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Lafanechère L. The microtubule cytoskeleton: An old validated target for novel therapeutic drugs. Front Pharmacol 2022; 13:969183. [PMID: 36188585 PMCID: PMC9521402 DOI: 10.3389/fphar.2022.969183] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Accepted: 08/30/2022] [Indexed: 12/02/2022] Open
Abstract
Compounds targeting microtubules are widely used in cancer therapy with a proven efficacy. However, because they also target non-cancerous cells, their administration leads to numerous adverse effects. With the advancement of knowledge on the structure of tubulin, the regulation of microtubule dynamics and their deregulation in pathological processes, new therapeutic strategies are emerging, both for the treatment of cancer and for other diseases, such as neuronal or even heart diseases and parasite infections. In addition, a better understanding of the mechanism of action of well-known drugs such as colchicine or certain kinase inhibitors contributes to the development of these new therapeutic approaches. Nowadays, chemists and biologists are working jointly to select drugs which target the microtubule cytoskeleton and have improved properties. On the basis of a few examples this review attempts to depict the panorama of these recent advances.
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Laisne MC, Michallet S, Lafanechère L. Characterization of Microtubule Destabilizing Drugs: A Quantitative Cell-Based Assay That Bridges the Gap between Tubulin Based- and Cytotoxicity Assays. Cancers (Basel) 2021; 13:cancers13205226. [PMID: 34680374 PMCID: PMC8533752 DOI: 10.3390/cancers13205226] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 10/13/2021] [Accepted: 10/15/2021] [Indexed: 12/14/2022] Open
Abstract
Simple Summary The characterization of new microtubule depolymerizing agents relies mainly on purified tubulin assays in vitro and on cytotoxicity tests. However, the relationship between the in vitro effects of drugs and their effect on cell viability may not be direct. Here, we have systematically compared the effect of four reference drugs on tubulin polymerization in vitro and in cells, using a recently-developed quantitative assay of the cellular microtubule content. By comparing these results with cell viability assays, we found that this new cellular microtubule content test better predicts cellular drug toxicity than the in vitro tubulin polymerization assay. This test can thus be easily implemented in the process of discovery and characterization of novel microtubule poisons. Abstract (1) Background: Microtubule depolymerizing agents (MDAs) are commonly used for cancer treatment. However, the therapeutic use of such microtubule inhibitors is limited by their toxicity and the emergence of resistance. Thus, there is still a sustained effort to develop new MDAs. During the characterization of such agents, mainly through in vitro analyses using purified tubulin and cytotoxicity assays, quantitative comparisons are mandatory. The relationship between the effect of the drugs on purified tubulin and on cell viability are not always direct. (2) Methods: We have recently developed a cell-based assay that quantifies the cellular microtubule content. In this study, we have conducted a systematic comparative analysis of the effect of four well-characterized MDAs on the kinetics of in vitro tubulin assembly, on the cellular microtubule content (using our recently developed assay) and on cell viability. (3) Conclusions: These assays gave complementary results. Additionally, we found that the drugs’ effect on in vitro tubulin polymerization is not completely predictive of their relative cytotoxicity. Their effect on the cellular microtubule content, however, is closely related to their effect on cell viability. In conclusion, the assay we have recently developed can bridge the gap between in vitro tubulin assays and cell viability assays.
