The exosome and the proteasome: nano-compartments for degradation.

Abstract

Exosomes and proteasomes are macromolecular complexes that posttranscriptionally regulate gene expression by degrading mRNAs and proteins, respectively. Although the two complexes act on different substrates and are composed of different subunits, they share a similar barrel-like architecture that appears to have evolved to restrict substrate access and prevent indiscriminate degradation.