Tcp20, a subunit of the eukaryotic TRiC chaperonin from humans and yeast.
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 that 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.
Department of Medicine, University of Rochester, School of Medicine and Dentistry, New York 14642.
W Z
WZ
Li
P
P
Lin
J
J
Frydman
T R
TR
Boal
T S
TS
Cardillo
L M
LM
Richard
D
D
Toth
M A
MA
Lichtman
F U
FU
Hartl
F
F
Sherman
D000595:Amino Acid Sequence; D001483:Base Sequence; D056404:Chaperonin Containing TCP-1; D018833:Chaperonins; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D017931:DNA Primers; D018076:DNA, Complementary / Q000032:analysis; D004926:Escherichia coli / Q000378:metabolism; D015723:Gene Library; D005800:Genes, Fungal; D006801:Humans; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D014176:Protein Biosynthesis; D011506:Proteins / Q000235:genetics / Q000302:isolation & purification; D012333:RNA, Messenger / Q000096:biosynthesis; D015183:Restriction Mapping; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D017386:Sequence Homology, Amino Acid
C088425:CCT6 protein, S cerevisiae; D017931:DNA Primers; D018076:DNA, Complementary; D046911:Macromolecular Substances; D011506:Proteins; D012333:RNA, Messenger; D029701:Saccharomyces cerevisiae Proteins; C533304:TCP1 protein, human; D056404:Chaperonin Containing TCP-1; D018833:Chaperonins