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Aillaud C, Bosc C, Saoudi Y, Denarier E, Peris L, Sago L, Taulet N, Cieren A, Tort O, Magiera MM, Janke C, Redeker V, Andrieux A, Moutin MJ. Evidence for new C-terminally truncated variants of α- and β-tubulins. Mol Biol Cell 2016; 27:640-53. [PMID: 26739754 PMCID: PMC4750924 DOI: 10.1091/mbc.e15-03-0137] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Accepted: 12/22/2015] [Indexed: 11/11/2022] Open
Abstract
New C-terminally truncated α- and β-tubulin variants, both ending with an –EEEG sequence, are identified in vivo: αΔ3-tubulin, which has a specific neuronal distribution pattern (distinct from that of αΔ2-tubulin) and seems to be related to dynamic microtubules, and βΔ4-tubulin, corresponding to β2A/B-tubulin modified by truncation of four C-terminal residues, which is ubiquitously present in cells and tissues. Cellular α-tubulin can bear various carboxy-terminal sequences: full-length tubulin arising from gene neosynthesis is tyrosinated, and two truncated variants, corresponding to detyrosinated and Δ2 α‑tubulin, result from the sequential cleavage of one or two C-terminal residues, respectively. Here, by using a novel antibody named 3EG that is highly specific to the –EEEG C-terminal sequence, we demonstrate the occurrence in neuronal tissues of a new αΔ3‑tubulin variant corresponding to α1A/B‑tubulin deleted of its last three residues (EEY). αΔ3‑tubulin has a specific distribution pattern: its quantity in the brain is similar to that of αΔ2-tubulin around birth but is much lower in adult tissue. This truncated α1A/B-tubulin variant can be generated from αΔ2-tubulin by the deglutamylases CCP1, CCP4, CCP5, and CCP6 but not by CCP2 and CCP3. Moreover, using 3EG antibody, we identify a C‑terminally truncated β-tubulin form with the same –EEEG C-terminal sequence. Using mass spectrometry, we demonstrate that β2A/B-tubulin is modified by truncation of the four C-terminal residues (EDEA). We show that this newly identified βΔ4-tubulin is ubiquitously present in cells and tissues and that its level is constant throughout the cell cycle. These new C-terminally truncated α- and β-tubulin variants, both ending with –EEEG sequence, are expected to regulate microtubule physiology. Of interest, the αΔ3-tubulin seems to be related to dynamic microtubules, resembling tyrosinated-tubulin rather than the other truncated variants, and may have critical function(s) in neuronal development.
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Affiliation(s)
- Chrystelle Aillaud
- Université Grenoble Alpes, Grenoble Institut des Neurosciences, GIN, F-38000 Grenoble, France Inserm, U1216, F-38000 Grenoble, France
| | - Christophe Bosc
- Université Grenoble Alpes, Grenoble Institut des Neurosciences, GIN, F-38000 Grenoble, France Inserm, U1216, F-38000 Grenoble, France
| | - Yasmina Saoudi
- Université Grenoble Alpes, Grenoble Institut des Neurosciences, GIN, F-38000 Grenoble, France Inserm, U1216, F-38000 Grenoble, France
| | - Eric Denarier
- Université Grenoble Alpes, Grenoble Institut des Neurosciences, GIN, F-38000 Grenoble, France Inserm, U1216, F-38000 Grenoble, France CEA, BIG-GPC, F-38000 Grenoble, France
| | - Leticia Peris
- Université Grenoble Alpes, Grenoble Institut des Neurosciences, GIN, F-38000 Grenoble, France Inserm, U1216, F-38000 Grenoble, France
| | - Laila Sago
- Service d'Identification et de Caractérisation des Protéines par Spectrométrie de masse, CNRS, 91198 Gif-sur-Yvette, France
| | - Nicolas Taulet
- Centre de Recherche de Biochimie Macromoléculaire, CNRS, 34293 Montpellier, France
| | - Adeline Cieren
- Université Grenoble Alpes, Grenoble Institut des Neurosciences, GIN, F-38000 Grenoble, France Inserm, U1216, F-38000 Grenoble, France
| | - Olivia Tort
- Institut de Biotecnologia i de Biomedicina, Department of Biochemistry and Molecular Biology, Universitat Autònoma de Barcelona, 08193 Bellaterra (Barcelona), Spain Institut Curie, 91405 Orsay, France Paris Sciences et Lettres Research University, 75005 Paris, France Centre National de la Recherche Scientifique, UMR3348, 91405 Orsay, France
| | - Maria M Magiera
- Institut Curie, 91405 Orsay, France Paris Sciences et Lettres Research University, 75005 Paris, France Centre National de la Recherche Scientifique, UMR3348, 91405 Orsay, France
| | - Carsten Janke
- Institut Curie, 91405 Orsay, France Paris Sciences et Lettres Research University, 75005 Paris, France Centre National de la Recherche Scientifique, UMR3348, 91405 Orsay, France
| | - Virginie Redeker
- Service d'Identification et de Caractérisation des Protéines par Spectrométrie de masse, CNRS, 91198 Gif-sur-Yvette, France Paris-Saclay Institute of Neuroscience, CNRS, 91198 Gif-sur-Yvette Cedex, France
| | - Annie Andrieux
- Université Grenoble Alpes, Grenoble Institut des Neurosciences, GIN, F-38000 Grenoble, France Inserm, U1216, F-38000 Grenoble, France
| | - Marie-Jo Moutin
- Université Grenoble Alpes, Grenoble Institut des Neurosciences, GIN, F-38000 Grenoble, France Inserm, U1216, F-38000 Grenoble, France
