Differential effects of activation of protein kinase C and cyclic-AMP-dependent protein kinase on sodium-dependent phosphate uptake in NIH 3T3 cells.
Activation of protein kinase C (PKC) by phorbol ester (PMA), or by diacylglycerol analogue (OAG) treatment of NIH 3T3 cells resulted in the rapid (within 2-5 min) stimulation (approx. 2-fold) of sodium-dependent phosphate (Pi) transport. Conversely, preincubation of these cells with forskolin and cholera toxin, or incubation with 8-bromo-cAMP, to activate cAMP-dependent protein kinase (PKA), resulted in a decrease in Na+/Pi transport. Activation of either PKC or PKA did not change the Vmax of Pi uptake. However, activation of PKC did result in an increase, while activation of PKA caused a decrease, in the affinity for Pi. These results indicate that there is differential regulation of Na+/Pi uptake in NIH 3T3 cells by activators of PKC (stimulated) and PKA (inhibited) as a consequence of changes in the affinity of the transporter for Pi.
Oláh
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Laboratory of Cellular Oncology, National Cancer Institute, National Institutes of Health, Bethesda 20892.
Lehel
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C
Anderson
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WB
D016475:3T3 Cells / Q000187:drug effects / Q000378:metabolism; D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology; D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism; D002772:Cholera Toxin / Q000494:pharmacology; D005576:Colforsin / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D007700:Kinetics; D051379:Mice; D008954:Models, Biological; D028044:Phosphate-Binding Proteins; D010710:Phosphates / Q000378:metabolism*; D011493:Protein Kinase C / Q000378:metabolism*; D047428:Protein Kinase Inhibitors; D011494:Protein Kinases / Q000378:metabolism*; D015398:Signal Transduction; D012964:Sodium / Q000494:pharmacology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D013997:Time Factors
D002352:Carrier Proteins; D028044:Phosphate-Binding Proteins; D010710:Phosphates; D047428:Protein Kinase Inhibitors; D005576:Colforsin; D015124:8-Bromo Cyclic Adenosine Monophosphate; D002772:Cholera Toxin; D012964:Sodium; D011494:Protein Kinases; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate