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Amyotrophic Lateral Sclerosis-Associated Mutants of SOD1 Modulate miRNA Biogenesis through Aberrant Interactions with Exportin 5.

Xingyuan ChenXiaomei HeYen-Yu YangYinsheng Wang
Published in: ACS chemical biology (2022)
Mutations in the SOD 1 (superoxide dismutase 1) gene are associated with amyotrophic lateral sclerosis (ALS), a fatal neurodegenerative disease. By employing ascorbate peroxidase-based proximity labeling, coupled with LC-MS/MS analysis, we uncovered 43 and 24 proteins exhibiting higher abundance in the proximity proteomes of SOD1 G85R and SOD1 G93A , respectively, than that of wild-type SOD1. Immunoprecipitation followed by western blot analysis indicated the preferential binding of one of these proteins, exportin 5 (XPO5), toward the two mutants of SOD1 over the wild-type counterpart. In line with the established function of XPO5 in pre-miRNA transport, we observed diminished nucleocytoplasmic transport of pre-miRNAs in cells with ectopic expression of the two SOD1 mutants over those expressing the wild-type protein. On the other hand, RT-qPCR results revealed significant elevations in mature miRNA in cells expressing the two SOD1 mutants, which are attributed to the diminished inhibitory effect of XPO5 on Dicer-mediated cleavage of pre-miRNA to mature miRNA. Together, our chemoproteomic approach led to the revelation of a novel mechanism through which ALS-associated mutants of SOD1 perturb miRNA biogenesis, that is, through aberrant binding toward XPO5.
Keyphrases
  • amyotrophic lateral sclerosis
  • wild type
  • induced apoptosis
  • cell cycle arrest
  • hydrogen peroxide
  • gene expression
  • dna binding
  • oxidative stress
  • transcription factor
  • cell proliferation
  • small molecule
  • pi k akt