TY - JOUR
T1 - Regulation of a Ca2+-Activated K+ Channel by Calcium-Sensing Receptor Involves p38 MAP Kinase
AU - Ye, Chian Ping
AU - Yano, Shozo
AU - Tfelt-Hansen, Jacob
AU - MacLeod, R. John
AU - Ren, Xianghui
AU - Terwilliger, Ernest
AU - Brown, Edward M.
AU - Chattopadhyay, Naibedya
PY - 2004/2/15
Y1 - 2004/2/15
N2 - By using pharmacological and molecular approaches, we previously showed that the G-protein-coupled, extracellular calcium (Ca2+
o)-sensing receptor (CaR) regulates a large-conductance (∼140 pS), Ca2+-activated K+ channel [IK(Ca); CAKC] in U87 astrocytoma cells. Here we show that elevated Ca2+
o stimulates extracellular-signal-regulated kinase (ERK1/2) and p38 MAP kinase (MAPK). The effect of high Ca2+
o on p38 MAPK but not ERK1/2 is CaR mediated, insofar as transduction with a dominant-negative CaR (R185Q) using recombinant adeno-associated virus (rAAV) attenuated the activation of p38 MAPK but not of ERK1/2. p38 MAPK activation by the CaR is likely to be protein kinase C (PKC) independent, in that the pan-PKC inhibitor GF109203X failed to abolish the high-Ca2+
o-induced phosphorylation of p38 MAPK. Consistently with our data on the activation of this kinase, we observed that inhibiting p38 MAPK blocked the activation of the CAKC induced by the specific pharmacological CaR activator NPS R-467. In contrast, inhibiting MEK1 only transiently inhibited the activation of this K+ channel by NPS R-467, despite the continued presence of the antagonist. Similarly to the lack of any effect of the PKC inhibitor on the activation of ERK1/2 and p38 MAPK, inhibiting PKC had no effect on NPS R-467-induced activation of this channel. Therefore, our data show that the CaR, acting via p38 MAPK, regulates a large-conductance CAKC in U87 cells, a process that is PKC independent. Large-conductance CAKCs play an important role in the regulation of cellular volume, so our results have important implications for glioma cell volume regulation.
AB - By using pharmacological and molecular approaches, we previously showed that the G-protein-coupled, extracellular calcium (Ca2+
o)-sensing receptor (CaR) regulates a large-conductance (∼140 pS), Ca2+-activated K+ channel [IK(Ca); CAKC] in U87 astrocytoma cells. Here we show that elevated Ca2+
o stimulates extracellular-signal-regulated kinase (ERK1/2) and p38 MAP kinase (MAPK). The effect of high Ca2+
o on p38 MAPK but not ERK1/2 is CaR mediated, insofar as transduction with a dominant-negative CaR (R185Q) using recombinant adeno-associated virus (rAAV) attenuated the activation of p38 MAPK but not of ERK1/2. p38 MAPK activation by the CaR is likely to be protein kinase C (PKC) independent, in that the pan-PKC inhibitor GF109203X failed to abolish the high-Ca2+
o-induced phosphorylation of p38 MAPK. Consistently with our data on the activation of this kinase, we observed that inhibiting p38 MAPK blocked the activation of the CAKC induced by the specific pharmacological CaR activator NPS R-467. In contrast, inhibiting MEK1 only transiently inhibited the activation of this K+ channel by NPS R-467, despite the continued presence of the antagonist. Similarly to the lack of any effect of the PKC inhibitor on the activation of ERK1/2 and p38 MAPK, inhibiting PKC had no effect on NPS R-467-induced activation of this channel. Therefore, our data show that the CaR, acting via p38 MAPK, regulates a large-conductance CAKC in U87 cells, a process that is PKC independent. Large-conductance CAKCs play an important role in the regulation of cellular volume, so our results have important implications for glioma cell volume regulation.
KW - Calcimimetic
KW - Glioma
KW - Large-conductance K channel
KW - Protein kinase C
UR - http://www.scopus.com/inward/record.url?scp=0742322786&partnerID=8YFLogxK
U2 - 10.1002/jnr.10875
DO - 10.1002/jnr.10875
M3 - Journal article
C2 - 14743432
AN - SCOPUS:0742322786
SN - 0360-4012
VL - 75
SP - 491
EP - 498
JO - Journal of Neuroscience Research
JF - Journal of Neuroscience Research
IS - 4
ER -