Review: Cellular substrates of the eukaryotic chaperonin TRiC/CCT

The TCP-1 ring complex (TRiC; also called CCT, for chaperonin containing TC P-1) is a large (similar to 900 kDa) multisubunit complex that mediates pro tein folding in the eukaryotic cytosol. The physiological substrate spectru m of TRiC is still poorly defined. Genetic and biochemical data show that i t is required for the folding of the cytoskeletal proteins actin and tubuli n. Recent years have witnessed a steady stream of reports that describe oth er proteins that require TRiC for proper folding. Furthermore, analysis of the transit of newly synthesized proteins through TRiC in intact cells sugg ests that the chaperonin contributes to the folding of a distinct subset of cellular proteins. Here we review the current understanding of a role for TRiC in the folding of newly synthesized polypeptides, with a focus on some of the individual proteins that require TRiC. (C) 2001 Aademic Press.