Proteomic analysis of FUS interacting proteins provides insights into FUS function and its role in ALS

• Published in: Biochimica et biophysica acta 2016-10, Vol.1862 (10), p.2004-2014
• Main Authors: Kamelgarn, Marisa, Chen, Jing, Kuang, Lisha, Arenas, Alexandra, Zhai, Jianjun, Zhu, Haining, Gal, Jozsef
• Format: Article
• Language: English
• Subjects: ALS; Amyotrophic Lateral Sclerosis - metabolism; Amyotrophic Lateral Sclerosis - pathology; Animals; Cell Line, Tumor; Exosomes - metabolism; Exosomes - pathology; FUS; HEK293 Cells; Heterogeneous Nuclear Ribonucleoprotein A1 - metabolism; Humans; Mice; Neurodegeneration; Nuclear Matrix-Associated Proteins - metabolism; Protein interaction network; Proteomics; RNA-Binding Protein FUS - metabolism; RNA-Binding Proteins - metabolism
• ISSN: 0925-4439; 0006-3002; 1879-260X
• DOI: 10.1016/j.bbadis.2016.07.015

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease. Mutations in the Fused in Sarcoma/Translocated in Liposarcoma (FUS/TLS) gene cause a subset of familial ALS cases and are also implicated in sporadic ALS. FUS is typically localized to the nucleus. The ALS-related FUS mutations cause cytoplasmic mis-localization and the formation of stress granule-like structures. Abnormal cytoplasmic FUS localization was also found in a subset of frontotemporal dementia (FTLD) cases without FUS mutations. To better understand the function of FUS, we performed wild-type and mutant FUS pull-downs followed by proteomic identification of the interacting proteins. The FUS interacting partners we identified are involved in multiple pathways, including chromosomal organization, transcription, RNA splicing, RNA transport, localized translation, and stress response. FUS interacted with hnRNPA1 and Matrin-3, RNA binding proteins whose mutations were also reported to cause familial ALS, suggesting that hnRNPA1 and Matrin-3 may play common pathogenic roles with FUS. The FUS interactions displayed varied RNA dependence. Numerous FUS interacting partners that we identified are components of exosomes. We found that FUS itself was present in exosomes, suggesting that the secretion of FUS might contribute to the cell-to-cell spreading of FUS pathology. FUS interacting proteins were sequestered into the cytoplasmic mutant FUS inclusions that could lead to their mis-regulation or loss of function, contributing to ALS pathogenesis. Our results provide insights into the physiological functions of FUS as well as important pathways where mutant FUS can interfere with cellular processes and potentially contribute to the pathogenesis of ALS. •We performed proteomic analysis of FUS interacting proteins from human cells.•FUS interacts with numerous regulators of gene expression and RNA metabolism.•The interactions were differentially impacted by RNase treatment.•FUS interacted with Matrin-3 and hnRNPA1, proteins also involved in ALS pathogenesis.•FUS interacted with numerous exosome components and was itself secreted by exosomes.