vivo
efficiency of ionomycin on oocyte activation and subsequent development was evaluated, which identified ionomycin as an efficient activator at the concentation of 10 μmol/l. with a second exposure to 5 μmol/l ionomycin on blastocyst development, an improved effect was found. no adverse effects of ionomycin on mouse embryo development were identified [2].
References
1) Kaufmann et al., (1980), Cation transport and specificity of ionomycin. Comparison with ionophore A23187 in rat liver mitochondria; J. Biol. Chem. 255 2735
2) Elzi et al., (2001), Ionomycin causes activation of p38 and p42/44 mitogen-activated protein kinases in human neutrophils; Am. J. Physiol. Cell Physiol. 281 C350
3) Park et al., (2005), Ionomycin downregulates beta-catenin/tcf signaling in colon cancer cell line; Carcinogenesis, 26 1929
4) Sreedhar and Srinivas (2002), Activation of stress response by ionomycin in rat hepatoma cells; J. Cell Biochem., 86 154