A Novel Mitochondrial K(ATP) Channel Assay

Overview

Journal Circ Res

Specialty Cardiology & Vascular Diseases

Date 2010 Feb 27

PMID 20185796

Citations 29

Authors

Andrew P Wojtovich

David M Williams

Marcin K Karcz

Coeli M B Lopes

Daniel A Gray

Keith W Nehrke

Paul S Brookes

Affiliations

Soon will be listed here.

Abstract

Rationale: The mitochondrial ATP sensitive potassium channel (mK(ATP)) is implicated in cardioprotection by ischemic preconditioning (IPC), but the molecular identity of the channel remains controversial. The validity of current methods to assay mK(ATP) activity is disputed.

Objective: We sought to develop novel methods to assay mK(ATP) activity and its regulation.

Methods And Results: Using a thallium (Tl(+))-sensitive fluorophore, we developed a novel Tl(+) flux based assay for mK(ATP) activity, and used this assay probe several aspects of mK(ATP) function. The following key observations were made. (1) Time-dependent run down of mK(ATP) activity was reversed by phosphatidylinositol-4,5-bisphosphate (PIP(2)). (2) Dose responses of mK(ATP) to nucleotides revealed a UDP EC(50) of approximately 20 micromol/L and an ATP IC(50) of approximately 5 micromol/L. (3) The antidepressant fluoxetine (Prozac) inhibited mK(ATP) (IC(50)=2.4 micromol/L). Fluoxetine also blocked cardioprotection triggered by IPC, but did not block protection triggered by a mK(ATP)-independent stimulus. The related antidepressant zimelidine was without effect on either mK(ATP) or IPC.

Conclusions: The Tl(+) flux mK(ATP) assay was validated by correlation with a classical mK(ATP) channel osmotic swelling assay (R(2)=0.855). The pharmacological profile of mK(ATP) (response to ATP, UDP, PIP(2), and fluoxetine) is consistent with that of an inward rectifying K(+) channel (K(IR)) and is somewhat closer to that of the K(IR)6.2 than the K(IR)6.1 isoform. The effect of fluoxetine on mK(ATP)-dependent cardioprotection has implications for the growing use of antidepressants in patients who may benefit from preconditioning.

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References

Alekseev A, Hodgson D, Karger A, Park S, Zingman L, Terzic A . ATP-sensitive K+ channel channel/enzyme multimer: metabolic gating in the heart. J Mol Cell Cardiol. 2005; 38(6):895-905. PMC: 2736952. DOI: 10.1016/j.yjmcc.2005.02.022. View

Watt S, Kular G, Fleming I, Downes C, Lucocq J . Subcellular localization of phosphatidylinositol 4,5-bisphosphate using the pleckstrin homology domain of phospholipase C delta1. Biochem J. 2002; 363(Pt 3):657-66. PMC: 1222518. DOI: 10.1042/0264-6021:3630657. View

Nikitina E, Glazunov V . Involvement of K+-ATP-dependent channel in transport of monovalent thallium (Tl+) across the inner membrane of rat liver mitochondria. Dokl Biochem Biophys. 2004; 392:244-6. DOI: 10.1023/a:1026130527827. View

Shim Y, Kersten J . Preconditioning, anesthetics, and perioperative medication. Best Pract Res Clin Anaesthesiol. 2008; 22(1):151-65. DOI: 10.1016/j.bpa.2007.08.003. View

Auchampach J, Grover G, Gross G . Blockade of ischaemic preconditioning in dogs by the novel ATP dependent potassium channel antagonist sodium 5-hydroxydecanoate. Cardiovasc Res. 1992; 26(11):1054-62. DOI: 10.1093/cvr/26.11.1054. View

Kowaltowski A, Cosso R, Campos C, Fiskum G . Effect of Bcl-2 overexpression on mitochondrial structure and function. J Biol Chem. 2002; 277(45):42802-7. DOI: 10.1074/jbc.M207765200. View

Kuniyasu A, Kaneko K, Kawahara K, Nakayama H . Molecular assembly and subcellular distribution of ATP-sensitive potassium channel proteins in rat hearts. FEBS Lett. 2003; 552(2-3):259-63. DOI: 10.1016/s0014-5793(03)00936-0. View

