Chaperonins are multisubunit, cylinder-shaped molecular chaperones involved in folding newly synthesized polypeptides.

Chaperonins are key components of the cellular chaperone machinery. These large, cylindrical complexes contain a central cavity that binds to unfolded polypeptides and sequesters them from the cellular environment. Substrate folding then occurs in this central cavity in an ATP-dependent manner.

The eukaryotic chaperonin TCP-1 ring complex (TRiC, also called CCT) is indispensable for cell survival because the folding of an essential subset of cytosolic proteins requires TRiC, and this function cannot be substituted by other chaperones. This specificity indicates that TRiC has evolved structural and mechanistic features that distinguish it from other chaperones.

Pathology

 BBS6 mutations in Bardet-Bield syndrome (BBS)

References

 Spiess C, Meyer AS, Reissmann S, Frydman J. Mechanism of the eukaryotic chaperonin: protein folding in the chamber of secrets. Trends Cell Biol. 2004 Nov;14(11):598-604. PMID: #15519848#

 Rutherford SL. Between genotype and phenotype : protein chaperones and evolvability. Nat Rev Genet. 2003 Apr ;4(4):263-74. PMID : #12671657#

 Slavotinek AM, Biesecker LG. Unfolding the role of chaperones and chaperonins in human disease. Trends Genet. 2001 Sep ;17(9):528-35. PMID : #11525836#