Chaperonin-mediated protein folding

Reviewed: Cowan, NJ, 2009-01-21 16:47:24 Edited: Matthews, L, 2009-02-21 04:38:35 Authored: Matthews, L, 2008-12-01 04:46:41 The eukaryotic chaperonin TCP-1 ring complex (TRiC/ CCT) plays an essential role in the folding of a subset of proteins prominent among which are the actins and tubulins (reviewed in Altschuler and Willison, 2008). CCT/TRiC is an example of a type II chaperonin, defined (in contrast to type I) as functioning in the absence of a cochaperonin. TriC/CCT is a multisubunit toroidal complex that forms a cylinder containing two back-to-back stacked rings enclosing a cavity where substrate folding occurs in an ATP dependent process (reviewed in Altschuler and Willison, 2008 ). CCT/TriC contains eight paralogous subunits that are conserved throughout eukaryotic organisms (Leroux and Hartl 2000; Archibald et al. 2001; Valpuesta et al. 2002). CCT-mediated folding of non-native substrate protein involves capture through hydrophobic contacts with multiple chaperonin subunits followed by transfer of the protein into the central ring cavity where it folds. Although folding is initiated within this central cavity, only 5%–20% of proteins that are released have partitioned to the native state. The remaining portion is then recaptured by other chaperonin molecules (Cowan and Lewis 2001). This cycling process may be repeated multiple times before a target protein partitions to the native state. In the cell, binding to CCT occurs via presentation of target protein bound to upstream chaperones. During translation, the emerging polypeptide chain may be transferred from the ribosome to CCT via the chaperone Prefoldin (Vainberg et al., 1998) or the Hsp70 chaperone machinery (Melville et al., 2003). While the majority of CCT substrates ultimately partition to the native state as soluble, monomeric proteins, alpha and beta tubulin are unusual in that they require additional cofactors that are required to assemble the tubulin heterodimer (Cowan and Lewis 2001).

http://purl.obolibrary.org/obo/HINO_0016757

Reviewed: Cowan, NJ, 2009-01-21 16:47:24

Edited: Matthews, L, 2009-02-21 04:38:35

Authored: Matthews, L, 2008-12-01 04:46:41

The eukaryotic chaperonin TCP-1 ring complex (TRiC/ CCT) plays an essential role in the folding of a subset of proteins prominent among which are the actins and tubulins (reviewed in Altschuler and Willison, 2008). CCT/TRiC is an example of a type II chaperonin, defined (in contrast to type I) as functioning in the absence of a cochaperonin. TriC/CCT is a multisubunit toroidal complex that forms a cylinder containing two back-to-back stacked rings enclosing a cavity where substrate folding occurs in an ATP dependent process (reviewed in Altschuler and Willison, 2008 ). CCT/TriC contains eight paralogous subunits that are conserved throughout eukaryotic organisms (Leroux and Hartl 2000; Archibald et al. 2001; Valpuesta et al. 2002). CCT-mediated folding of non-native substrate protein involves capture through hydrophobic contacts with multiple chaperonin subunits followed by transfer of the protein into the central ring cavity where it folds. Although folding is initiated within this central cavity, only 5%–20% of proteins that are released have partitioned to the native state. The remaining portion is then recaptured by other chaperonin molecules (Cowan and Lewis 2001). This cycling process may be repeated multiple times before a target protein partitions to the native state. In the cell, binding to CCT occurs via presentation of target protein bound to upstream chaperones. During translation, the emerging polypeptide chain may be transferred from the ribosome to CCT via the chaperone Prefoldin (Vainberg et al., 1998) or the Hsp70 chaperone machinery (Melville et al., 2003). While the majority of CCT substrates ultimately partition to the native state as soluble, monomeric proteins, alpha and beta tubulin are unusual in that they require additional cofactors that are required to assemble the tubulin heterodimer (Cowan and Lewis 2001).

Pubmed11580265

Pubmed15519848

Reactome, http://www.reactome.org

Pubmed12697815

Pubmed9630229

Pubmed10753735

Pubmed11868281

Pubmed18708324

Pubmed12354605

Chaperonin-mediated protein folding

http://purl.obolibrary.org/obo/NCBITaxon_9606

HINO:0016757

Chaperonin-mediated protein folding

Reactome Database ID Release 43390466

ReactomeREACT_17004

GENE ONTOLOGYGO:0006457

http://purl.obolibrary.org/obo/INO_0000021

http://purl.obolibrary.org/obo/HINO_0016756

http://purl.obolibrary.org/obo/HINO_0016750