MAP2K4 and proximal spinal muscular atrophy: Recently, Genabai et al. (2015) reported that the c-Jun NH2-terminal kinase (JNK) cascades ASK1/MKK4/7/JNK and MEKK1/MKK4/7/JNK are activated in spinal cord of SMA mice (SMNΔ7) and patients (Genabai et al., 2015): in particular, an increase in phosphorylation of the three JNK isoforms (JNK1, 2, 3) was visible in SMA phenotype and the brain-specific isoform JNK isoform 3 (JNK3) mediated the neurodegeneration caused by the low levels of SMN.