TY - JOUR
T1 - The cardiac inward rectifier K+ channel subunit, CIR, does not comprise the ATP-sensitive K+ channel, IKATP
AU - Krapivinsky, Grigory
AU - Krapivinsky, Luba
AU - Velimirovic, Bratislav
AU - Wickman, Kevin
AU - Navarro, Betsy
AU - Clapham, David E.
PY - 1995/12/1
Y1 - 1995/12/1
N2 - Cardiac IKACh is comprised of two inwardly rectifying K+ channel subunits, CIR and GIRK1 (Krapivinsky, G., Gordon, E. G., Wickman, K., Velimirovic, B., Krapivinsky, L., and Clapham, D. E. (1995) Nature 374, 135-141). A cardiac protein virtually identical to CIR, termed rcKATP-1 (Ashford, M. L. J., Bond, C. T., Blair, T. A., and Adelman, J. P. (1994) Nature 370, 456-459), was reported to form an ATP-sensitive inwardly rectifying K+ channel, IKATP. We attempted to determine whether CIR alone or together with an unknown protein(s) participated in the formation of cardiac IKATP. Expression of CIR in insect, oocyte, and mammalian cell systems did not increase the appearance of ATP-sensitive currents, but rather gave rise to unique strongly inwardly rectifying, G protein-regulated K+ currents. CIR protein is found exclusively in atria, in contrast to the predominance of IKATP functional activity in ventricle. Also, CIR was completely depleted from heart membrane after immunodepletion of GIRK1. We conclude that CIR/rcKATP-1 is not a subunit of cardiac IKATP and that GIRK1 is the only channel protein coassociating with CIR in heart.
AB - Cardiac IKACh is comprised of two inwardly rectifying K+ channel subunits, CIR and GIRK1 (Krapivinsky, G., Gordon, E. G., Wickman, K., Velimirovic, B., Krapivinsky, L., and Clapham, D. E. (1995) Nature 374, 135-141). A cardiac protein virtually identical to CIR, termed rcKATP-1 (Ashford, M. L. J., Bond, C. T., Blair, T. A., and Adelman, J. P. (1994) Nature 370, 456-459), was reported to form an ATP-sensitive inwardly rectifying K+ channel, IKATP. We attempted to determine whether CIR alone or together with an unknown protein(s) participated in the formation of cardiac IKATP. Expression of CIR in insect, oocyte, and mammalian cell systems did not increase the appearance of ATP-sensitive currents, but rather gave rise to unique strongly inwardly rectifying, G protein-regulated K+ currents. CIR protein is found exclusively in atria, in contrast to the predominance of IKATP functional activity in ventricle. Also, CIR was completely depleted from heart membrane after immunodepletion of GIRK1. We conclude that CIR/rcKATP-1 is not a subunit of cardiac IKATP and that GIRK1 is the only channel protein coassociating with CIR in heart.
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U2 - 10.1074/jbc.270.48.28777
DO - 10.1074/jbc.270.48.28777
M3 - Article
C2 - 7499400
AN - SCOPUS:0028868771
SN - 0021-9258
VL - 270
SP - 28777
EP - 28779
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 48
ER -