Extracellular ATP stimulates increases in Na+/K+ pump activity, intracellular pH and uridine uptake in cultures of mammalian cells.
Using 3T3 and 3T6 mouse fibroblasts and A431 epidermoid carcinoma cells, we previously observed that extracellular ATP and ADP were mitogens and they synergized with other growth factors (Huang, N., Wang, D. and Heppel, L. A. (1989) Proc. Natl. Acad. Sci. USA 86, 7904-7908). We now report that ATP and ADP stimulated Na+ entry, intracellular alkalinization and Na+/K+ pump activity, which are early events that had been proposed to play a central role in DNA synthesis. In addition, ATP, ADP and AMPPNP stimulated uridine uptake by a pathway involving arachidonic acid metabolism. In A431 cells, activation of protein kinase C also contributed to ATP-dependent stimulation of uridine uptake. Concentrations of indomethacin and pertussis toxin which inhibited uridine uptake also blocked arachidonic acid metabolism and DNA synthesis. ATP acted as a competence factor. Interestingly, ATP did not have to be continuously present to stimulate uridine uptake. It was equally effective even when it was washed away after brief treatment of cells.
Huang
N N
NN
Section of Biochemistry, Molecular and Cell Biology, Cornell University, Ithaca, NY 14853.
Ahmed
A H
AH
Wang
D J
DJ
Heppel
L A
LA
D016475:3T3 Cells; D000244:Adenosine Diphosphate / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000494:pharmacology*; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002294:Carcinoma, Squamous Cell; D002460:Cell Line; D004815:Epidermal Growth Factor / Q000494:pharmacology; D006133:Growth Substances / Q000494:pharmacology*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007213:Indomethacin / Q000494:pharmacology; D007328:Insulin / Q000494:pharmacology; D007700:Kinetics; D051379:Mice; D037342:Pertussis Toxin; D015240:Phorbol 12,13-Dibutyrate / Q000494:pharmacology; D011188:Potassium / Q000378:metabolism*; D011493:Protein Kinase C / Q000378:metabolism; D012413:Rubidium / Q000378:metabolism; D012414:Rubidium Radioisotopes; D012964:Sodium / Q000378:metabolism*; D000254:Sodium-Potassium-Exchanging ATPase / Q000187:drug effects* / Q000502:physiology; D014529:Uridine / Q000378:metabolism*; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
D006133:Growth Substances; D007328:Insulin; D012414:Rubidium Radioisotopes; D010566:Virulence Factors, Bordetella; D015240:Phorbol 12,13-Dibutyrate; D000244:Adenosine Diphosphate; D004815:Epidermal Growth Factor; D000255:Adenosine Triphosphate; D012964:Sodium; D037342:Pertussis Toxin; D011493:Protein Kinase C; D000254:Sodium-Potassium-Exchanging ATPase; D012413:Rubidium; D011188:Potassium; D014529:Uridine; D007213:Indomethacin