Aggregation of ALS-linked FUS mutant sequesters RNA binding proteins and impairs RNA granules formation - PubMed (original) (raw)

. 2014 Sep 26;452(3):600-7.

doi: 10.1016/j.bbrc.2014.08.115. Epub 2014 Aug 28.

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Aggregation of ALS-linked FUS mutant sequesters RNA binding proteins and impairs RNA granules formation

Keisuke Takanashi et al. Biochem Biophys Res Commun. 2014.

Abstract

Protein aggregate/inclusion is one of hallmarks for neurodegenerative disorders including amyotrophic lateral sclerosis (ALS). FUS/TLS, one of causative genes for familial ALS, encodes a multifunctional DNA/RNA binding protein predominantly localized in the nucleus. C-terminal mutations in FUS/TLS cause the retention and the inclusion of FUS/TLS mutants in the cytoplasm. In the present study, we examined the effects of ALS-linked FUS mutants on ALS-associated RNA binding proteins and RNA granules. FUS C-terminal mutants were diffusely mislocalized in the cytoplasm as small granules in transiently transfected SH-SY5Y cells, whereas large aggregates were spontaneously formed in ∼10% of those cells. hnRNP A1, hnRNP A2, and SMN1 as well as FUS wild type were assembled into stress granules under stress conditions, and these were also recruited to FUS mutant-derived spontaneous aggregates in the cytoplasm. These aggregates stalled poly(A) mRNAs and sequestered SMN1 in the detergent insoluble fraction, which also reduced the number of nuclear oligo(dT)-positive foci (speckles) in FISH (fluorescence in situ hybridization) assay. In addition, the number of P-bodies was decreased in cells harboring cytoplasmic granules of FUS P525L. These findings raise the possibility that ALS-linked C-terminal FUS mutants could sequester a variety of RNA binding proteins and mRNAs in the cytoplasmic aggregates, which could disrupt various aspects of RNA equilibrium and biogenesis.

Keywords: ALS; FUS/TLS; SMN1; hnRNP A/B.

Copyright © 2014 Elsevier Inc. All rights reserved.

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