Fused in sarcoma (FUS): an oncogene goes awry in neurodegeneration

Area of Science:

• Neuroscience
• Molecular Biology
• Genetics

Background:

• Fused in sarcoma (FUS) is a nuclear protein crucial for gene expression regulation.
• FUS mutations cause familial amyotrophic lateral sclerosis (ALS-FUS), leading to FUS cytosolic deposition.
• FUS and related FET proteins are found in cytoplasmic inclusions in frontotemporal lobar degeneration (FTLD-FUS).

Purpose of the Study:

• To summarize the physiological roles of FET proteins in the nucleus and cytoplasm.
• To review the distinct pathomechanisms of FUS deposition in ALS-FUS versus FTLD-FUS.
• To differentiate the molecular basis of ALS-FUS (FUS dysfunction) from FTLD-FUS (FET family dysfunction).

Main Methods:

• Literature review of FUS and FET protein functions.
• Analysis of pathomechanisms in neurodegenerative diseases (ALS-FUS, FTLD-FUS).
• Comparison of FUS deposition patterns in different disease contexts.

Main Results:

• FUS normally functions in the nucleus, regulating transcription, splicing, and mRNA transport.
• Cytosolic mislocalization of FUS in ALS-FUS suggests loss of nuclear function and/or gain of toxic cytoplasmic function.
• FTLD-FUS involves co-deposition of all three FET proteins, unlike the selective FUS deposition in ALS-FUS.

Conclusions:

• ALS-FUS likely results from a specific FUS protein dysfunction.
• FTLD-FUS may stem from a broader dysfunction affecting the entire FET protein family.
• Understanding these distinct mechanisms is key for neurodegeneration research, particularly concerning RNA and splicing regulation.