Headline: Axonal Transport Pathology in ALS8 and Dynactin Mutations: Implications for Motor Neuron Survival
Introduction: Motor neurons possess extraordinarily long axons that depend entirely on robust intracellular transport machinery to sustain metabolic health. Mutations in genes regulating endoplasmic reticulum (ER)-Golgi transport (VAPB in ALS8) and retrograde microtubule motors (Dynactin) directly disrupt axonal traffic, precipitating neurodegeneration.
Pathological Mechanisms:
ALS8 (VAPB / 20q13): Encodes vesicle-associated membrane protein-associated protein B/C, disrupting ER-Golgi trafficking and presenting with late-onset spinal muscular atrophy (Finkel type SMA IV) or progressive motor neuron disease.
Dynactin (DCTN1 / 2p13): Mutations in the p150Glued subunit of the dynactin-dynein retrograde motor complex impair binding to microtubules, frequently heralding disease onset with early vocal cord paralysis and slow progression.