Macromolecular complexes as depots for releasable regulatory proteins

Trends Biochem Sci. 2007 Apr;32(4):158-64. doi: 10.1016/j.tibs.2007.02.003. Epub 2007 Feb 23.


Multi-component, macromolecular complexes perform essential cellular functions that require spatial or temporal coordination of activities. Complexes also facilitate co-regulation of protein amounts and cellular localization of individual components. We propose a novel function of multi-component complexes as depots for regulatory proteins that, upon release, acquire new auxiliary functions. We further propose that component release is inducible and context-dependent. We describe two cases in which multi-component assemblies - the ribosome and tRNA multi-synthetase complex--function as depots. Both complexes have crucial roles in supporting protein synthesis but they also release regulatory proteins for inflammation-responsive, transcript-specific translational control. Recent evidence indicates that other macromolecular assemblies might be sources for proteins with auxiliary functions, and the depot mechanism might be widespread in nature.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Animals
  • Humans
  • Models, Biological
  • Models, Molecular
  • Multiprotein Complexes / chemistry
  • Multiprotein Complexes / metabolism*
  • Protein Binding
  • Protein Biosynthesis
  • Proteins / chemistry
  • Proteins / metabolism*
  • Ribosomes / metabolism


  • Multiprotein Complexes
  • Proteins