JUN and thanatophoric dysplasia: To examine the effect of Jasp treatment on TD-induced retrograde signaling in axon degeneration, we examined phosphorylation of c-Jun and found that application of Jasp prevented the TD-induced rise in phosphorylated c-Jun (p-c-Jun) (Figure 4C,D), which is required in part for TD-induced degeneration (Simon et al., 2016).