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Genes Dev DOI:10.1101/gad.313932.118

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

Publication TypeJournal Article
Year of Publication2018
AuthorsZhang, Y, Burberry, A, Wang, J-Y, Sandoe, J, Ghosh, S, Udeshi, ND, Svinkina, T, Mordes, DA, Mok, J, Charlton, M, Li, Q-Z, Carr, SA, Eggan, K
JournalGenes Dev
Date Published2018 07 01
KeywordsAmyotrophic Lateral Sclerosis, Animals, Autoimmunity, C9orf72 Protein, Carrier Proteins, Exocytosis, Gene Expression Regulation, Humans, Lymph Nodes, Lysosomal-Associated Membrane Protein 1, Lysosomes, Macrophages, Mice, Mice, Knockout, Mutation, Protein Isoforms, Protein Stability, Splenomegaly

While a mutation in 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 loss-of-function mutant mice and found that they developed phenotypes also observed in loss-of-function animals, including autoimmunity. Along with a loss of tolerance for many nervous system autoantigens, we found increased lysosomal exocytosis in 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 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.


Alternate JournalGenes Dev
PubMed ID29950492
PubMed Central IDPMC6075033
Grant ListR01 NS089742 / NS / NINDS NIH HHS / United States