TY - JOUR
T1 - Subcellular localization of the delayed rectifier K(+) channels KCNQ1 and ERG1 in the rat heart.
AU - Rasmussen, Hanne Borger
AU - Møller, Morten
AU - Knaus, Hans-Günther
AU - Jensen, Bo Skaaning
AU - Olesen, Søren-Peter
AU - Jørgensen, Nanna Koschmieder
N1 - Keywords: Action Potentials; Animals; Antibodies, Blocking; Blotting, Western; Ether-A-Go-Go Potassium Channels; Immunohistochemistry; KCNQ Potassium Channels; KCNQ1 Potassium Channel; Microscopy, Confocal; Microscopy, Immunoelectron; Myocardium; Myocytes, Cardiac; Potassium Channel Blockers; Potassium Channels; Potassium Channels, Voltage-Gated; Rats; Sarcolemma; Subcellular Fractions
PY - 2003
Y1 - 2003
N2 - In the heart, several K(+) channels are responsible for the repolarization of the cardiac action potential, including transient outward and delayed rectifier K(+) currents. In the present study, the cellular and subcellular localization of the two delayed rectifier K(+) channels, KCNQ1 and ether-a-go-go-related gene-1 (ERG1), was investigated in the adult rat heart. Confocal immunofluorescence microscopy of atrial and ventricular cells revealed that whereas KCNQ1 labeling was detected in both the peripheral sarcolemma and a structure transversing the myocytes, ERG1 immunoreactivity was confined to the latter. Immunoelectron microscopy of atrial and ventricular myocytes showed that the ERG1 channel was primarily expressed in the transverse tubular system and its entrance, whereas KCNQ1 was detected in both the peripheral sarcolemma and in the T tubules. Thus, whereas ERG1 displays a very restricted subcellular localization pattern, KCNQ1 is more widely distributed within the cardiac cells. The localization of these K(+) channels to the transverse tubular system close to the Ca(2+) channels renders them with maximal repolarizing effect.
AB - In the heart, several K(+) channels are responsible for the repolarization of the cardiac action potential, including transient outward and delayed rectifier K(+) currents. In the present study, the cellular and subcellular localization of the two delayed rectifier K(+) channels, KCNQ1 and ether-a-go-go-related gene-1 (ERG1), was investigated in the adult rat heart. Confocal immunofluorescence microscopy of atrial and ventricular cells revealed that whereas KCNQ1 labeling was detected in both the peripheral sarcolemma and a structure transversing the myocytes, ERG1 immunoreactivity was confined to the latter. Immunoelectron microscopy of atrial and ventricular myocytes showed that the ERG1 channel was primarily expressed in the transverse tubular system and its entrance, whereas KCNQ1 was detected in both the peripheral sarcolemma and in the T tubules. Thus, whereas ERG1 displays a very restricted subcellular localization pattern, KCNQ1 is more widely distributed within the cardiac cells. The localization of these K(+) channels to the transverse tubular system close to the Ca(2+) channels renders them with maximal repolarizing effect.
U2 - 10.1152/ajpheart.00344.2003
DO - 10.1152/ajpheart.00344.2003
M3 - Journal article
C2 - 14670813
SN - 0363-6135
VL - 286
SP - H1300-9
JO - American Journal of Physiology - Heart and Circulatory Physiology
JF - American Journal of Physiology - Heart and Circulatory Physiology
IS - 4
ER -