The beta-isoform of p38 mitogen-activated protein kinase (MAPK) also inhibits both anterograde and retrograde FAT in isolated squid axoplasm12, and ALS-related forms of ALS have been shown to inhibit FAT through a mechanism involving p38 activation10, 12, 20, prompting us to evaluate the potential role of this kinase. The gene discussed is MAPK14; the disease is amyotrophic lateral sclerosis.