ATF2 phosphorylation is a core transcriptional driver of neuron apoptosis

Apoptotic neuron death is a key feature of neurodegenerative disease. Considerable efforts have been made to target this pathway but the molecular mechanisms remain incompletely understood. Here, we conducted an unbiased whole genome CRISPR inhibition screen in human neurons to discover genes required for their death and identified known targets including the kinase MAP3K12 (DLK) and the transcription factor JUN. In addition, this screen revealed a potential role for the transcription factor ATF2. We demonstrate that ATF2 phosphorylation by MAP3 kinases is the core driver of the pro-apoptotic transcriptional response. Surprisingly, JUN phosphorylation is not required for apoptosis. However, the phosphorylation of ATF2 and upregulation of JUN expression are crucial. ATF2 therefore converts the kinase signal into a transcriptional response. Inhibiting ATF2 in cultured human neurons prevents cell death. Notably we show that ATF2 knockdown is neuroprotective in injury models in vivo. Thus, ATF2 provides a promising new target for a wide range of neurodegenerative disorders.