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Caplow M, Fee L. Dissociation of the tubulin dimer is extremely slow, thermodynamically very unfavorable, and reversible in the absence of an energy source. Mol Biol Cell 2002; 13:2120-31. [PMID: 12058074 PMCID: PMC117629 DOI: 10.1091/mbc.e01-10-0089] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The finding that exchange of tubulin subunits between tubulin dimers (alpha-beta + alpha'beta' <--> alpha'beta + alphabeta') does not occur in the absence of protein cofactors and GTP hydrolysis conflicts with the assumption that pure tubulin dimer and monomer are in rapid equilibrium. This assumption underlies the many physical chemical measurements of the K(d) for dimer dissociation. To resolve this discrepancy we used surface plasmon resonance to determine the rate constant for dimer dissociation. The half-time for dissociation was approximately 9.6 h with tubulin-GTP, 2.4 h with tubulin-GDP, and 1.3 h in the absence of nucleotide. A Kd equal to 10(-11) M was calculated from the measured rate for dissociation and an estimated rate for association. Dimer dissociation was found to be reversible, and dimer formation does not require GTP hydrolysis or folding information from protein cofactors, because 0.2 microM tubulin-GDP incubated for 20 h was eluted as dimer when analyzed by size exclusion chromatography. Because 20 h corresponds to eight half-times for dissociation, only monomer would be present if dissociation were an irreversible reaction and if dimer formation required GTP or protein cofactors. Additional evidence for a 10(-11) M K(d) was obtained from gel exclusion chromatography studies of 0.02-2 nM tubulin-GDP. The slow dissociation of the tubulin dimer suggests that protein tubulin cofactors function to catalyze dimer dissociation, rather than dimer assembly. Assuming N-site-GTP dissociation is from monomer, our results agree with the 16-h half-time for N-site GTP in vitro and 33 h half-life for tubulin N-site-GTP in CHO cells.
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Affiliation(s)
- Michael Caplow
- Department of Biochemistry, University of North Carolina, Chapel Hill, North Carolina 27599-7260, USA.
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Fleury D, Grenningloh G, Lafanechère L, Antonsson B, Job D, Cohen-Addad C. Preliminary crystallographic study of a complex formed between the alpha/beta-tubulin heterodimer and the neuronal growth-associated protein SCG10. J Struct Biol 2000; 131:156-8. [PMID: 11042086 DOI: 10.1006/jsbi.2000.4283] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Crystals of a complex formed between the alpha/beta-tubulin heterodimer and SCG10, a neuron-specific growth-associated protein, have been obtained by the hanging drop method. They belong to the space group P2(1)2(1)2(1), with unit cell parameters a = 56 A, b = 353 A, c = 466 A and four molecular complexes in the asymmetric unit. A complete X-ray diffraction data set to 6.1 A resolution has been collected using synchrotron radiation. This represents a challenging opportunity to study at a molecular level the structure-function relationships between a microtubule-destabilizing protein, SCG10, and tubulin.
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Affiliation(s)
- D Fleury
- Institut de Biologie Structurale Jean-Pierre Ebel, CEA/CNRS/University Joseph Fourier, 41 rue Jules Horowitz, Grenoble Cedex 1, 38027, France
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Tian G, Bhamidipati A, Cowan NJ, Lewis SA. Tubulin folding cofactors as GTPase-activating proteins. GTP hydrolysis and the assembly of the alpha/beta-tubulin heterodimer. J Biol Chem 1999; 274:24054-8. [PMID: 10446175 DOI: 10.1074/jbc.274.34.24054] [Citation(s) in RCA: 87] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In vivo, many proteins must interact with molecular chaperones to attain their native conformation. In the case of tubulin, newly synthesized alpha- and beta-subunits are partially folded by cytosolic chaperonin, a double-toroidal ATPase with homologs in all kingdoms of life and in most cellular compartments. alpha- and beta-tubulin folding intermediates are then brought together by tubulin-specific chaperone proteins (named cofactors A-E) in a cofactor-containing supercomplex with GTPase activity. Here we show that tubulin subunit exchange can only occur by passage through this supercomplex, thus defining it as a dimer-making machine. We also show that hydrolysis of GTP by beta-tubulin in the supercomplex acts as a switch for the release of native tubulin heterodimer. In this folding reaction and in the related reaction of tubulin-folding cofactors with native tubulin, the cofactors behave as GTPase-activating proteins, stimulating the GTP-binding protein beta-tubulin to hydrolyze its GTP.
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Affiliation(s)
- G Tian
- Department of Biochemistry, New York University Medical Center, New York, New York 10016, USA
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