Loss of the E3 ubiquitin ligase LRSAM1 sensitizes peripheral axons to degeneration in a mouse model of Charcot-Marie-Tooth disease

Dis Model Mech. 2013 May;6(3):780-92. doi: 10.1242/dmm.010942. Epub 2013 Mar 8.

Abstract

Charcot-Marie-Tooth disease (CMT) is a clinically and genetically heterogeneous condition characterized by peripheral axon degeneration with subsequent motor and sensory deficits. Several CMT gene products function in endosomal sorting and trafficking to the lysosome, suggesting that defects in this cellular pathway might present a common pathogenic mechanism for these conditions. LRSAM1 is an E3 ubiquitin ligase that is implicated in this process, and mutations in LRSAM1 have recently been shown to cause CMT. We have generated mouse mutations in Lrsam1 to create an animal model of this form of CMT (CMT2P). Mouse Lrsam1 is abundantly expressed in the motor and sensory neurons of the peripheral nervous system. Both homozygous and heterozygous mice have largely normal neuromuscular performance and only a very mild neuropathy phenotype with age. However, Lrsam1 mutant mice are more sensitive to challenge with acrylamide, a neurotoxic agent that causes axon degeneration, indicating that the axons in the mutant mice are indeed compromised. In transfected cells, LRSAM1 primarily localizes in a perinuclear compartment immediately beyond the Golgi and shows little colocalization with components of the endosome to lysosome trafficking pathway, suggesting that other cellular mechanisms also merit consideration.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acrylamide / pharmacology
  • Animals
  • Axons / drug effects
  • Axons / metabolism*
  • Behavior, Animal / drug effects
  • Cell Line
  • Charcot-Marie-Tooth Disease / complications
  • Charcot-Marie-Tooth Disease / enzymology*
  • Charcot-Marie-Tooth Disease / pathology
  • Disease Models, Animal
  • Endosomes / drug effects
  • Endosomes / metabolism
  • Humans
  • Lysosomes / drug effects
  • Lysosomes / metabolism
  • Mice
  • Mice, Mutant Strains
  • Mutagenesis / genetics
  • Mutation / genetics
  • Nerve Degeneration / complications
  • Nerve Degeneration / enzymology
  • Nerve Degeneration / pathology*
  • Neuromuscular Junction / drug effects
  • Neuromuscular Junction / metabolism
  • Neuromuscular Junction / pathology
  • Peripheral Nervous System / drug effects
  • Peripheral Nervous System / enzymology
  • Peripheral Nervous System / pathology*
  • Phenotype
  • Protein Transport / drug effects
  • Subcellular Fractions / drug effects
  • Subcellular Fractions / enzymology
  • Transfection
  • Ubiquitin-Protein Ligases / metabolism*

Substances

  • Acrylamide
  • LRSAM1 protein, mouse
  • Ubiquitin-Protein Ligases