Rapid depletion of ESCRT protein Vps4 underlies injury-induced autophagic impediment and Wallerian degeneration.

Abstract

Injured axons undergo a controlled, self-destruction process, known as Wallerian degeneration. However, the underlying mechanism remains elusive. Using the <i>Drosophila</i> wing nerve as a model, we identify the ESCRT component <i>Vps4</i> as a previously unidentified essential gene for axonal integrity. Up-regulation of <i>Vps4</i> remarkably delays degeneration of injured axons. We further reveal that <i>Vps4</i> is required and sufficient to promote autophagic flux in axons and mammalian cells. Moreover, using both in vitro and in vivo models, we show that the function of <i>Vps4</i> in maintaining axonal autophagy and suppressing Wallerian degeneration is conserved in mammals. Last, we uncover that Vps4 protein is rapidly depleted in injured mouse axons, which may underlie the injury-induced autophagic impediment and the subsequent axonal degeneration. Together, Vps4 and ESCRT may represent a novel signal transduction mechanism in axon injury and Wallerian degeneration.