1
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Marzo-Mas A, Barbier P, Breuzard G, Allegro D, Falomir E, Murga J, Carda M, Peyrot V, Marco JA. Interactions of long-chain homologues of colchicine with tubulin. Eur J Med Chem 2016; 126:526-535. [PMID: 27915168 DOI: 10.1016/j.ejmech.2016.11.049] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Revised: 11/21/2016] [Accepted: 11/22/2016] [Indexed: 01/30/2023]
Abstract
Several colchicine analogues in which the N-acetyl residue has been replaced by aliphatic, straight-chain acyl moieties, have been synthesized. These compounds show high cytotoxic activity at the nanomolar level against the tumoral cell lines HT-29, MCF-7 and A549. Some of them exhibit activities in the picomolar range against the HT-29 line and are thus two to three orders of magnitude more cytotoxic than colchicine. In this specific cell line, the activities were found to be closely related to the length of the acyl carbon chain, an increase in the latter giving rise to an increase in the cytotoxicity with a maximum in the range of 10-12 carbon atoms, followed by a decrease in activity with still longer chains. Some of the compounds inhibit microtubule assembly and induce the formation of abnormal polymers and present in most cases better apparent affinity constants than colchicine. In addition, at IC50 concentrations the analogues block the cell cycle of A549 cells in the G2/M phase. Molecular docking studies suggest that, while interactions of the colchicine analogues with the colchicine binding site at β-tubulin are still present, the increase in the acyl chain length leads to the progressive development of new interactions, not present in colchicine itself, with the neighboring α-tubulin subunit. Indeed, sufficiently long acyl chains span the intradimer interface and contact with a hydrophobic groove in α-tubulin. It is worth noting that some of the compounds show cytotoxicity at concentrations three orders of magnitude lower than colchicine. Their pharmacological use in cancer therapy could possibly be performed with lower dosages and be thus endowed with less acute toxicity problems than in the case of colchicine.
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Affiliation(s)
- Ana Marzo-Mas
- Depart. de Q. Inorgánica y Orgánica, Univ. Jaume I, E-12071 Castellón, Spain
| | - Pascale Barbier
- Aix-Marseille Université, Inserm, CRO2 UMR_S 911, Faculté de Pharmacie, 13385, Marseille, France
| | - Gilles Breuzard
- Aix-Marseille Université, Inserm, CRO2 UMR_S 911, Faculté de Pharmacie, 13385, Marseille, France
| | - Diane Allegro
- Aix-Marseille Université, Inserm, CRO2 UMR_S 911, Faculté de Pharmacie, 13385, Marseille, France
| | - Eva Falomir
- Depart. de Q. Inorgánica y Orgánica, Univ. Jaume I, E-12071 Castellón, Spain
| | - Juan Murga
- Depart. de Q. Inorgánica y Orgánica, Univ. Jaume I, E-12071 Castellón, Spain.
| | - Miguel Carda
- Depart. de Q. Inorgánica y Orgánica, Univ. Jaume I, E-12071 Castellón, Spain
| | - Vincent Peyrot
- Aix-Marseille Université, Inserm, CRO2 UMR_S 911, Faculté de Pharmacie, 13385, Marseille, France.
