TY - JOUR
T1 - PKCβI mediates the inhibition of P2Y receptor-induced inositol phosphate formation in endothelial cells
AU - Chen, Bing C.
AU - Lin, Wan-Wan
PY - 1999
Y1 - 1999
N2 - 1. Bovine pulmonary artery endothelium (CPAE) expresses phospholipase C (PLC)-linked P2Y1 and P2Y2 receptors, for them 2-methylthio-ATP (2MeSATP) and UTP are respective agonists. Here, we have investigated the particular protein kinase C (PKC) isoform(s) responsible for the inhibition of P2Y1 and P2Y2 receptor-evoked inositol phosphate (IP) formation by phorbol 12-myristate 13-acetate (PMA). 2. Although short-term (20 min) pretreatment of cells with PMA attenuated 2MeSATP- and UTP-induced phosphoinositide (PI) breakdown, this inhibition was lost after 15 h. Preincubation with PMA for 24 h, on the contrary, potentiated 2MeSATP and UTP responses. The IP formation stimulated by NaF was unaltered by PMA pretreatment. 3. Western blot analysis showed that treatment of CPAE with PMA resulted in a rapid translocation of PKC isoform βI, ε and μ, but not λ, from the cytosol to the membrane fraction. 4. Pretreatment of the selective PKC inhibitor Ro 31-8220 attenuated the inhibitory effect of PMA on IP formation. Go 6976 (an inhibitor of conventional PKCα, β and γ) and LY 379196 (a selective PKCβ inhibitor) also dose-dependently inhibited the PMA-mediated desensitization. 5. Transfection of PKCβ-specific antisense oligonucleotide reduced PKCβI protein level and inhibited PMA-mediated PI reduction, 6. RT-PCR analysis showed that PMA treatment for 4-24 h up-regulated P2Y1 and P2Y2 receptors at the mRNA levels. 7. These results suggest that PKCβI may exert a negative feedback regulation on endothelial P2Y1 and P2Y1 receptor-mediated PI turnover. The down-regulation of PKCβI and enhanced P2Y receptor expression together might contribute to the late PI enhancing effect of PMA.
AB - 1. Bovine pulmonary artery endothelium (CPAE) expresses phospholipase C (PLC)-linked P2Y1 and P2Y2 receptors, for them 2-methylthio-ATP (2MeSATP) and UTP are respective agonists. Here, we have investigated the particular protein kinase C (PKC) isoform(s) responsible for the inhibition of P2Y1 and P2Y2 receptor-evoked inositol phosphate (IP) formation by phorbol 12-myristate 13-acetate (PMA). 2. Although short-term (20 min) pretreatment of cells with PMA attenuated 2MeSATP- and UTP-induced phosphoinositide (PI) breakdown, this inhibition was lost after 15 h. Preincubation with PMA for 24 h, on the contrary, potentiated 2MeSATP and UTP responses. The IP formation stimulated by NaF was unaltered by PMA pretreatment. 3. Western blot analysis showed that treatment of CPAE with PMA resulted in a rapid translocation of PKC isoform βI, ε and μ, but not λ, from the cytosol to the membrane fraction. 4. Pretreatment of the selective PKC inhibitor Ro 31-8220 attenuated the inhibitory effect of PMA on IP formation. Go 6976 (an inhibitor of conventional PKCα, β and γ) and LY 379196 (a selective PKCβ inhibitor) also dose-dependently inhibited the PMA-mediated desensitization. 5. Transfection of PKCβ-specific antisense oligonucleotide reduced PKCβI protein level and inhibited PMA-mediated PI reduction, 6. RT-PCR analysis showed that PMA treatment for 4-24 h up-regulated P2Y1 and P2Y2 receptors at the mRNA levels. 7. These results suggest that PKCβI may exert a negative feedback regulation on endothelial P2Y1 and P2Y1 receptor-mediated PI turnover. The down-regulation of PKCβI and enhanced P2Y receptor expression together might contribute to the late PI enhancing effect of PMA.
KW - 2MeSATP
KW - Endothelium
KW - P2 receptors
KW - PI turnover
KW - PKCβI
KW - Receptor up-regulation
KW - UTP
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U2 - 10.1038/sj.bjp.0702727
DO - 10.1038/sj.bjp.0702727
M3 - Article
C2 - 10482923
AN - SCOPUS:0032588150
VL - 127
SP - 1908
EP - 1914
JO - British Journal of Pharmacology
JF - British Journal of Pharmacology
SN - 0007-1188
IS - 8
ER -