Axon degeneration mechanisms: commonality amid diversity
A wide range of insults can trigger axon degeneration, and axons respond with diverse morphology, topology and speed. However, recent genetic, immunochemical, morphological and pharmacological investigations point to convergent degeneration mechanisms. The principal convergence points — poor axonal transport, mitochondrial dysfunction and an increase in intra-axonal calcium — have been identified by rescuing axons with the slow Wallerian degeneration gene (Wld S) and studies with blockers of sodium or calcium influx. By understanding how the pathways fit together, we can combine our knowledge of mechanisms, and potentially also treatment strategies, from different axonal disorders.