| | - J Alberto Marco
- Depart. de Q. Orgánica, Univ. de Valencia, E-46100 Burjassot, Valencia, Spain
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2
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Di Maïo IL, Barbier P, Allegro D, Brault C, Peyrot V. Quantitative analysis of tau-microtubule interaction using FRET. Int J Mol Sci 2014; 15:14697-714. [PMID: 25196605 PMCID: PMC4159876 DOI: 10.3390/ijms150814697] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Revised: 06/30/2014] [Accepted: 07/14/2014] [Indexed: 11/23/2022] Open
Abstract
The interaction between the microtubule associated protein, tau and the microtubules is investigated. A fluorescence resonance energy transfer (FRET) assay was used to determine the distance separating tau to the microtubule wall, as well as the binding parameters of the interaction. By using microtubules stabilized with Flutax-2 as donor and tau labeled with rhodamine as acceptor, a donor-to-acceptor distance of 54 ± 1 Å was found. A molecular model is proposed in which Flutax-2 is directly accessible to tau-rhodamine molecules for energy transfer. By titration, we calculated the stoichiometric dissociation constant to be equal to 1.0 ± 0.5 µM. The influence of the C-terminal tails of αβ-tubulin on the tau-microtubule interaction is presented once a procedure to form homogeneous solution of cleaved tubulin has been determined. The results indicate that the C-terminal tails of α- and β-tubulin by electrostatic effects and of recruitment seem to be involved in the binding mechanism of tau.
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Affiliation(s)
- Isabelle L Di Maïo
- Aix-Marseille Université, Inserm, CRO2 UMR_S 911, Faculté de Pharmacie, 27 Bd Jean Moulin, 13385 Marseille, France
| | - Pascale Barbier
- Aix-Marseille Université, Inserm, CRO2 UMR_S 911, Faculté de Pharmacie, 27 Bd Jean Moulin, 13385 Marseille, France.
| | - Diane Allegro
- Aix-Marseille Université, Inserm, CRO2 UMR_S 911, Faculté de Pharmacie, 27 Bd Jean Moulin, 13385 Marseille, France.
| | - Cédric Brault
- Aix-Marseille Université, Inserm, CRO2 UMR_S 911, Faculté de Pharmacie, 27 Bd Jean Moulin, 13385 Marseille, France.
| | - Vincent Peyrot
- Aix-Marseille Université, Inserm, CRO2 UMR_S 911, Faculté de Pharmacie, 27 Bd Jean Moulin, 13385 Marseille, France.
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3
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Canela MD, Pérez-Pérez MJ, Noppen S, Sáez-Calvo G, Díaz JF, Camarasa MJ, Liekens S, Priego EM. Novel colchicine-site binders with a cyclohexanedione scaffold identified through a ligand-based virtual screening approach. J Med Chem 2014; 57:3924-38. [PMID: 24773591 DOI: 10.1021/jm401939g] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Vascular disrupting agents (VDAs) constitute an innovative anticancer therapy that targets the tumor endothelium, leading to tumor necrosis. Our approach for the identification of new VDAs has relied on a ligand 3-D shape similarity virtual screening (VS) approach using the ROCS program as the VS tool and as query colchicine and TN-16, which both bind the α,β-tubulin dimer. One of the hits identified, using TN-16 as query, has been explored by the synthesis of its structural analogues, leading to 2-(1-((2-methoxyphenyl)amino)ethylidene)-5-phenylcyclohexane-1,3-dione (compound 16c) with an IC50 = 0.09 ± 0.01 μM in HMEC-1 and BAEC, being 100-fold more potent than the initial hit. Compound 16c caused cell cycle arrest in the G2/M phase and interacted with the colchicine-binding site in tubulin, as confirmed by a competition assay with N,N'-ethylenebis(iodoacetamide) and by fluorescence spectroscopy. Moreover, 16c destroyed an established endothelial tubular network at 1 μM and inhibited the migration and invasion of human breast carcinoma cells at 0.4 μM. In conclusion, our approach has led to a new chemotype of promising antiproliferative compounds with antimitotic and potential VDA properties.
