SPAST and hereditary spastic paraplegia: Moreover, in HSP the pathological gain of function of spastin could be counteracted by targeting the upstream mechanism of spastin recruitment to microtubules, i.e. (i) by inhibiting polyglutamylation by TTLLs or (ii) by increasing the deglutamylation by CCPs, or (iii) by targeting the binding of spastin to microtubules.