Interaction of Selective Amino Acid Residues of K Ca Channels with Carbon Monoxide

Abstract

The activation of big-conductance K_Ca channels in vascular smooth muscle cells by carbon monoxide (CO) has been demonstrated previously. One specific target of CO on K_Ca channel proteins is the histidine residue. The roles of other amino acid residues on the functionality of K_Ca channels, as well as their reactions to CO, have been unclear. In the present study, the cell-free single channel recording technique was used to investigate the chemical modification of K_Ca channels by CO and other chemical agents. The modification of negatively charged carboxyl groups and the ε-amino group of lysine did not affect the open probability, but decreased single-channel conductance of K_Ca channels. When sulfhydryl groups of cysteine were modified with N-ethylmaleimide, the open probability of K_Ca channels was decreased, but single-channel conductance was not affected. None of the above chemical modifications affected the CO-induced increase in the open probability of K_Ca channels. However, N-ethylmaleimide treatment reduced the stimulatory effect of nitric oxide (NO) on K_Ca channels. Finally, pretreatment of smooth muscle cells with NO abolished the effects of subsequently applied CO on K_Ca channel proteins. Our study demonstrates that CO and NO acted on different amino acid residues of K_Ca channel proteins. The interaction of CO and NO determines the functional status of K_Ca channels in vascular smooth muscle cells

Get full access to this article

View all access options for this article.

References

Wang R. Resurgence of carbon monoxide: An endogenous gaseous vasorelaxing factor. Can J Physiol Pharmacol 76 : 1–15, 1998.

Zhao W, Wang R. Carbon monoxide-induced vasorelaxation and the underlying mechanisms. In: Wang R, Ed. CO and Cardiovascular Functions. Baca Raton: CRC Press, pp23–44, 2001.

Wang R, Wu L. The chemical modification of K_Ca channels by carbon monoxide in vascular smooth muscle cells. J Biol Chem 272 : 8222–8226, 1997.

Wang R, Wu L, Wang ZZ. The direct effect of carbon monoxide on K_Ca channels in vascular smooth muscle cells. Pflügers Arch 434 : 285–291, 1997.

Cao K, Wang R. Carbon monoxide, Vascular contractility, and K⁺ channels. In: Wang R, Ed. CO and Cardiovascular Functions. Baca Raton: CRC Press, pp83–109, 2001.

Kaide JI, Zhang F, Wei Y, Jiang H, Yu C, Wang WH, Balazy M, Abraham NG, Nasjletti A. Carbon monoxide of vascular origin attenuates the sensitivity of renal arterial vessels to vasoconstrictors. J Clin Invest 107 : 1163–1171, 2001.

Bolotina VM, Najibi S, Palacino JJ, Pagano PJ, Cohen RA. Nitric oxide directly activates calcium-dependent potassium channels in vascular smooth muscle. Nature 368 : 850–853, 1994.

Frace AM, Eaton DC. Chemical modification of Ca²⁺-activated potassium channels of GH3 anterior pituitary cells. Am J Physiol 263 : C1081–C1087, 1992.

MacKinnon R, Miller C. Functional modification of a Ca²⁺-activated K⁺ channel by trimethyloxonium. Biochemistry 28 : 8087–8092, 1989.

10.

Wang R. Two’s company, three’s a crowd – Can H₂S be the third endogenous gaseous transmitter? FASEB J 16 : 1792–1798, 2002.

11.

Wang R, Karpinski E, Pang PKT. Two types of calcium channels in isolated smooth muscle cells from rat tail artery. Am J Physiol 256 : H1361–H1368, 1989.

12.

Wang R, Wang ZZ, Wu L, Hanna ST, Peterson-Wakeman R. Reduced vasorelaxant effect of carbon monoxide in diabetes and the underlying mechanisms. Diabetes 50 : 166–174, 2001.

13.

Wang R, Wang ZZ, Wu L. Carbon monoxide-induced vasorelaxation and the underlying mechanisms. Br J Pharmacol 121 : 927–934, 1997.

14.

Lee K, Ozanne SE, Hales CN, Ashford MLJ. Effects of chemical modification of amino and sulfhydryl groups on KATP channel function and sulfonylurea binding in CRI-G1 insulin-secreting cells. J Membr Biol 139 : 167–181, 1994.

15.

Spires S, Begenisich T. Modification of potassium channel kinetics by amino group reagents. J Gen Physiol 99 : 109–129, 1992.

16.

Pappone PA, Barchfeld GL. Modifications of single acetylcholine-activated channels in BC3H-1 cells. Effects of trimethyloxonium and pH. J Gen Physiol 96 : 1–22, 1990.

17.

Worley JF, French RJ, Krueger BK. Trimethyloxonium modification of single batrachotoxin-activated sodium channels in planar bilayers. Changes in unit conductance and in block by saxitoxin and calcium. J Gen Physiol 87 : 327–349, 1986.

18.

Sigworth FJ, Spalding BC. Chemical modification reduces the conductance of sodium channels in nerve. Nature 283 : 293–295, 1980.

19.

Munujos P, Knaus H, Kaczorowski GJ, Garcia ML. Cross-linking of charybdotoxin to high-conductance calcium-activated potassium channels: Identification of the covalently modified toxin residue. Biochemistry 34 : 10771–10776, 1995.

20.

Cescatti L, Pederzolli C, Menestrina G. Modification of lysine residues of Staphylococcus aureus alpha-toxin: Effects on its channel-forming properties. J Membr Biol 119 : 53–64, 1991.

21.

Kenyon GL, Bruice TW. Novel sulfhydryl reagents. In: Colowick SP, Kaplan NO. Ed. Methods in Enzymology, New York: Academic Press, Vol 47:pp407–430, 1997.

22.

Bouzat CB, Barrantes FJ, Sigworth FJ. Changes in channel properties of acetylcholine receptors during the time course of thiol chemical modifications. Pflugers Arch 418 : 51–61, 1991.

23.

Christensen BN, Hida E. Protonation of histidine groups inhibits gating of the quisqualate/kainate channel protein in isolated catfish cone horizontal cells. Neuron 5 : 471–478, 1990.