Function in protein folding of TRiC, a cytosolic ring complex containing TCP-1 and structurally related subunits

EMBO J. 1992 Dec;11(13):4767-78. doi: 10.1002/j.1460-2075.1992.tb05582.x.


T-complex polypeptide 1 (TCP-1) was analyzed as a potential chaperonin (GroEL/Hsp60) equivalent of the eukaryotic cytosol. We found TCP-1 to be part of a hetero-oligomeric 970 kDa complex containing several structurally related subunits of 52-65 kDa. These members of a new protein family are assembled into a TCP-1 ring complex (TRiC) which resembles the GroEL double ring. The main function of TRiC appears to be in chaperoning monomeric protein folding: TRiC binds unfolded polypeptides, thereby preventing their aggregation, and mediates the ATP-dependent renaturation of unfolded firefly luciferase and tubulin. At least in vitro, TRiC appears to function independently of a small co-chaperonin protein such as GroES. Folding of luciferase is mediated by TRiC but not by GroEL/ES. This suggests that the range of substrate proteins interacting productively with TRiC may differ from that of GroEL. We propose that TRiC mediates the folding of cytosolic proteins by a mechanism distinct from that of the chaperonins in specific aspects.

Publication types

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

MeSH terms

  • Adenosine Triphosphatases / metabolism
  • Adenosine Triphosphate / metabolism
  • Amino Acid Sequence
  • Animals
  • Bacterial Proteins / chemistry
  • Cattle
  • Chaperonin 60
  • Chaperonins
  • Coleoptera / enzymology
  • Electrophoresis, Polyacrylamide Gel
  • Enzyme Activation
  • Heat-Shock Proteins / chemistry
  • Intracellular Signaling Peptides and Proteins*
  • Luciferases / chemistry
  • Luciferases / metabolism
  • Male
  • Microscopy, Electron, Scanning Transmission
  • Microtubule-Associated Proteins*
  • Molecular Sequence Data
  • Nuclear Proteins / chemistry*
  • Nuclear Proteins / metabolism
  • Protein Binding
  • Protein Folding*
  • Proteins / chemistry
  • Sequence Homology, Amino Acid
  • Tubulin / chemistry
  • Ubiquitin-Protein Ligases
  • t-Complex Genome Region


  • Bacterial Proteins
  • Chaperonin 60
  • Heat-Shock Proteins
  • Intracellular Signaling Peptides and Proteins
  • Microtubule-Associated Proteins
  • Nuclear Proteins
  • Proteins
  • Tubulin
  • Adenosine Triphosphate
  • Luciferases
  • PPP1R11 protein, human
  • Ubiquitin-Protein Ligases
  • Adenosine Triphosphatases
  • Chaperonins

Associated data

  • GENBANK/M12899