Abstract
Voltage-gated K+ channels play an essential role in the production of action potential activity by excitable cells. Recent studies have suggested that expression of K+ channel genes may be regulated by stimuli that affect electrical activity. Elevating the concentration of extracellular KCl causes membrane depolarization and, thus, is widely used for studying electrical activity-dependent changes in neurons, muscle, and endocrine cells. Here we show that elevated KCl decreases Kv1.5 K+ channel mRNA expression in clonal pituitary cells without affecting Kv1.4 and Kv2.1 mRNA levels. K+ channel blockers, which cause depolarization, also produce down-regulation of Kv1.5 mRNA, while NaCl addition had no effect. Thus, the effect of KCl is mediated by K+-induced membrane depolarization. Unlike many known effects of K+, down-regulation of Kv1.5 mRNA does not require Ca2+ or Na+ influx, or Na+-H+ exchange. Furthermore, the decrease in Kv1.5 mRNA expression is due to inhibition of channel gene transcription and persists after inhibition of protein synthesis, excluding a role for induction of intermediary regulatory proteins. Finally, immunoblots with antibody specific for the Kv1.5 polypeptide show that depolarization for 8 h reduces the expression of Kv1.5 channel protein. The decrease in K+ channel protein expression caused by depolarization-induced Ca2+-independent inhibition of Kv1.5 gene transcription may produce a long-term enhancement of pituitary cell excitability and secretory activity.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 6036-6041 |
| Number of pages | 6 |
| Journal | Journal of Biological Chemistry |
| Volume | 270 |
| Issue number | 11 |
| DOIs | |
| State | Published - Mar 17 1995 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Biochemistry
Cite this
Membrane depolarization inhibits Kv1.5 voltage-gated K+ channel gene transcription and protein expression in pituitary cells. / Levitan, Edwin S.; Gealy, Robert; Trimmer, James; Takimoto, Koichi.
In: Journal of Biological Chemistry, Vol. 270, No. 11, 17.03.1995, p. 6036-6041.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Membrane depolarization inhibits Kv1.5 voltage-gated K+ channel gene transcription and protein expression in pituitary cells
AU - Levitan, Edwin S.
AU - Gealy, Robert
AU - Trimmer, James
AU - Takimoto, Koichi
PY - 1995/3/17
Y1 - 1995/3/17
N2 - Voltage-gated K+ channels play an essential role in the production of action potential activity by excitable cells. Recent studies have suggested that expression of K+ channel genes may be regulated by stimuli that affect electrical activity. Elevating the concentration of extracellular KCl causes membrane depolarization and, thus, is widely used for studying electrical activity-dependent changes in neurons, muscle, and endocrine cells. Here we show that elevated KCl decreases Kv1.5 K+ channel mRNA expression in clonal pituitary cells without affecting Kv1.4 and Kv2.1 mRNA levels. K+ channel blockers, which cause depolarization, also produce down-regulation of Kv1.5 mRNA, while NaCl addition had no effect. Thus, the effect of KCl is mediated by K+-induced membrane depolarization. Unlike many known effects of K+, down-regulation of Kv1.5 mRNA does not require Ca2+ or Na+ influx, or Na+-H+ exchange. Furthermore, the decrease in Kv1.5 mRNA expression is due to inhibition of channel gene transcription and persists after inhibition of protein synthesis, excluding a role for induction of intermediary regulatory proteins. Finally, immunoblots with antibody specific for the Kv1.5 polypeptide show that depolarization for 8 h reduces the expression of Kv1.5 channel protein. The decrease in K+ channel protein expression caused by depolarization-induced Ca2+-independent inhibition of Kv1.5 gene transcription may produce a long-term enhancement of pituitary cell excitability and secretory activity.
AB - Voltage-gated K+ channels play an essential role in the production of action potential activity by excitable cells. Recent studies have suggested that expression of K+ channel genes may be regulated by stimuli that affect electrical activity. Elevating the concentration of extracellular KCl causes membrane depolarization and, thus, is widely used for studying electrical activity-dependent changes in neurons, muscle, and endocrine cells. Here we show that elevated KCl decreases Kv1.5 K+ channel mRNA expression in clonal pituitary cells without affecting Kv1.4 and Kv2.1 mRNA levels. K+ channel blockers, which cause depolarization, also produce down-regulation of Kv1.5 mRNA, while NaCl addition had no effect. Thus, the effect of KCl is mediated by K+-induced membrane depolarization. Unlike many known effects of K+, down-regulation of Kv1.5 mRNA does not require Ca2+ or Na+ influx, or Na+-H+ exchange. Furthermore, the decrease in Kv1.5 mRNA expression is due to inhibition of channel gene transcription and persists after inhibition of protein synthesis, excluding a role for induction of intermediary regulatory proteins. Finally, immunoblots with antibody specific for the Kv1.5 polypeptide show that depolarization for 8 h reduces the expression of Kv1.5 channel protein. The decrease in K+ channel protein expression caused by depolarization-induced Ca2+-independent inhibition of Kv1.5 gene transcription may produce a long-term enhancement of pituitary cell excitability and secretory activity.
UR - http://www.scopus.com/inward/record.url?scp=0028970263&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0028970263&partnerID=8YFLogxK
U2 - 10.1074/jbc.270.11.6036
DO - 10.1074/jbc.270.11.6036
M3 - Article
C2 - 7890735
AN - SCOPUS:0028970263
VL - 270
SP - 6036
EP - 6041
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
SN - 0021-9258
IS - 11
ER -