Identification of six Tcp-1-related genes encoding divergent subunits of the TCP-1-containing chaperonin

  title={Identification of six Tcp-1-related genes encoding divergent subunits of the TCP-1-containing chaperonin},
  author={Hiroshi Kubota and Gillian M. Hynes and Alexander Carne and Alan Ashworth and Keith R. Willison},
  journal={Current Biology},
The chaperonin containing t-complex polypeptide 1 (TCP-1). Multisubunit machinery assisting in protein folding and assembly in the eukaryotic cytosol.
Observations, in conjunction with biochemical and genetic analysis, suggest that CCT functions as a very complex machinery for protein folding in the eukaryotic cell and that its chaperone activity may be essential for the folding and assembly of various newly synthesized polypeptides.
Cloning, expression and mapping of the full-length cDNA of human CCTβ subunit
A novel full-length cDNA of 1935 bp contains a 1605 bp open reading frame (ORF) encoding 535 amino acids (aa) and the deduced protein of the cDNA is highly homologous to the CCTβ subunit ofsaccharomyces cerevisiae,schizosac charomyces pombe, caenorhabditis elegans and mouse, etc.
Structures and co-regulated expression of the genes encoding mouse cytosolic chaperonin CCT subunits.
It is shown, by Western and Northern blot analyses, that CCT expression levels vary widely among different tissues but the expression patterns are very similar among the eight subunit species.
Subunit characterization of the Caenorhabditis elegans chaperonin containing TCP-1 and expression pattern of the gene encoding CCT-1.
Surprisingly, the co-purified HSP60 chaperonin present in the C. elegans CCT preparation has the greatest binding activity for denatured actin, an observation which is consistent with the participation of CCT in actin and tubulin folding.
The Chaperonin Containing TCP-1 (CCT). Displays a Single-Ring Mediated Disassembly and Reassembly Cycle
The chaperonin-containing TCP-1 (CCT) assists in the folding of actins and tubulins in eukaryotic cells. CCT is composed of 8 subunit species encoded by separate genes. CCT purifies as a single
Elucidation of the subunit orientation in CCT (chaperonin containing TCP1) from the subunit composition of CCT micro‐complexes
The series of subunit–subunit association patterns determined from CCT micro‐complexes has provided information to infer, from the 5040 (7!factorial) combinatorial possibilities, one probable subunit orientation within the toroidal ring.
Individual Subunits of the Eukaryotic Cytosolic Chaperonin Mediate Interactions with Binding Sites Located on Subdomains of β-Actin*
A model is proposed in which actin interacts with several CCT subunits during its CCT-mediated folding cycle, which is consistent with the recent cryo-electron microscopy three-dimensional structure of apo-CCT-α-actin, in which α-Actin is bound by the apical domains of specific C CT subunits.
Evolution of the chaperonin families (HSP60, HSP 10 and TCP‐1) of proteins and the origin of eukaryotic cells
Phylogenetic analysis based on global alignments of Hsp60 and Hsp10 sequences presented here provide some evidence regarding the evolution of mitochondria from a member of the α‐subdivision of Gram‐negative bacteria and chloroplasts from cyanobacterial species, respectively.


Sequence and structural homology between a mouse T-complex protein TCP-1 and the 'chaperonin' family of bacterial (GroEL, 60-65 kDa heat shock antigen) and eukaryotic proteins.
  • R. Gupta
  • Biology
    Biochemistry international
  • 1990
The sequence data suggest that in contrast to the endosymbiotic origin of mitochondrial and chloroplast chaperonins, the cytoplasmic TCP-1 may have directly descended from the common universal ancestor via eukaryotic lineage.
Function in protein folding of TRiC, a cytosolic ring complex containing TCP‐1 and structurally related subunits.
It is proposed that TRiC mediates the folding of cytosolic proteins by a mechanism distinct from that of the chaperonins in specific aspects.
Primary structure and function of a second essential member of the heterooligomeric TCP1 chaperonin complex of yeast, TCP1 beta.
It is concluded that TCP1 beta supplies an essential function that partially overlaps with that of TCP1 alpha in acting as a molecular chaperone in tubulin and spindle biogenesis.
T-complex polypeptide-1 is a subunit of a heteromeric particle in the eukaryotic cytosol
In the native state, murine and human TCP1 is distributed throughout the cytosol as an 800K–950K hetero-oligomeric particle in association with four to six unidentified proteins and two Hsp70 heat-shock proteins.
A molecular chaperone from a thermophilic archaebacterium is related to the eukaryotic protein t-complex polypeptide-1
It is suggested that TF55 in archaebacteria and TCP1 in the eukaryotic cytosol are members of a new class of molecular chaperones.
TCP1 complex is a molecular chaperone in tubulin biogenesis
It is concluded that TCP1 functions as a cytosolic chaperone in the biogenesis of tubulin, and newly translated tubulin subunits entered a 900K complex in a protease-sensitive conformation.
ATCPl-related molecular chaperone from plants refolds phytochrome to its photoreversible form
It is proposed that this protein is the cytosolic chaperone involved in phytochrome biogenesis in plant cells, and can stimulate refolding of denatured phy tochrome to a photoactive form in the presence of Mg–ATP.
An ATPase domain common to prokaryotic cell cycle proteins, sugar kinases, actin, and hsp70 heat shock proteins.
A common evolutionary origin for all of the proteins in this class is proposed, and a pattern of amino acid properties required at each position is defined, which significantly matches sugar kinases, such as fuco-, glucono-, xylulo-, ribulo-, and glycerokinase.
Similarity of the three-dimensional structures of actin and the ATPase fragment of a 70-kDa heat shock cognate protein.
A local sequence "fingerprint," which may be diagnostic of the adenine nucleotide beta-phosphate-binding pocket, has been derived and identifies members of the glycerol kinase family as candidates likely to have a similar structure in their nucleotide-binding domains.