FUS (Fused in Sarcoma) proteinopathy represents a critical pathological hallmark in a subset of neurodegenerative diseases, particularly Amyotrophic Lateral Sclerosis (ALS) and Frontotemporal Dementia (FTD). FUS Proteinopathy Neurons are characterized by the accumulation of misfolded FUS protein in the cytoplasm, leading to disruption of normal cellular functions and ultimately neuronal death[1][2].
This page provides comprehensive information about FUS-positive neurons, their molecular mechanisms, genetic contributors, and therapeutic strategies targeting this pathology.
Neurons exhibiting FUS proteinopathy feature cytoplasmic inclusions of mutated or mislocalized FUS protein. FUS mutations are responsible for approximately 5% of familial ALS cases and up to 10% of juvenile-onset ALS[3]. Unlike TDP-43 proteinopathy, which is the most common pathology in sporadic ALS, FUS pathology is associated with specific genetic subtypes and distinct clinical phenotypes.
The FUS protein is a member of the FET (FUS, EWSR1, TAF15) family of RNA-binding proteins, which are involved in multiple aspects of RNA metabolism including transcription, splicing, transport, and translation[4].
FUS (Fused in Sarcoma), also known as TLS (Translocated in Sarcoma), is a 526-amino acid nuclear protein with multiple functional domains:
In healthy neurons, FUS performs critical functions[5]:
The transition from normal FUS function to pathological aggregation involves several key steps[6]:
Over 50 FUS mutations have been identified in ALS and FTD patients[7]:
| Mutation | Protein Change | Clinical Phenotype | Notes |
|---|---|---|---|
| R521C | Arginine → Cysteine | ALS | Most common FUS mutation |
| R521G | Arginine → Glycine | ALS | Second most common |
| R522G | Arginine → Glycine | ALS | |
| P525L | Proline → Leucine | Juvenile ALS | Severe, rapid progression |
| P525R | Proline → Arginine | Juvenile ALS | Very aggressive |
| R487L | Arginine → Leucine | FTD | |
| R487Q | Arginine → Glutamine | FTD/ALS | |
| G507D | Glycine → Aspartic Acid | ALS | |
| H517Q | Histidine → Glutamine | ALS |
FUS proteinopathy preferentially affects specific neuronal populations[8]:
FUS proteinopathy disrupts multiple aspects of RNA metabolism[9]:
Alternative Splicing Aberrations
mRNA Transport Impairment
Translation Dysregulation
Stress granules are membrane-less organelles that form under cellular stress[10]:
Normal Stress Granule Function
Pathological Granule Dynamics in FUS Proteinopathy
FUS mutations disrupt nuclear-cytoplasmic transport[11]:
FUS plays a direct role in DNA repair[12]:
Impaired DNA Damage Response
Genomic Instability
FUS pathology affects mitochondrial health[13]:
ASOs represent the most promising targeted approach[14]:
Localization Modulators
Stress Granule Modulators
RNA Processing Modulators
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Kwiatkowski TJ Jr et al. (2009) Mutations in the FUS/TLS gene on chromosome 16 cause familial amyotrophic lateral sclerosis. 2009. ↩︎
Vance C et al. (2009) Mutations in FUS, an RNA processing protein, cause familial amyotrophic lateral sclerosis type 6. 2009. ↩︎
Shang Y, Huang EJ (2016) Mechanisms of FUS mutations in dietary amyotrophic lateral sclerosis. Brain Res. 2016;1647:65-78. 2016. ↩︎
Dormann D, Haass C (2011) TDP-43 and FUS: a nuclear affair. Trends Neurosci. 2011;34(7):339-348. 2011. ↩︎
Ito D, Hatakeyama J (2022) FUS: Structure and Function in RNA Metabolism and Neurological Disease. Neurochem Int. 2022;158:105382. 2022. ↩︎
Liu Y et al. (2023) The molecular pathogenesis of FUS-associated ALS/FTD. 2023. ↩︎
Lenz G, McAlonis-Downes M (2023) FUS mutations in ALS and FTD: Clinical features and therapeutic approaches. Neurotherapeutics. 2023;20(2):305-318. 2023. ↩︎
Neumann M et al. (2009) FET proteins are major components of neuronal cytoplasmic inclusions in motor neuron disease. 2009. ↩︎
Ho WY et al. (2022) FUS-mediated dysregulation of RNA metabolism in ALS. 2022. ↩︎
Dao TP et al. (2021) FUS phase separation is modulated by molecular interactions and ATP. 2021. ↩︎
Japtok J et al. (2022) Dysregulation of nucleocytoplasmic transport in FUS-ALS. 2022. ↩︎
Wang H et al. (2023) FUS deficiency leads to DNA damage accumulation and neurodegeneration. 2023. ↩︎
Tradewell ML et al. (2022) Mitochondrial dysfunction in FUS-ALS. 2022. ↩︎
Bhattacharya S et al. (2024) Antisense oligonucleotide therapy for FUS-ALS: Current status and future directions. 2024. ↩︎