Actin Interacts with CCT via Discrete Binding Sites: A Binding transition-release Model for CCT-Mediated Actin Folding

Neirynck, Katrien; Waterschoot, Davy; Vandekerckhove, Joël; Ampè, Christophe; Rommelaere, Heidi

doi:10.1016/j.jmb.2005.10.051

Cited by 43 publications

(55 citation statements)

References 43 publications

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“…There is experimental evidence that strong intermolecular interactions play a role in the course of CCT-actin folding (Hynes & Willison 2000;McCormack et al 2001b;Neirynck et al 2006;Pappenberger et al 2006). Immunoprecipitation of CCT pre-loaded with unfolded actin has identified specific CCT subunits involved in mediating a specific interaction with actin and a complementary b-actin peptide array analysis has mapped the corresponding sites on actin (Hynes & Willison 2000).…”

Section: Strong Actin-cct Interaction Modelmentioning

confidence: 99%

“…Free-energy-based CCT-actin models G. M. Altschuler and K. R. Willison 1403 could predominantly be to provide energy for interdomain conformational rearrangements rather than folding specific domains. In simulation experiments on actin unfolding, it has been reported that opening up the interdomain cleft introduces steric clashes between the large and small domains and that these can be alleviated by the removal of the C-terminus (residues 332-375 in human b-actin; Neirynck et al 2006). Furthermore, certain mutations in the C-terminus and in regions interacting with the C-terminus in the native structure have been found to inhibit actin release from CCT.…”

Section: Preserved Folding Energy and F-actin Dynamicsmentioning

confidence: 99%

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Development of free-energy-based models for chaperonin containing TCP-1 mediated folding of actin

Altschuler

Willison

2008

J. R. Soc. Interface.

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A free-energy-based approach is used to describe the mechanism through which chaperonincontaining TCP-1 (CCT) folds the filament-forming cytoskeletal protein actin, which is one of its primary substrates. The experimental observations on the actin folding and unfolding pathways are collated and then re-examined from this perspective, allowing us to determine the position of the CCT intervention on the actin free-energy folding landscape. The essential role for CCT in actin folding is to provide a free-energy contribution from its ATP cycle, which drives actin to fold from a stable, trapped intermediate I 3 , to a less stable but now productive folding intermediate I 2 . We develop two hypothetical mechanisms for actin folding founded upon concepts established for the bacterial type I chaperonin GroEL and extend them to the much more complex CCT system of eukaryotes. A new model is presented in which CCT facilitates free-energy transfer through direct coupling of the nucleotide hydrolysis cycle to the phases of actin substrate maturation.

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Section: Strong Actin-cct Interaction Modelmentioning

confidence: 99%

Section: Preserved Folding Energy and F-actin Dynamicsmentioning

confidence: 99%

Development of free-energy-based models for chaperonin containing TCP-1 mediated folding of actin

Altschuler

Willison

2008

J. R. Soc. Interface.

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“…Another simultaneous study showed that TRiC was capable of binding and folding proteins to their native states (Frydman et al 1992). Structures of TRiC with tubulin and actin have since been resolved and showed that TRiC recognizes and binds these essential protein substrates that first led to its discovery (Hynes and Willison 2000;Llorca et al 2001;Muñoz et al 2011;Neirynck et al 2006). …”

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

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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.

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“…Through a variety of structural, functional, and cell biology methods, interactions between TRiC and its main substrates, actin and tubulin, have been well characterized (13)(14)(15)(16)(17)(18)(19). However, TRiC binding is not limited to actin and tubulin; TRiC binds 9 -15% of newly synthesized proteins in [ 35 S]methionine pulse-labeled baby hamster kidney cells (4).…”

mentioning

confidence: 99%

Human CCT4 and CCT5 Chaperonin Subunits Expressed in Escherichia coli Form Biologically Active Homo-oligomers

Sergeeva

Chen

Haase-Pettingell

et al. 2013

Journal of Biological Chemistry

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Background:The subunit-specific roles of the CCT subunits in the chaperonin, TRiC, have not been elucidated. Results: When expressed in E. coli, CCT4 and CCT5 form TRiC-like homo-oligomeric rings. Conclusion: TRiC does not require all eight CCT subunits to form functional rings. Significance: The unexpected formation of homo-oligomeric CCT rings provides clues into the assembly of TRiC as a complex.

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Actin Interacts with CCT via Discrete Binding Sites: A Binding transition-release Model for CCT-Mediated Actin Folding

Cited by 43 publications

References 43 publications

Development of free-energy-based models for chaperonin containing TCP-1 mediated folding of actin

Development of free-energy-based models for chaperonin containing TCP-1 mediated folding of actin

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

Human CCT4 and CCT5 Chaperonin Subunits Expressed in Escherichia coli Form Biologically Active Homo-oligomers

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