The C9orf72-interacting protein Smcr8 is a negative regulator of autoimmunity and lysosomal exocytosis

Yingying Zhang, Aaron Burberry, Jin Yuan Wang, Jackson Sandoe, Sulagna Ghosh, Namrata D. Udeshi, Tanya Svinkina, Daniel A. Mordes, Joanie Mok, Maura Charlton, Quan Zhen Li, Steven A. Carr, Kevin Eggan

Research output: Contribution to journalArticle

20 Scopus citations

Abstract

While a mutation in C9ORF72 is the most common genetic contributor to amyotrophic lateral sclerosis (ALS), much remains to be learned concerning the function of the protein normally encoded at this locus. To elaborate further on functions for C9ORF72, we used quantitative mass spectrometry-based proteomics to identify interacting proteins in motor neurons and found that its long isoform complexes with and stabilizes SMCR8, which further enables interaction with WDR41. To study the organismal and cellular functions for this tripartite complex, we generated Smcr8 loss-of-function mutant mice and found that they developed phenotypes also observed in C9orf72 loss-of-function animals, including autoimmunity. Along with a loss of tolerance for many nervous system autoantigens, we found increased lysosomal exocytosis in Smcr8 mutant macrophages. In addition to elevated surface Lamp1 (lysosome-associated membrane protein 1) expression, we also observed enhanced secretion of lysosomal components—phenotypes that we subsequently observed in C9orf72 loss-of-function macrophages. Overall, our findings demonstrate that C9ORF72 and SMCR8 have interdependent functions in suppressing autoimmunity as well as negatively regulating lysosomal exocytosis—processes of potential importance to ALS.

Original languageEnglish (US)
Pages (from-to)929-943
Number of pages15
JournalGenes and Development
Volume32
Issue number13-14
DOIs
StatePublished - Jul 1 2018

Keywords

  • Amyotrophic lateral sclerosis (ALS)
  • Autoimmunity
  • Autophagy
  • C9ORF72
  • Lysosome
  • SMCR8

ASJC Scopus subject areas

  • Genetics
  • Developmental Biology

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    Zhang, Y., Burberry, A., Wang, J. Y., Sandoe, J., Ghosh, S., Udeshi, N. D., Svinkina, T., Mordes, D. A., Mok, J., Charlton, M., Li, Q. Z., Carr, S. A., & Eggan, K. (2018). The C9orf72-interacting protein Smcr8 is a negative regulator of autoimmunity and lysosomal exocytosis. Genes and Development, 32(13-14), 929-943. https://doi.org/10.1101/gad.313932.118