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PRMT1 is required for RAP55 to localize to processing bodies

Ken Matsumoto1, Hiroshi Nakayama, Mami Yoshimura

  • 1Molecular Entomology Laboratory, RIKEN Advanced Science Institute, Wako, Saitama, Japan. matsumok@riken.jp

RNA Biology
|May 23, 2012
PubMed

Insights

RAP55 proteins are crucial for forming cytoplasmic messenger ribonucleoprotein (mRNP) granules in eukaryotic cells. Protein arginine methyltransferase 1 (PRMT1) is essential for RAP55A localization to processing bodies (P-bodies).

Area of Science:

  • Cell Biology
  • Molecular Biology
  • RNA Biology

Background:

  • Messenger ribonucleoproteins (mRNPs) form cytoplasmic granules like processing bodies (P-bodies) and stress granules (SGs).
  • RAP55A, an RNA-binding protein, is a translational repressor found in P-bodies and SGs.

Purpose of the Study:

  • To investigate the role of RAP55 proteins in the assembly of cytoplasmic mRNP granules.
  • To determine the involvement of protein arginine methyltransferases (PRMTs) in RAP55A localization and mRNP granule formation.

Main Methods:

  • Expression of RAP55A and RAP55B in human cultured cells.
  • Analysis of mRNP granule composition and localization using microscopy.
  • Investigating protein-protein interactions between RAP55A and PRMT1/PRMT5.
  • RNA interference (siRNA) to knock down PRMT1 expression.

Main Results:

  • RAP55B, like RAP55A, localizes to P-bodies.
  • Overexpression of RAP55A or RAP55B induces the formation of large, SG-like mRNP granules containing both P-body and SG components.
  • RAP55A interacts with PRMT1 and PRMT5, and its arginine residues are dimethylated.
  • PRMT1 is a component of RAP55A-induced granules, and PRMT1 knockdown impairs RAP55A localization to P-bodies.

Conclusions:

  • RAP55 proteins play a significant role in the assembly of cytoplasmic mRNP granules.
  • PRMT1 is required for the proper localization of RAP55A to P-bodies, highlighting a novel regulatory mechanism in mRNP granule dynamics.

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