RT Journal Article SR Electronic T1 ATP triggers macropinocytosis that internalizes and is regulated by PANX1 JF bioRxiv FD Cold Spring Harbor Laboratory SP 2020.11.19.389072 DO 10.1101/2020.11.19.389072 A1 Andrew K.J. Boyce A1 Emma van der Slagt A1 Juan C. Sanchez-Arias A1 Leigh Anne Swayne YR 2020 UL http://biorxiv.org/content/early/2020/11/20/2020.11.19.389072.abstract AB Macropinocytosis is an endocytic process that allows cells to respond to changes in their environment by internalizing nutrients and cell surface proteins, as well as modulating cell size. Here, we identify that adenosine triphosphate (ATP) triggers macropinocytosis in murine neuroblastoma cells, thereby internalizing the ATP release channel pannexin 1 (PANX1) while concurrently increasing cross-sectional cellular area. Amiloride, a potent inhibitor of macropinocytosis-associated GTPases, abolished ATP-induced PANX1 internalization and cell area expansion. Transient expression of the GTP-hydrolysis resistant GTPase ARF6 Q67L led to increased PANX1 internalization and increased cell area equivalent to levels seen with ATP stimulation. Mutation of an extracellular tryptophan (W74) in PANX1 abolished ATP-evoked cell area enlargement suggesting that PANX1 regulates this form of macropinocytosis. This novel role of PANX1 in macropinocytosis could be particularly important for disease states implicating PANX1, such as cancer, where ATP can act as a purinergic regulator of cell growth/metastasis and as a supplementary energy source following internalization.Competing Interest StatementThe authors have declared no competing interest.