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Affiliation(s)
- María-Dolores Canela
- Instituto de Química Médica (IQM-CSIC) , Juan de la Cierva 3, E-28006 Madrid, Spain
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4
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Abstract
Microtubules play an important role in a number of vital cell processes such as cell division, intracellular transport, and cell architecture. The highly dynamic structure of microtubules is tightly regulated by a number of stabilizing and destabilizing microtubule-associated proteins (MAPs), such as tau and stathmin. Because of their importance, tubulin-MAPs interactions have been extensively studied using various methods that provide researchers with complementary but sometimes contradictory thermodynamic data. Isothermal titration calorimetry (ITC) is the only direct thermodynamic method that enables a full thermodynamic characterization (stoichiometry, enthalpy, entropy of binding, and association constant) of the interaction after a single titration experiment. This method has been recently applied to study tubulin-MAPs interactions in order to bring new insights into molecular mechanisms of tubulin regulation. In this chapter, we review the technical specificity of this method and then focus on the use of ITC in the investigation of tubulin-MAPs binding. We describe technical issues which could arise during planning and carrying out the ITC experiments, in particular with fragile proteins such as tubulin. Using examples of stathmin and tau, we demonstrate how ITC can be used to gain major insights into tubulin-MAP interaction.
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5
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Martin-Galiano AJ, Oliva MA, Sanz L, Bhattacharyya A, Serna M, Yebenes H, Valpuesta JM, Andreu JM. Bacterial tubulin distinct loop sequences and primitive assembly properties support its origin from a eukaryotic tubulin ancestor. J Biol Chem 2011; 286:19789-803. [PMID: 21467045 DOI: 10.1074/jbc.m111.230094] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The structure of the unique bacterial tubulin BtubA/B from Prosthecobacter is very similar to eukaryotic αβ-tubulin but, strikingly, BtubA/B fold without eukaryotic chaperones. Our sequence comparisons indicate that BtubA and BtubB do not really correspond to either α- or β-tubulin but have mosaic sequences with intertwining features from both. Their nucleotide-binding loops are more conserved, and their more divergent sequences correspond to discrete surface zones of tubulin involved in microtubule assembly and binding to eukaryotic cytosolic chaperonin, which is absent from the Prosthecobacter dejongeii draft genome. BtubA/B cooperatively assembles over a wider range of conditions than αβ-tubulin, forming pairs of protofilaments that coalesce into bundles instead of microtubules, and it lacks the ability to differentially interact with divalent cations and bind typical tubulin drugs. Assembled BtubA/B contain close to one bound GTP and GDP. Both BtubA and BtubB subunits hydrolyze GTP, leading to disassembly. The mutant BtubA/B-S144G in the tubulin signature motif GGG(T/S)G(S/T)G has strongly inhibited GTPase, but BtubA-T147G/B does not, suggesting that BtubB is a more active GTPase, like β-tubulin. BtubA/B chimera bearing the β-tubulin loops M, H1-S2, and S9-S10 in BtubB fold, assemble, and have reduced GTPase activity. However, introduction of the α-tubulin loop S9-S10 with its unique eight-residue insertion impaired folding. From the sequence analyses, its primitive assembly features, and the properties of the chimeras, we propose that BtubA/B were acquired shortly after duplication of a spontaneously folding α- and β-tubulin ancestor, possibly by horizontal gene transfer from a primitive eukaryotic cell, followed by divergent evolution.
