MST1 and scrapie: MST1, DLK and mitogen-activated protein kinase 9 (JNK2) (p54; α2/β2 isoforms), which clustered together because they were expressed to similarly lower levels in scrapie- than in mock-infected mice at 130 dpi, are all involved in an MST1 signaling pathway that promotes neuronal death (Figure 4B, ii).