Selective localization of PCBP2 to cytoplasmic processing bodies

Biochim Biophys Acta. 2009 May;1793(5):878-87. doi: 10.1016/j.bbamcr.2009.02.002. Epub 2009 Feb 20.


Processing bodies (P-bodies) are cytoplasmic domains that have been implicated in critical steps of the regulation of gene expression, including mRNA decay and post-transcriptional gene silencing. Previously, we reported that PCBP2 (Poly-(rC) Binding Protein 2), a facilitator of IRES-mediated translation, is a novel P-body component. Interestingly, PCBP2 is recruited to only a subset of Dcp1a-positive P-bodies, which may reflect functional diversity among these structures. In this study, we examined the selective P-body localization of PCBP2 in detail. Co-localization studies between Dcp1a and PCBP2 revealed that PCBP2 is present in approximately 40% of P-bodies. While PCBP2 was more likely to reside in larger P-bodies, P-body size did not seem to be the sole determinant, and puromycin-induced enlargement of P-bodies only modestly increased the percentage of PCBP2-positive P-bodies. Photobleaching experiments demonstrated that the accumulation of PCBP2 to specific P-bodies is a dynamic process, which does not involve the protein's transcription-dependent nucleo-cytoplasmic shuttling activity. Finally, we found that PCBP1, a close relative of PCBP2, localizes to P-bodies in a similar manner to PCBP2. Taken together, these results establish the compositional diversity among P-bodies, and that PCBP2, probably in complex with other mRNP factors, may dynamically recognize such differences and accumulate to specific P-bodies.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Argonaute Proteins
  • Cytoplasm / metabolism*
  • Cytoplasmic Vesicles / metabolism*
  • Cytoplasmic Vesicles / ultrastructure
  • DNA-Binding Proteins
  • Endoribonucleases / metabolism
  • Eukaryotic Initiation Factors / genetics
  • Eukaryotic Initiation Factors / metabolism
  • Fluorescence Recovery After Photobleaching
  • Fluorescent Dyes / metabolism
  • HeLa Cells
  • Heterogeneous-Nuclear Ribonucleoproteins / genetics
  • Heterogeneous-Nuclear Ribonucleoproteins / metabolism
  • Humans
  • Protein Synthesis Inhibitors / metabolism
  • Puromycin / metabolism
  • RNA-Binding Proteins / genetics
  • RNA-Binding Proteins / metabolism*
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Trans-Activators / metabolism


  • AGO1 protein, human
  • Argonaute Proteins
  • DNA-Binding Proteins
  • Eukaryotic Initiation Factors
  • Fluorescent Dyes
  • Heterogeneous-Nuclear Ribonucleoproteins
  • PCBP1 protein, human
  • PCBP2 protein, human
  • Protein Synthesis Inhibitors
  • RNA-Binding Proteins
  • Recombinant Fusion Proteins
  • Trans-Activators
  • Puromycin
  • Endoribonucleases
  • DCP1A protein, human