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Affiliation(s)
- Antonio J Martin-Galiano
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Madrid, Spain
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Barbier P, Dorléans A, Devred F, Sanz L, Allegro D, Alfonso C, Knossow M, Peyrot V, Andreu JM. Stathmin and interfacial microtubule inhibitors recognize a naturally curved conformation of tubulin dimers. J Biol Chem 2010; 285:31672-81. [PMID: 20675373 PMCID: PMC2951239 DOI: 10.1074/jbc.m110.141929] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Tubulin is able to switch between a straight microtubule-like structure and a curved structure in complex with the stathmin-like domain of the RB3 protein (T(2)RB3). GTP hydrolysis following microtubule assembly induces protofilament curvature and disassembly. The conformation of the labile tubulin heterodimers is unknown. One important question is whether free GDP-tubulin dimers are straightened by GTP binding or if GTP-tubulin is also curved and switches into a straight conformation upon assembly. We have obtained insight into the bending flexibility of tubulin by analyzing the interplay of tubulin-stathmin association with the binding of several small molecule inhibitors to the colchicine domain at the tubulin intradimer interface, combining structural and biochemical approaches. The crystal structures of T(2)RB3 complexes with the chiral R and S isomers of ethyl-5-amino-2-methyl-1,2-dihydro-3-phenylpyrido[3,4-b]pyrazin-7-yl-carbamate, show that their binding site overlaps with colchicine ring A and that both complexes have the same curvature as unliganded T(2)RB3. The binding of these ligands is incompatible with a straight tubulin structure in microtubules. Analytical ultracentrifugation and binding measurements show that tubulin-stathmin associations (T(2)RB3, T(2)Stath) and binding of ligands (R, S, TN-16, or the colchicine analogue MTC) are thermodynamically independent from one another, irrespective of tubulin being bound to GTP or GDP. The fact that the interfacial ligands bind equally well to tubulin dimers or stathmin complexes supports a bent conformation of the free tubulin dimers. It is tempting to speculate that stathmin evolved to recognize curved structures in unassembled and disassembling tubulin, thus regulating microtubule assembly.
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Affiliation(s)
- Pascale Barbier
- From INSERM UMR 911, Centre de Recherche en Oncologie Biologique et Oncopharmacologie, Aix-Marseille Université, Faculté de Pharmacie, 27 bd Jean Moulin, 13385 Marseille Cedex 05, France, , To whom correspondence may be addressed. E-mail:
| | - Audrey Dorléans
- the Laboratoire d'Enzymologie et Biochimie Structurales, CNRS UPR3082, 91198 Gif sur Yvette, France, and
| | - Francois Devred
- From INSERM UMR 911, Centre de Recherche en Oncologie Biologique et Oncopharmacologie, Aix-Marseille Université, Faculté de Pharmacie, 27 bd Jean Moulin, 13385 Marseille Cedex 05, France
| | - Laura Sanz
- the Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - Diane Allegro
- From INSERM UMR 911, Centre de Recherche en Oncologie Biologique et Oncopharmacologie, Aix-Marseille Université, Faculté de Pharmacie, 27 bd Jean Moulin, 13385 Marseille Cedex 05, France
| | - Carlos Alfonso
- the Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - Marcel Knossow
- the Laboratoire d'Enzymologie et Biochimie Structurales, CNRS UPR3082, 91198 Gif sur Yvette, France, and
| | - Vincent Peyrot
- From INSERM UMR 911, Centre de Recherche en Oncologie Biologique et Oncopharmacologie, Aix-Marseille Université, Faculté de Pharmacie, 27 bd Jean Moulin, 13385 Marseille Cedex 05, France
| | - Jose M. Andreu
- the Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, 28040 Madrid, Spain, To whom correspondence may be addressed. E-mail:
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7
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Devred F, Barbier P, Lafitte D, Landrieu I, Lippens G, Peyrot V. Microtubule and MAPs: thermodynamics of complex formation by AUC, ITC, fluorescence, and NMR. Methods Cell Biol 2010; 95:449-80. [PMID: 20466148 DOI: 10.1016/s0091-679x(10)95023-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Microtubules are implicated in many essential cellular processes such as architecture, cell division, and intracellular traffic, due to their dynamic instability. This dynamicity is tightly regulated by microtubule-associated proteins (MAPs), such as tau and stathmin. Despite extensive studies motivated by their central role in physiological functions and pathological role in neurodegenerative diseases and cancer, the precise mechanisms of tau and stathmin binding to tubulin and their consequences on microtubule stability are still not fully understood. One of the most crucial points missing is a quantitative thermodynamic description of their interaction with tubulin/microtubules and of the tubulin complexes formed upon these interactions. In this chapter, we will focus on the use of analytical ultracentrifugation, isothermal titration calorimetry, and nuclear magnetic resonance-three powerful and complementary techniques in the field of MAP-tubulin/microtubule interactions, in addition to the spectrometric techniques and co-sedimentation approach. We will present the limits of these techniques to study this particular interaction and precautions that need to be taken during MAPs preparation. Understanding the molecular mechanisms that govern MAPs action on microtubular network will not only shed new light on the role of this crucial family of protein in the biology of the cell, but also hopefully open new paths to increase the therapeutic efficiency of microtubule-targeting drugs in cancers therapies and neurodegeneratives diseases prevention.
