ATP-independent diffusion of double-stranded RNA binding proteins

Hye Ran Koh, Mary Anne Kidwell, Kaushik Ragunathan, Jennifer A. Doudna, Sua Myong

Research output: Contribution to journalArticlepeer-review


The proteins harboring double-stranded RNA binding domains (dsRBDs) play diverse functional roles such as RNA localization, splicing, editing, export, and translation, yet mechanistic basis and functional significance of dsRBDs remain unclear. To unravel this enigma, we investigated transactivation response RNA binding protein (TRBP) consisting of three dsRBDs, which functions in HIV replication, protein kinase R(PKR)-mediated immune response, and RNA silencing. Here we report an ATP-independent diffusion activity of TRBP exclusively on dsRNA in a length-dependent manner. The first two dsRBDs of TRBP are essential for diffusion, whereas the third dsRBD is dispensable. Two homologs of TRBP, PKR activator and R3D1-L, displayed the same diffusion, implying a universality of the diffusion activity among this protein family. Furthermore, a Dicer-TRBP complex on dsRNA exhibited dynamic diffusion, which was correlated with Dicer's catalytic activity. These results implicate the dsRNA-specific diffusion activity of TRBP that contributes to enhancing siRNA and miRNA processing by Dicer.

Original languageEnglish (US)
Pages (from-to)151-156
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number1
StatePublished - Jan 2 2013


  • RNA interference
  • Single molecule FRET

ASJC Scopus subject areas

  • General

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