Two families of chaperonin: Physiology and mechanism

Arthur L. Horwich, Wayne A. Fenton, Eli Chapman, George W. Farr

Research output: Contribution to journalReview articlepeer-review

350 Scopus citations


Chaperonins are large ring assemblies that assist protein folding to the native state by binding nonnative proteins in their central cavities and then, upon binding ATP, release the substrate protein into a now-encapsulated cavity to fold productively. Two families of such components have been identified: type I in mitochondria, chloroplasts, and the bacterial cytosol, which rely on a detachable "lid" structure for encapsulation, and type II in archaea and the eukaryotic cytosol, which contain a built-in protrusion structure. We discuss here a number of issues under current study. What is the range of substrates acted on by the two classes of chaperonin, in particular by GroEL in the bacterial cytoplasm and CCT in the eukaryotic cytosol, and are all these substrates subject to encapsulation? What are the determinants for substrate binding by the type II chaperonins? And is the encapsulated chaperonin cavity a passive container that prevents aggregation, or could it be playing an active role in polypeptide folding?

Original languageEnglish (US)
Pages (from-to)115-145
Number of pages31
JournalAnnual Review of Cell and Developmental Biology
StatePublished - 2007


  • Aggregation
  • CCT
  • GroEL
  • GroES
  • Protein folding
  • Thermosome

ASJC Scopus subject areas

  • Developmental Biology
  • Cell Biology


Dive into the research topics of 'Two families of chaperonin: Physiology and mechanism'. Together they form a unique fingerprint.

Cite this