Interestingly, BMP signalling has been shown to regulate MT stability and axonal transport homeostasis in Drosophila motor neurons (Wang et al., 2007; Nahm et al., 2013), two crucial processes in spastin-related HSP pathogenesis (Tarrade et al., 2006; Fassier et al., 2013; Denton et al., 2014; Havlicek et al., 2014). The gene discussed is SPAST; the disease is hereditary spastic paraplegia.