Furutani K, Ohno Y, Inanobe A, Hibino H, Kurachi Y . Mutational and in silico analyses for antidepressant block of astroglial inward-rectifier Kir4.1 channel. Mol Pharmacol. 2009; 75(6):1287-95. DOI: 10.1124/mol.108.052936. View

Pagliarini D, Calvo S, Chang B, Sheth S, Vafai S, Ong S . A mitochondrial protein compendium elucidates complex I disease biology. Cell. 2008; 134(1):112-23. PMC: 2778844. DOI: 10.1016/j.cell.2008.06.016. View

10.

Hanley P, Gopalan K, Lareau R, Srivastava D, von Meltzer M, Daut J . Beta-oxidation of 5-hydroxydecanoate, a putative blocker of mitochondrial ATP-sensitive potassium channels. J Physiol. 2003; 547(Pt 2):387-93. PMC: 2342646. DOI: 10.1113/jphysiol.2002.037044. View

11.

Suzuki M, Sasaki N, Miki T, Sakamoto N, Ohmoto-Sekine Y, Tamagawa M . Role of sarcolemmal K(ATP) channels in cardioprotection against ischemia/reperfusion injury in mice. J Clin Invest. 2002; 109(4):509-16. PMC: 150878. DOI: 10.1172/JCI14270. View

12.

Mironova G, Negoda A, Marinov B, Paucek P, Costa A, Grigoriev S . Functional distinctions between the mitochondrial ATP-dependent K+ channel (mitoKATP) and its inward rectifier subunit (mitoKIR). J Biol Chem. 2004; 279(31):32562-8. DOI: 10.1074/jbc.M401115200. View

13.

Hille B . Potassium channels in myelinated nerve. Selective permeability to small cations. J Gen Physiol. 1973; 61(6):669-86. PMC: 2203488. DOI: 10.1085/jgp.61.6.669. View

14.

Bednarczyk P, Dolowy K, Szewczyk A . New properties of mitochondrial ATP-regulated potassium channels. J Bioenerg Biomembr. 2008; 40(4):325-35. DOI: 10.1007/s10863-008-9153-y. View

15.

Reimann F, Ashcroft F . Inwardly rectifying potassium channels. Curr Opin Cell Biol. 1999; 11(4):503-8. DOI: 10.1016/S0955-0674(99)80073-8. View

16.

Takano M, Xie L, Otani H, Horie M . Cytoplasmic terminus domains of Kir6.x confer different nucleotide-dependent gating on the ATP-sensitive K+ channel. J Physiol. 1998; 512 ( Pt 2):395-406. PMC: 2231215. DOI: 10.1111/j.1469-7793.1998.395be.x. View

17.

Kersten J, Toller W, Gross E, Pagel P, Warltier D . Diabetes abolishes ischemic preconditioning: role of glucose, insulin, and osmolality. Am J Physiol Heart Circ Physiol. 2000; 278(4):H1218-24. DOI: 10.1152/ajpheart.2000.278.4.H1218. View

18.

Suzuki M, Kotake K, FUJIKURA K, Inagaki N, Suzuki T, Gonoi T . Kir6.1: a possible subunit of ATP-sensitive K+ channels in mitochondria. Biochem Biophys Res Commun. 1998; 241(3):693-7. DOI: 10.1006/bbrc.1997.7891. View

19.

Xiong G, Jiang W, Clare R, Shaw L, Smith P, Mahaffey K . Prognosis of patients taking selective serotonin reuptake inhibitors before coronary artery bypass grafting. Am J Cardiol. 2006; 98(1):42-7. DOI: 10.1016/j.amjcard.2006.01.051. View

20.

Ardehali H, Chen Z, Ko Y, Mejia-Alvarez R, Marban E . Multiprotein complex containing succinate dehydrogenase confers mitochondrial ATP-sensitive K+ channel activity. Proc Natl Acad Sci U S A. 2004; 101(32):11880-5. PMC: 511068. DOI: 10.1073/pnas.0401703101. View