Proteins in aggregates functionally impact multiple neurodegenerative disease models by forming proteasome-blocking...

Area of Science:

• Neurobiology
• Proteomics
• Aging Research

Background:

• Age-dependent neurodegenerative diseases are characterized by protein aggregate formation.
• These aggregates contain both shared and disease-specific proteins.
• Identifying common aggregation-promoting proteins across diverse neuropathies is crucial.

Purpose of the Study:

• To investigate if diverse neuropathies share additional aggregation-prone proteins.
• To identify these proteins using proteomics in a model organism.
• To assess the role of identified proteins in aggregation and cytotoxicity.

Main Methods:

• Utilized Caenorhabditis elegans models expressing polyglutamine (Q40::YFP) or amyloid-beta (Aβ₁₋₄₂).
• Isolated protein aggregates using antibody-coupled magnetic beads.
• Characterized aggregates via high-resolution mass spectrometry and RNA interference (RNAi) knockdown.

Main Results:

• Identified three Q40::YFP-associated proteins promoting aggregation and cytotoxicity.
• Knockdown of CRAM-1 (a key modulator) significantly reduced Q40::YFP and Aβ₁₋₄₂ aggregates.
• CRAM-1 knockdown also slowed age-dependent paralysis in Aβ₁₋₄₂ models and extended lifespan in wild-type worms.

Conclusions:

• CRAM-1 promotes protein aggregation by interfering with proteasomal degradation.
• CRAM-1 acts as a primitive chaperone, initially beneficial but ultimately detrimental to aggregate clearance.
• Targeting CRAM-1 may offer therapeutic strategies for age-dependent neurodegenerative diseases.