Our hosting provider will be performing UPS maintenance on Tuesday, Oct 25, 2016 between 8 AM and 5 PM PDT. SciCrunch searching services will be down during this time.

Preparing your results

Our searching services are busy right now. Your search will reload in five seconds.

Forgot Password

If you have forgotten your password you can enter your email here and get a temporary password sent to your email.

Protein-protein interactions between human exosome components support the assembly of RNase PH-type subunits into a six-membered PNPase-like ring.


The exosome is a complex of 3'-->5' exoribonucleases, which functions in a variety of cellular processes, all requiring the processing or degradation of RNA. Here we present a model for the assembly of the six human RNase PH-like exosome subunits into a hexameric ring structure. In part, this structure is on the basis of the evolutionarily related bacterial degradosome, the core of which consists of three copies of the PNPase protein, each containing two RNase PH domains. In our model three additional exosome subunits, which contain S1 RNA-binding domains, are positioned on the outer surface of this ring. Evidence for this model was obtained by the identification of protein-protein interactions between individual exosome subunits in a mammalian two-hybrid system. In addition, the results of co-immunoprecipitation assays indicate that at least two copies of hRrp4p and hRrp41p are associated with a single exosome, suggesting that at least two of these ring structures are present in this complex. Finally, the identification of a human gene encoding the putative human counterpart of the bacterial PNPase protein is described, which suggests that the exosome is not the eukaryotic equivalent of the bacterial degradosome, although they do share similar functional activities.

Pubmed ID: 12419256


  • Raijmakers R
  • Egberts WV
  • van Venrooij WJ
  • Pruijn GJ


Journal of molecular biology

Publication Data

November 1, 2002

Associated Grants


Mesh Terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Blotting, Western
  • COS Cells
  • Cell Line
  • Cloning, Molecular
  • Computational Biology
  • Exocytosis
  • Exoribonucleases
  • Humans
  • Molecular Sequence Data
  • Phylogeny
  • Polyribonucleotide Nucleotidyltransferase
  • Precipitin Tests
  • Protein Binding
  • Protein Structure, Quaternary
  • Protein Subunits
  • Saccharomyces cerevisiae
  • Sequence Homology, Amino Acid
  • Transfection
  • Two-Hybrid System Techniques