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HuR prevents amyloid beta-induced phase separation of miRNA-bound Ago2 to RNA-processing bodies

Sritama Ray1, Sumangal Roychowdhury2, Yogaditya Chakrabarty3

  • 1RNA Biology Research Laboratory, Molecular Genetics Division, CSIR-Indian Institute of Chemical Biology, Kolkata 700032, India.

Structure (London, England : 1993)
|March 8, 2025
PubMed

Insights

MicroRNA binding to Ago2 protein is crucial for its localization to RNA-processing bodies (P-bodies). This process is ATP-dependent and influenced by salt concentration, osmolarity, and other proteins.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Biochemistry

Background:

  • Membrane-less organelles regulate cellular activities through phase separation.
  • RNA-processing bodies (P-bodies) sequester miRNA-repressed mRNAs and Ago proteins.
  • Ago2 protein is essential for miRNA-mediated gene silencing and P-body localization.

Purpose of the Study:

  • To investigate the factors controlling Ago2 and miRNA-repressed mRNA compartmentalization into P-bodies.
  • To establish an in vitro system for observing Ago2 phase separation into P-bodies.

Main Methods:

  • Development of a detergent-permeabilized cell-based assay system.
  • Observation of in vitro phase separation of exogenously added Ago2 into P-bodies.
  • Analysis of the effects of miRNA binding, ATP, osmolarity, salt concentration, amyloid beta oligomers, and HuR on Ago2 localization.

Main Results:

  • miRNA binding to Ago2 is essential for its P-body localization.
  • Ago2 localization to P-bodies is an ATP-dependent process.
  • Osmolarity, salt concentration, amyloid beta oligomers, and HuR protein modulate Ago2 compartmentalization.

Conclusions:

  • Ago2-miRNA complex formation is critical for P-body targeting.
  • Cellular conditions and specific protein interactions significantly influence Ago2 phase separation and P-body localization.
  • Amyloid beta enhances Ago2 targeting, while HuR disrupts it by sequestering miRNAs.
Keywords:
Ago2HuRRNA binding proteinsRNA granulesRNA processing bodyamyloid betaliquid-liquid phase separationmiRNAneuroinflammation

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