Tcp20, a subunit of the eukaryotic TRiC chaperonin from humans and yeast

• Published in: The Journal of biological chemistry 1994-07, Vol.269 (28), p.18616-18622
• Main Authors: Li, W.Z, Lin, P, Frydman, J, Boal, T.R, Cardillo, T.S, Richard, L.M, Toth, D, Lichtman, M.A, Hartl, F.U, Shermans, F
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Analytical, structural and metabolic biochemistry; Base Sequence; Binding and carrier proteins; Biological and medical sciences; cDNA; Chaperonin Containing TCP-1; Chaperonins; Chromosome Mapping; Cloning, Molecular; DNA Primers; DNA, Complementary - analysis; Escherichia coli - metabolism; Fundamental and applied biological sciences. Psychology; GENE; Gene Library; GENERO HUMANO; GENES; Genes, Fungal; GENRE HUMAIN; heat shock proteins; Humans; Macromolecular Substances; man; Molecular Sequence Data; nucleotide sequence; Polymerase Chain Reaction; prediction; Protein Biosynthesis; PROTEINAS AGLUTINANTES; PROTEINE DE LIAISON; Proteins; Proteins - genetics; Proteins - isolation & purification; Restriction Mapping; RNA, Messenger - biosynthesis; SACCHAROMYCES CEREVISIAE; Saccharomyces cerevisiae - genetics; Saccharomyces cerevisiae - metabolism; Saccharomyces cerevisiae Proteins; SECUENCIA NUCLEICA; Sequence Homology, Amino Acid; SEQUENCE NUCLEIQUE; TCP20 gene
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1016/S0021-9258(17)32354-2

Members of the Hsp60 chaperonin family, such as Escherichia coli GroEL/S and the eukaryotic cytosolic chaperonin complex, TRiC (TCP ring complex), are double toroid complexes capable of assisting the folding of proteins in vitro in an ATP-dependent fashion. TRIC differs from the GroEL chaperonin in t1 at it has a hetero rather than homo-oligomeric subunit composition and lacks a GroES-like regulatory cofactor. We have established greater than 57% identity between a protein encoded by the TCP20 gene from a human cDNA library and the newly identified protein encoded by the TCP20 gene located on the right arm of chromosome IV of the yeast Saccharomyces cerevisiae. These Tcp20 proteins showed approximately 30% identity to Tcp1, a known subunit of TRIC. Gel filtration, followed by Western analysis of purified bovine testis TRiC with a Tcp20-specific antibody, indicated that Tcp20 is a subunit of the hetero-oligomeric TRiC. Gene disruption experiments showed that TCP20, like TCP1, is an essential gene in yeast, consistent with the view that TRiC is required for folding of key proteins. The amino acid sequence similarities and the derived evolutionary relationships established that the human and yeast Tcp20 proteins represent members of a new family of subunits of TRiC chaperonins