P2X7-mediated ATP secretion is accompanied by depletion of cytosolic ATP

Purinergic Signal. 2019 Jun;15(2):155-166. doi: 10.1007/s11302-019-09654-5. Epub 2019 Apr 23.


ATP and its metabolites are important extracellular signal transmitters acting on purinergic P2 and P1 receptors. Most cells can actively secrete ATP in response to a variety of external stimuli such as gating of the P2X7 receptor. We used Yac-1 murine lymphoma cells to study P2X7-mediated ATP release. These cells co-express P2X7 and ADP-ribosyltransferase ARTC2, permitting gating of P2X7 by NAD+-dependent ADP-ribosylation without the need to add exogenous ATP. Yac-1 cells released ATP into the extracellular space within minutes after stimulation with NAD+. This was blocked by pre-incubation with the inhibitory P2X7-specific nanobody 13A7. Gating of P2X7 for 3 h significantly decreased intracellular ATP levels in living cells, but these had returned to normal by 20 h. P2X7-mediated ATP release was dependent on a rise in cytosolic calcium and the depletion of intracellular potassium, but was not blocked by inhibitors of pannexins or connexins. We used genetically encoded FRET-based ATP sensors targeted to the cytosol to image P2X7-mediated changes in the distribution of ATP in 3T3 fibroblasts co-expressing P2X7 and ARTC2 and in Yac-1 cells. In response to NAD+, we observed a marked depletion of ATP in the cytosol. This study demonstrates the potential of ATP sensors as tools to study regulated ATP release by other cell types under other conditions.

Keywords: ARTC2; ATP release; FRET; Lymphoma; Nanobodies; P2X7.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 3T3 Cells
  • Adenosine Triphosphate / metabolism*
  • Animals
  • Cell Line, Tumor
  • Cytosol / metabolism
  • Fluorescence Resonance Energy Transfer / methods
  • Mice
  • Receptors, Purinergic P2X7 / metabolism*


  • P2rx7 protein, mouse
  • Receptors, Purinergic P2X7
  • Adenosine Triphosphate