Abstract
Involvement of voltage-gated (Kv) potassium channels in IGF-1-induced proliferation of HEK293 cells was studied by patch-clamp, RT-PCR and FACS analysis. IGF-1 up-regulated outwardly rectifying whole-cell K+ current starting after 1 h of incubation and reaching a maximum after 4-6 h. The IGF-1-stimulated current was voltage-gated with an activation threshold of -30 mV to -40 mV, a half-maximal activation at +5.3±1.8 mV, and time constants for activation and inactivation of 4.5±0.4 ms and 43.5±5.6 ms (n=10), respectively. The current was inhibited by TEA, margatoxin, agitoxin-2 and stichodactyla toxin. PCR amplification of different Kv subunits from HEK293 cDNA demonstrated the expression of Kv1.1, Kv1.2, Kv1.3, Kv1.4, Kv3.1 and Kv3.4 mRNA. Quantitative RT-PCR showed up-regulation of Kv1.1, 1.2 and 1.3 mRNA by IGF-1. The effect of IGF-1 on K+ current was blocked by inhibitors of phosphatidylinositol 3-kinase (PI3-kinase), wortmannin and LY294002, and mimicked by overexpression of human 3-phosphoinositide-dependent protein kinase-1 (hPDK1) or serum- and glucocorticoid-dependent kinase-1 (hSGK1), both sequential downstream targets of PI3-kinase. IGF-1-induced proliferation of HEK293 cells was inhibited by both K+ channel blockers and inhibitors of PI3-kinase. In conclusion, IGF-1 through PI3-kinase, PDK1 and SGK1 up-regulates Kv channels, an effect required for the proliferative action of the growth factor.
| Original language | English |
|---|---|
| Pages (from-to) | 625-634 |
| Number of pages | 10 |
| Journal | Pflugers Archiv European Journal of Physiology |
| Volume | 443 |
| Issue number | 4 |
| DOIs | |
| Publication status | Published - 11 Mar 2002 |
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Keywords
- Cell proliferation
- Growth factor
- Kv1.3
- Margatoxin
- Wortmannin
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IGF-1 up-regulates K+ channels via PI3-kinase, PDK1 and SGK1. / Gamper, N.; Fillon, S.; Huber, S.; Feng, Y.; Kobayashi, T.; Cohen, P.; Lang, F.
In: Pflugers Archiv European Journal of Physiology, Vol. 443, No. 4, 11.03.2002, p. 625-634.Research output: Contribution to journal › Article
TY - JOUR
T1 - IGF-1 up-regulates K+ channels via PI3-kinase, PDK1 and SGK1
AU - Gamper, N.
AU - Fillon, S.
AU - Huber, S.
AU - Feng, Y.
AU - Kobayashi, T.
AU - Cohen, P.
AU - Lang, F.
PY - 2002/3/11
Y1 - 2002/3/11
N2 - Involvement of voltage-gated (Kv) potassium channels in IGF-1-induced proliferation of HEK293 cells was studied by patch-clamp, RT-PCR and FACS analysis. IGF-1 up-regulated outwardly rectifying whole-cell K+ current starting after 1 h of incubation and reaching a maximum after 4-6 h. The IGF-1-stimulated current was voltage-gated with an activation threshold of -30 mV to -40 mV, a half-maximal activation at +5.3±1.8 mV, and time constants for activation and inactivation of 4.5±0.4 ms and 43.5±5.6 ms (n=10), respectively. The current was inhibited by TEA, margatoxin, agitoxin-2 and stichodactyla toxin. PCR amplification of different Kv subunits from HEK293 cDNA demonstrated the expression of Kv1.1, Kv1.2, Kv1.3, Kv1.4, Kv3.1 and Kv3.4 mRNA. Quantitative RT-PCR showed up-regulation of Kv1.1, 1.2 and 1.3 mRNA by IGF-1. The effect of IGF-1 on K+ current was blocked by inhibitors of phosphatidylinositol 3-kinase (PI3-kinase), wortmannin and LY294002, and mimicked by overexpression of human 3-phosphoinositide-dependent protein kinase-1 (hPDK1) or serum- and glucocorticoid-dependent kinase-1 (hSGK1), both sequential downstream targets of PI3-kinase. IGF-1-induced proliferation of HEK293 cells was inhibited by both K+ channel blockers and inhibitors of PI3-kinase. In conclusion, IGF-1 through PI3-kinase, PDK1 and SGK1 up-regulates Kv channels, an effect required for the proliferative action of the growth factor.
AB - Involvement of voltage-gated (Kv) potassium channels in IGF-1-induced proliferation of HEK293 cells was studied by patch-clamp, RT-PCR and FACS analysis. IGF-1 up-regulated outwardly rectifying whole-cell K+ current starting after 1 h of incubation and reaching a maximum after 4-6 h. The IGF-1-stimulated current was voltage-gated with an activation threshold of -30 mV to -40 mV, a half-maximal activation at +5.3±1.8 mV, and time constants for activation and inactivation of 4.5±0.4 ms and 43.5±5.6 ms (n=10), respectively. The current was inhibited by TEA, margatoxin, agitoxin-2 and stichodactyla toxin. PCR amplification of different Kv subunits from HEK293 cDNA demonstrated the expression of Kv1.1, Kv1.2, Kv1.3, Kv1.4, Kv3.1 and Kv3.4 mRNA. Quantitative RT-PCR showed up-regulation of Kv1.1, 1.2 and 1.3 mRNA by IGF-1. The effect of IGF-1 on K+ current was blocked by inhibitors of phosphatidylinositol 3-kinase (PI3-kinase), wortmannin and LY294002, and mimicked by overexpression of human 3-phosphoinositide-dependent protein kinase-1 (hPDK1) or serum- and glucocorticoid-dependent kinase-1 (hSGK1), both sequential downstream targets of PI3-kinase. IGF-1-induced proliferation of HEK293 cells was inhibited by both K+ channel blockers and inhibitors of PI3-kinase. In conclusion, IGF-1 through PI3-kinase, PDK1 and SGK1 up-regulates Kv channels, an effect required for the proliferative action of the growth factor.
KW - Cell proliferation
KW - Growth factor
KW - Kv1.3
KW - Margatoxin
KW - Wortmannin
UR - http://www.scopus.com/inward/record.url?scp=0036191636&partnerID=8YFLogxK
U2 - 10.1007/s00424-001-0741-5
DO - 10.1007/s00424-001-0741-5
M3 - Article
VL - 443
SP - 625
EP - 634
JO - Pflugers Archiv-European Journal of Physiology
JF - Pflugers Archiv-European Journal of Physiology
SN - 0031-6768
IS - 4
ER -