A cytoplasmic chaperonin that catalyzes beta-actin folding

Cell. 1992 Jun 12;69(6):1043-50. doi: 10.1016/0092-8674(92)90622-j.


We have isolated a cytoplasmic chaperonin based on its ability to catalyze the folding of denatured beta-actin. The cytoplasmic chaperonin is organized as a multisubunit toroid and requires Mg2+ and ATP for activity. The folding reaction proceeds via the rapid ATP-independent formation of a binary complex, followed by a slower ATP-dependent release of the native product. Electron microscopic observations reveal a striking structural change that occurs upon addition of Mg2+ and ATP. The eukaryotic cytoplasm thus contains a chaperonin that is functionally analagous to its prokaryotic, mitochondrial, and chloroplastic counterparts.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Actins / ultrastructure*
  • Adenosine Triphosphate / metabolism
  • Animals
  • Chaperonins
  • Chickens
  • Cytoplasm / metabolism
  • Electrophoresis, Gel, Two-Dimensional
  • In Vitro Techniques
  • Protein Conformation*
  • Proteins / immunology
  • Proteins / metabolism*
  • Recombinant Proteins


  • Actins
  • Proteins
  • Recombinant Proteins
  • Adenosine Triphosphate
  • Chaperonins