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Affiliation(s)
- François Devred
- CRO2, U911 Inserm, Aix-Marseille Université, 27 Bd Jean Moulin, 13385 Marseille cedex 05, France
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8
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Bennett MJ, Chik JK, Slysz GW, Luchko T, Tuszynski J, Sackett DL, Schriemer DC. Structural mass spectrometry of the alpha beta-tubulin dimer supports a revised model of microtubule assembly. Biochemistry 2009; 48:4858-70. [PMID: 19388626 DOI: 10.1021/bi900200q] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The molecular basis of microtubule lattice instability derives from the hydrolysis of GTP to GDP in the lattice-bound state of alphabeta-tubulin. While this has been appreciated for many years, there is ongoing debate over the molecular basis of this instability and the possible role of altered nucleotide occupancy in the induction of a conformational change in tubulin. The debate has organized around seemingly contradictory models. The allosteric model invokes nucleotide-dependent states of curvature in the free tubulin dimer, such that hydrolysis leads to pronounced bending and thus disruption of the lattice. The more recent lattice model describes a predominant role for the lattice in straightening free dimers that are curved regardless of their nucleotide state. In this model, lattice-bound GTP-tubulin provides the necessary force to straighten an incoming dimer. Interestingly, there is evidence for both models. The enduring nature of this debate stems from a lack of high-resolution data on the free dimer. In this study, we have prepared alphabeta-tubulin samples at high dilution and characterized the nature of nucleotide-induced conformational stability using bottom-up hydrogen/deuterium exchange mass spectrometry (H/DX-MS) coupled with isothermal urea denaturation experiments. These experiments were accompanied by molecular dynamics simulations of the free dimer. We demonstrate an intermediate state unique to GDP-tubulin, suggestive of the curved colchicine-stabilized structure at the intradimer interface but show that intradimer flexibility is an important property of the free dimer regardless of nucleotide occupancy. Our results indicate that the assembly properties of the free dimer may be better described on the basis of this flexibility. A blended model of assembly emerges in which free-dimer allosteric effects retain importance, in an assembly process dominated by lattice-induced effects.
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Affiliation(s)
- Melissa J Bennett
- Department of Biochemistry and Molecular Biology, University of Calgary, 3330 Hospital Drive NW, Calgary, Alberta, Canada T2N 4N1
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9
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Amniai L, Barbier P, Sillen A, Wieruszeski JM, Peyrot V, Lippens G, Landrieu I. Alzheimer disease specific phosphoepitopes of Tau interfere with assembly of tubulin but not binding to microtubules. FASEB J 2008; 23:1146-52. [PMID: 19074508 DOI: 10.1096/fj.08-121590] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In Alzheimer disease (AD)-affected neurons, the Tau protein is found in an aggregated and hyperphosphorylated state. A common hypothesis is that Tau hyperphosphorylation causes its dissociation from the microtubular surface, with consequently a breakdown of the microtubules (MTs) and aggregation of the unbound Tau. We evaluated the effect of Tau phosphorylation on both tubulin assembly and MT binding. We show that the cyclin-dependent kinase 2/cyclin A3 kinase complex can generate the AT8 and AT180 AD-specific phospho-epitopes and use NMR spectroscopy to validate qualitatively and quantitatively the phospho content of our samples. The simultaneous presence of both epitopes disables the tubulin assembly capacity of Tau in conditions whereby Tau is the driving force for the assembly process but does not, however, inhibit MT assembly when the latter is driven by an increased tubulin concentration. When compared to the isolated MT binding repeats (K(d)=0.3 microM), the phospho-Tau retains a substantial affinity for preformed MTs (K(d)=11 nM), suggesting that the phosphorylated proline-rich region still participates in the binding event. Our results hence indicate that the sole phosphorylation at the AT8/AT180 epitopes, although leading to a functional defect for Tau, is not sufficient for its dissociation from the MT surface and subsequent aggregation as observed in AD.
