1. ALS/FTD-causing mutation in cyclin F causes the dysregulation of SFPQ
- Author
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Shu Yang, Alana De Luca, Flora Cheng, Alison L. Hogan, Lars M. Ittner, Mark P. Molloy, Bingyang Shi, Natalie Grima, Ian P. Blair, Yazi D. Ke, Roger S. Chung, Jennilee M. Davidson, Stephanie L. Rayner, Albert Lee, Marco Morsch, and Carol G. Au
- Subjects
Protein degradation ,medicine.disease_cause ,DNA-binding protein ,03 medical and health sciences ,Splicing factor ,Protein Aggregates ,0302 clinical medicine ,Cyclins ,Genetics ,medicine ,Missense mutation ,Humans ,Protein Interaction Maps ,RNA Processing, Post-Transcriptional ,PTB-Associated Splicing Factor ,Molecular Biology ,Genetics (clinical) ,030304 developmental biology ,Cyclin ,0303 health sciences ,Mutation ,biology ,HEK 293 cells ,Amyotrophic Lateral Sclerosis ,RNA-Binding Proteins ,General Medicine ,Ubiquitin ligase ,Cell biology ,DNA-Binding Proteins ,HEK293 Cells ,Frontotemporal Dementia ,Proteolysis ,biology.protein ,RNA ,030217 neurology & neurosurgery - Abstract
Previously, we identified missense mutations in CCNF that are causative of familial and sporadic amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Hallmark features of these diseases include the build-up of insoluble protein aggregates as well as the mislocalization of proteins such as transactive response DNA binding protein 43 kDa (TDP-43). In recent years, the dysregulation of SFPQ (splicing factor proline and glutamine rich) has also emerged as a pathological hallmark of ALS/FTD. CCNF encodes for the protein cyclin F, a substrate recognition component of an E3 ubiquitin ligase. We have previously shown that ALS/FTD-linked mutations in CCNF cause disruptions to overall protein homeostasis that leads to a build-up of K48-linked ubiquitylated proteins as well as defects in autophagic machinery. To investigate further processes that may be affected by cyclin F, we used a protein-proximity ligation method, known as Biotin Identification (BioID), standard immunoprecipitations and mass spectrometry to identify novel interaction partners of cyclin F and infer further process that may be affected by the ALS/FTD-causing mutation. Results demonstrate that cyclin F closely associates with proteins involved with RNA metabolism as well as a number of RNA-binding proteins previously linked to ALS/FTD, including SFPQ. Notably, the overexpression of cyclin F(S621G) led to the aggregation and altered subcellular distribution of SFPQ in human embryonic kidney (HEK293) cells, while leading to altered degradation in primary neurons. Overall, our data links ALS/FTD-causing mutations in CCNF to converging pathological features of ALS/FTD and provides a link between defective protein degradation systems and the pathological accumulation of a protein involved in RNA processing and metabolism.
- Published
- 2020