Subunits of the eukaryotic cytosolic chaperonin CCT do not always behave as components of a uniform hetero-oligomeric particle

Roobol, Anne; Carden, Martin J.

doi:10.1016/s0171-9335(99)80004-1

Cited by 50 publications

(53 citation statements)

References 45 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These results demonstrate that PhLP interacts with at least four subunits of CCT in human cell extracts and in CHO cells under immunoprecipitation conditions that are not expected to disrupt the CCT oligomer (34). Thus, it appears that PhLP is binding to the holo-CCT complex.…”

Section: Resultsmentioning

confidence: 76%

Regulatory interaction of phosducin-like protein with the cytosolic chaperonin complex

McLaughlin

Thulin

Hart

et al. 2002

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

Phosducin and phosducin-like protein (PhLP) bind G protein ␤␥ subunits and regulate their activity. This report describes a previously uncharacterized binding partner unique to PhLP that was discovered by coimmunoprecipitation coupled with mass spectrometric identification. Chaperonin containing tailless complex polypeptide 1 (CCT), a cytosolic chaperone responsible for the folding of many cellular proteins, binds PhLP with a stoichiometry of one PhLP per CCT complex. Unlike protein-folding substrates of CCT, which interact only in their nonnative conformations, PhLP binds in its native state. Native PhLP competes directly for binding of protein substrates of CCT and thereby inhibits CCT activity. Overexpression of PhLP inhibited the ability of CCT to fold newly synthesized ␤-actin by 80%. These results suggest that the interaction between PhLP and CCT may be a means to regulate CCT-dependent protein folding or alternatively, to control the availability of PhLP to modulate G protein signaling.

show abstract

Section: Resultsmentioning

confidence: 76%

Regulatory interaction of phosducin-like protein with the cytosolic chaperonin complex

McLaughlin

Thulin

Hart

et al. 2002

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

show abstract

“…In addition, TCP-1 was also detected in pIII, but not pII. In both the cases, CCT subunits were also found in lower molecular mass fractions (120 -60 kDa), suggesting disassembly of the CCT complex (36,37).…”

Section: Association Of Newly Synthesized Hmm With a Molecularmentioning

confidence: 89%

“…2), we detected disassembly of the CCT complex. Nucleotidedependent disassembly of CCT has been reported and may represent a novel feature of this class of chaperonin (36,37). Assembly dynamics of this type could facilitate the binding of highly asymmetric molecules like myosin by the CCT complex, thus, obviating the conceptual constraint imposed by models requiring entry of asymmetric proteins into a narrow cavity.…”

Section: Fig 2 Gel Filtration Chromatography Of Nascent Hmm a Mg 2ϩmentioning

confidence: 99%

Myosin II Folding Is Mediated by a Molecular Chaperonin

Srikakulam¹,

Winkelmann²

1999

Journal of Biological Chemistry

100

View full text Add to dashboard Cite

The folding pathway of the heavy meromyosin subfragment (HMM) of a skeletal muscle myosin has been investigated by in vitro synthesis of the myosin heavy and light chains in a coupled transcription and translation assay. Analysis of the nascent translation products for folding intermediates has identified a major intermediate that contains all three myosin subunits in a complex with the eukaryotic cytosolic chaperonin. Partially folded HMM is released from this complex in an ATP-dependent manner. However, biochemical and functional assays reveal incomplete folding of the myosin motor domain. Dimerization of myosin heavy chains and association of heavy and light chains are accomplished early in the folding pathway. To test for other factors necessary for the complete folding of myosin, a cytoplasmic extract was prepared from myotubes produced by a mouse myogenic cell line. This extract dramatically enhanced the folding of HMM, suggesting a role for muscle-specific factors in the folding pathway. We conclude that the molecular assembly of myosin is mediated by the eukaryotic cytosolic chaperonin with folding of the motor domain as the slow step in the pathway.

show abstract

“…This does not rule out that other CCT subunit arrangements of TRiC may exist, especially in different tissues and at different developmental stages. Previous research has shown that TRiC complexes containing specific subunits may have different roles (Roobol et al 1995) and even that the CCT subunits may have functions in the cell independent of the TRiC complex (Roobol and Carden 1999).…”

Section: Introductionmentioning

confidence: 99%

Human TRiC complex purified from HeLa cells contains all eight CCT subunits and is active in vitro

Knee

Sergeeva

King

2013

Cell Stress and Chaperones

View full text Add to dashboard Cite

Archaeal and eukaryotic cytosols contain group II chaperonins, which have a double-barrel structure and fold proteins inside a cavity in an ATP-dependent manner. The most complex of the chaperonins, the eukaryotic TCP-1 ring complex (TRiC), has eight different subunits, chaperone containing TCP-1 (CCT1-8), that are arranged so that there is one of each subunit per ring. Aspects of the structure and function of the bovine and yeast TRiC have been characterized, but studies of human TRiC have been limited. We have isolated and purified endogenous human TRiC from HeLa suspension cells. This purified human TRiC contained all eight CCT subunits organized into double-barrel rings, consistent with what has been found for bovine and yeast TRiC. The purified human TRiC is active as demonstrated by the luciferase refolding assay. As a more stringent test, the ability of human TRiC to suppress the aggregation of human γD-crystallin was examined. In addition to suppressing offpathway aggregation, TRiC was able to assist the refolding of the crystallin molecules, an activity not found with the lens chaperone, α-crystallin. Additionally, we show that human TRiC from HeLa cell lysate is associated with the heat shock protein 70 and heat shock protein 90 chaperones. Purification of human endogenous TRiC from HeLa cells will enable further characterization of this key chaperonin, required for the reproduction of all human cells.

show abstract

Subunits of the eukaryotic cytosolic chaperonin CCT do not always behave as components of a uniform hetero-oligomeric particle

Cited by 50 publications

References 45 publications

Regulatory interaction of phosducin-like protein with the cytosolic chaperonin complex

Regulatory interaction of phosducin-like protein with the cytosolic chaperonin complex

Myosin II Folding Is Mediated by a Molecular Chaperonin

Human TRiC complex purified from HeLa cells contains all eight CCT subunits and is active in vitro

Contact Info

Product

Resources

About