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Ghozlan H, Cox A, Nierenberg D, King S, Khaled AR. The TRiCky Business of Protein Folding in Health and Disease. Front Cell Dev Biol 2022; 10:906530. [PMID: 35602608 PMCID: PMC9117761 DOI: 10.3389/fcell.2022.906530] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 04/20/2022] [Indexed: 01/03/2023] Open
Abstract
Maintenance of the cellular proteome or proteostasis is an essential process that when deregulated leads to diseases like neurological disorders and cancer. Central to proteostasis are the molecular chaperones that fold proteins into functional 3-dimensional (3D) shapes and prevent protein aggregation. Chaperonins, a family of chaperones found in all lineages of organisms, are efficient machines that fold proteins within central cavities. The eukaryotic Chaperonin Containing TCP1 (CCT), also known as Tailless complex polypeptide 1 (TCP-1) Ring Complex (TRiC), is a multi-subunit molecular complex that folds the obligate substrates, actin, and tubulin. But more than folding cytoskeletal proteins, CCT differs from most chaperones in its ability to fold proteins larger than its central folding chamber and in a sequential manner that enables it to tackle proteins with complex topologies or very large proteins and complexes. Unique features of CCT include an asymmetry of charges and ATP affinities across the eight subunits that form the hetero-oligomeric complex. Variable substrate binding capacities endow CCT with a plasticity that developed as the chaperonin evolved with eukaryotes and acquired functional capacity in the densely packed intracellular environment. Given the decades of discovery on the structure and function of CCT, much remains unknown such as the scope of its interactome. New findings on the role of CCT in disease, and potential for diagnostic and therapeutic uses, heighten the need to better understand the function of this essential molecular chaperone. Clues as to how CCT causes cancer or neurological disorders lie in the early studies of the chaperonin that form a foundational knowledgebase. In this review, we span the decades of CCT discoveries to provide critical context to the continued research on the diverse capacities in health and disease of this essential protein-folding complex.
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Affiliation(s)
- Heba Ghozlan
- Division of Cancer Research, Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL, United States
- Department of Physiology and Biochemistry, Jordan University of Science and Technology, Irbid, Jordan
| | - Amanda Cox
- Division of Cancer Research, Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL, United States
| | - Daniel Nierenberg
- Division of Cancer Research, Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL, United States
| | - Stephen King
- Division of Neuroscience, Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL, United States
| | - Annette R. Khaled
- Division of Cancer Research, Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL, United States
- *Correspondence: Annette R. Khaled,
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Marcia M, Langer JD, Parcej D, Vogel V, Peng G, Michel H. Characterizing a monotopic membrane enzyme. Biochemical, enzymatic and crystallization studies on Aquifex aeolicus sulfide:quinone oxidoreductase. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2010; 1798:2114-23. [DOI: 10.1016/j.bbamem.2010.07.033] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2010] [Revised: 07/28/2010] [Accepted: 07/29/2010] [Indexed: 10/19/2022]
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Abstract
Brucella abortus is a facultative, intracellular, pathogenic bacterium that replicates within macrophages and resists macrophage microbicidal mechanisms. To study gene expression and to elucidate the defense mechanisms used by B. abortus to resist destruction within macrophages, protein synthesis by B. abortus was examined by pulse-labeling techniques during intracellular growth within J774A.1, a macrophage-like cell line. Prominent changes observed include increased synthesis of Brucella proteins with estimated molecular masses of 62, 28, 24, and 17 kDa. The 62-kDa protein was identified by immunoprecipitation analysis as Hsp62, a GroEL homolog. A protein of 60 kDa was expressed during acid shock and may represent a modified form of Hsp62. The 28- and 17-kDa proteins have not been observed under any in vitro stress condition and presumably represent macrophage-specific induction. The 24-kDa protein comigrates with an unidentified protein induced by acid shock, designated Asp24. Expression of Asp24 is optimal at pH values below 4.0 and within the first 3 h following a shift from pH 7.3 to 3.8. This corresponds directly with a period of optimal bacterial survival at a reduced pH and suggests an active role for this protein in resistance to such environments. The identification of these gene products and the mechanisms controlling their expression is an important step in understanding the resistance of Brucella spp. to intracellular destruction within macrophages.
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Affiliation(s)
- J Lin
- Department of Veterinary Pathobiology, College of Veterinary Medicine, Texas A&M University, College Station
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Marco S, Carrascosa JL, Valpuesta JM. Reversible interaction of beta-actin along the channel of the TCP-1 cytoplasmic chaperonin. Biophys J 1994; 67:364-8. [PMID: 7919008 PMCID: PMC1225367 DOI: 10.1016/s0006-3495(94)80489-8] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The cytoplasm of eukaryotes contains a heteromeric toroidal chaperonin assembled from the t-complex TCP-1 and several other related polypeptides. The structure of the TCP-1 cytoplasmic chaperonin and that of the binary complex formed between this chaperonin and unfolded beta-actin have been studied using electron microscopy and image processing techniques. Two-dimensional averaging of front views reveals a circular stain-excluding mass surrounding a central stain-penetrating region in which the stain is excluded upon actin binding. Sections of a three-dimensional reconstruction of the chaperonin show that the inner core is an empty channel that becomes filled upon binary complex formation with unfolded beta-actin. Upon incubation with Mg-ATP, the beta-actin:chaperonin complex discharges the actin such that the chaperonin central cavity reappears. Side views from different forms of TCP-1 reveals that upon Mg-ATP binding, the cytoplasmic chaperonin undergoes a structural rearrangement that is confirmed using a new classification method.
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Affiliation(s)
- S Marco
- Centro Nacional de Biotecnología, C.S.I.C., Campus Universidad Autónoma, Madrid, Spain
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