A metastasis-associated Pannexin1 mutant (Panx1 ) forms a minimalist ATP release channel.

A truncated form of the ATP release channel pannexin 1 (Panx1), Panx1 , is enriched in metastatic breast cancer cells and has been proposed to mediate metastatic cell survival by increasing ATP release through mechanosensitive Panx1 channels. However, whether Panx1 on its own (without the presence of wtPanx1) mediates ATP release has not been tested. Here, we show that Panx1 by itself can form a constitutively active membrane channel, capable of releasing ATP even in the absence of wild type Panx1.