Plekhg5-regulated autophagy of synaptic vesicles reveals a pathogenic mechanism in motoneuron disease

Nat Commun. 2017 Oct 30;8(1):678. doi: 10.1038/s41467-017-00689-z.


Autophagy-mediated degradation of synaptic components maintains synaptic homeostasis but also constitutes a mechanism of neurodegeneration. It is unclear how autophagy of synaptic vesicles and components of presynaptic active zones is regulated. Here, we show that Pleckstrin homology containing family member 5 (Plekhg5) modulates autophagy of synaptic vesicles in axon terminals of motoneurons via its function as a guanine exchange factor for Rab26, a small GTPase that specifically directs synaptic vesicles to preautophagosomal structures. Plekhg5 gene inactivation in mice results in a late-onset motoneuron disease, characterized by degeneration of axon terminals. Plekhg5-depleted cultured motoneurons show defective axon growth and impaired autophagy of synaptic vesicles, which can be rescued by constitutively active Rab26. These findings define a mechanism for regulating autophagy in neurons that specifically targets synaptic vesicles. Disruption of this mechanism may contribute to the pathophysiology of several forms of motoneuron disease.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Autophagy / genetics*
  • Cell Line
  • Cells, Cultured
  • Guanine Nucleotide Exchange Factors / genetics*
  • Guanine Nucleotide Exchange Factors / metabolism
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Mice, Transgenic
  • Microscopy, Electron, Transmission
  • Motor Neuron Disease / genetics*
  • Motor Neuron Disease / metabolism
  • Motor Neurons / metabolism
  • Presynaptic Terminals / metabolism
  • Synaptic Vesicles / metabolism*
  • Synaptic Vesicles / ultrastructure
  • rab GTP-Binding Proteins / genetics
  • rab GTP-Binding Proteins / metabolism


  • Guanine Nucleotide Exchange Factors
  • Rab26 protein, mouse
  • Syx protein, mouse
  • rab GTP-Binding Proteins