Synergistic effects of adenosine A1 and P2Y receptor stimulation on calcium mobilization and PKC translocation in DDT1 MF-2 cells.
1. The effect of adenosine analogues and of nucleotides, alone or in combination, on intracellular calcium, accumulation of inositol (1,4,5) trisphosphate (InsP3), and on activation of protein kinase C (PKC) was studied in DDT1 MF2 cells derived from a Syrian hamster myosarcoma. These cells were found to express mRNA for A1 and some as yet unidentified P2Y receptor(s). 2. Activation of either receptor type stimulated the production of InsP3 and raised intracellular calcium in DDT1 MF2 cells. Similarly, the A1 selective agonist N6-cyclopentyladenosine (CPA) increased PKC-dependent phosphorylation of the substrate MBP(4-14) and induced a PKC translocation to the plasma membrane as determined using [3H]-phorbol dibutyrate (PDBu) binding in DDT1 MF-2 cells. However, neither adenosine nor CPA induced a significant translocation of transiently transfected gamma-PKC-GFP from the cytosol to the cell membrane. In contrast to adenosine analogues, ATP and UTP also caused a rapid but transient translocation of gamma-PKC-GFP and activation of PKC. 3. Doses of the A1 agonist CPA and of ATP or UTP per se caused barely detectable increases in intracellular Ca2+ but when combined, they caused an almost maximal stimulation. Similarly, adenosine (0.6 microM) and UTP (or ATP, 2.5 microM), which per se caused no detectable translocation of either gamma- or epsilon-PKC-GFP, caused when combined a very clear-cut translocation of both PKC subforms, albeit with different time courses. These results show that simultaneous activation of P2Y and adenosine A1 receptors synergistically increases Ca2+ transients and translocation of PKC in DDT1 MF-2 cells. Since adenosine is rapidly formed by breakdown of extracellular ATP, such interactions may be biologically important.
Fredholm
Bertil B
BB
Department of Physiology and Pharmacology, Section of Molecular Neuropharmacology, Karolinska Institute, S-171 77 Stockholm, Sweden. bertil.fredholm@fyfa.ki.se
Assender
Jean W
JW
Irenius
Eva
E
Kodama
Noriko
N
Saito
Naoaki
N
D000241:Adenosine / Q000031:analogs & derivatives / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000378:metabolism / Q000494:pharmacology; D000818:Animals; D020013:Calcium Signaling / Q000187:drug effects* / Q000502:physiology; D002462:Cell Membrane / Q000187:drug effects* / Q000201:enzymology; D006224:Cricetinae; D004357:Drug Synergism; D049452:Green Fluorescent Proteins; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism; D007424:Intracellular Fluid / Q000187:drug effects / Q000378:metabolism; D008164:Luminescent Proteins; D032389:Myocytes, Smooth Muscle / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology; D020033:Protein Isoforms / Q000187:drug effects / Q000378:metabolism; D011493:Protein Kinase C / Q000187:drug effects* / Q000378:metabolism; D021381:Protein Transport / Q000187:drug effects / Q000502:physiology; D058906:Purinergic P1 Receptor Agonists; D018047:Receptors, Purinergic P1 / Q000378:metabolism; D018048:Receptors, Purinergic P2 / Q000187:drug effects* / Q000378:metabolism; D058472:Receptors, Purinergic P2Y1; D011993:Recombinant Fusion Proteins / Q000494:pharmacology; D014407:Tumor Cells, Cultured; D014544:Uridine Triphosphate / Q000378:metabolism / Q000494:pharmacology
D008164:Luminescent Proteins; D020033:Protein Isoforms; D058906:Purinergic P1 Receptor Agonists; D018047:Receptors, Purinergic P1; D018048:Receptors, Purinergic P2; D058472:Receptors, Purinergic P2Y1; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; D015544:Inositol 1,4,5-Trisphosphate; D000255:Adenosine Triphosphate; D011493:Protein Kinase C; D000241:Adenosine; D014544:Uridine Triphosphate