P-Body Purification Reveals the Condensation of Repressed mRNA Regulons

Mol Cell. 2017 Oct 5;68(1):144-157.e5. doi: 10.1016/j.molcel.2017.09.003. Epub 2017 Sep 28.


Within cells, soluble RNPs can switch states to coassemble and condense into liquid or solid bodies. Although these phase transitions have been reconstituted in vitro, for endogenous bodies the diversity of the components, the specificity of the interaction networks, and the function of the coassemblies remain to be characterized. Here, by developing a fluorescence-activated particle sorting (FAPS) method to purify cytosolic processing bodies (P-bodies) from human epithelial cells, we identified hundreds of proteins and thousands of mRNAs that structure a dense network of interactions, separating P-body from non-P-body RNPs. mRNAs segregating into P-bodies are translationally repressed, but not decayed, and this repression explains part of the poor genome-wide correlation between RNA and protein abundance. P-bodies condense thousands of mRNAs that strikingly encode regulatory processes. Thus, we uncovered how P-bodies, by condensing and segregating repressed mRNAs, provide a physical substrate for the coordinated regulation of posttranscriptional mRNA regulons.

Keywords: P-bodies; RNP condensation; RNP granules; decay; gene expression regulation; phase separation; phase transition; regulon; stress granules; translation repression.

MeSH terms

  • Cell Fractionation
  • Cytoplasm / metabolism
  • Cytoplasmic Granules / chemistry
  • Cytoplasmic Granules / metabolism
  • Gene Expression Regulation*
  • Gene Ontology
  • HEK293 Cells
  • HeLa Cells
  • Humans
  • Molecular Sequence Annotation
  • Phase Transition
  • Protein Biosynthesis
  • Proteome / genetics*
  • Proteome / metabolism
  • RNA Stability
  • RNA, Messenger / genetics*
  • RNA, Messenger / metabolism
  • Regulon*
  • Ribonucleoproteins / genetics*
  • Ribonucleoproteins / metabolism


  • Proteome
  • RNA, Messenger
  • Ribonucleoproteins