JAK1 palmitoylation by ZDHHC3/7 is Essential for Neuropoietic Cytokine Signaling and DRG Neuron Survival

Janus Kinase-1 (JAK1) plays key roles in pro-survival signaling during neurodevelopment and in responses to neuronal injury. JAK1 was identified as a potential palmitoyl-protein in high-throughput studies, but the importance of palmitoylation for roles of JAK1 in neurons has not been addressed. Here, we report that JAK1 is endogenously palmitoylated in cultured Dorsal Root Ganglion (DRG) neurons and, using an shRNA knockdown/rescue approach, reveal that JAK1 palmitoylation is important for neuropoietic cytokine-dependent signaling and neuronal survival. We further identify the related palmitoyl acyltransferases (PATs) ZDHHC3 and ZDHHC7 as dominant regulators of JAK1 palmitoylation in transfected non-neuronal cells and endogenously in neurons. At the molecular level, palmitoylation is critical for JAK1 kinase activity in transfected cells and even in vitro, likely because palmitoylation facilitates transphosphorylation of key sites in the JAK1 activation loop. These findings provide new insights into palmitoylation-dependent control of neuronal development and survival.