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Affiliation(s)
- Laziza Amniai
- Université des Sciences et Technologies de Lille 1, Villeneuve d'Ascq, France
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10
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La Regina G, Edler MC, Brancale A, Kandil S, Coluccia A, Piscitelli F, Hamel E, De Martino G, Matesanz R, Díaz JF, Scovassi AI, Prosperi E, Lavecchia A, Novellino E, Artico M, Silvestri R. Arylthioindole Inhibitors of Tubulin Polymerization. 3. Biological Evaluation, Structure−Activity Relationships and Molecular Modeling Studies. J Med Chem 2007; 50:2865-74. [PMID: 17497841 DOI: 10.1021/jm061479u] [Citation(s) in RCA: 149] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The new arylthioindole (ATI) derivatives 10, 14-18, and 21-24, which bear a halogen atom or a small size ether group at position 5 of the indole moiety, were compared with the reference compounds colchicine and combretastatin A-4 for biological activity. Derivatives 10, 11, 16, and 21-24 inhibited MCF-7 cell growth with IC50 values <50 nM. A halogen atom (14-17) at position 5 caused a significant reduction in the free energy of binding of compound to tubulin, with a concomitant reduction in cytotoxicity. In contrast, methyl (21) and methoxy (22) substituents at position 5 caused an increase in cytotoxicity. Compound 16, the most potent antitubulin agent, led to a large increase (56%) in HeLa cells in the G2/M phase at 24 h, and at 48 h, 26% of the cells were hyperploid. Molecular modeling studies showed that, despite the absence of the ester moiety present in the previously examined analogues, most of the compounds bind in the colchicine site in the same orientation as the previously studied ATIs. Binding to beta-tubulin involved formation of a hydrogen bond between the indole and Thr179 and positioning of the trimethoxy phenyl group in a hydrophobic pocket near Cys241.
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Affiliation(s)
- Giuseppe La Regina
- Istituto Pasteur - Fondazione Cenci Bolognetti, Dipartimento di Studi Farmaceutici, Sapienza Università di Roma, Piazzale Aldo Moro 5, I-00185 Roma, Italy
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11
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Devred F, Barbier P, Douillard S, Monasterio O, Andreu JM, Peyrot V. Tau induces ring and microtubule formation from alphabeta-tubulin dimers under nonassembly conditions. Biochemistry 2004; 43:10520-31. [PMID: 15301550 DOI: 10.1021/bi0493160] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Tau is a neuronal microtubule-associated protein that plays a central role in many cellular processes, both physiological and pathological, such as axons stabilization and Alzheimer's disease. Despite extensive studies, very little is known about the detailed molecular basis of tau binding to microtubules. We used the four-repeat recombinant htau40 and tubulin dimers to show for the first time that tau is able to induce both microtubule and ring formation from 6S alphabeta tubulin in phosphate buffer without added magnesium (nonassembly conditions). The amount of microtubules or rings formed was protein concentration-, temperature-, and nucleotide-dependent. By means of biophysical approaches, we showed that tau binds to tubulin without global-folding change, detectable by circular dichroism. We also demonstrated that the tau-tubulin interaction follows a ligand-mediated elongation process, with two tau-binding site per tubulin dimer. Moreover, using a tubulin recombinant alpha-tubulin C-terminal fragment (404-451) and a beta-tubulin C-terminal fragment (394-445), we demonstrated the involvement of both of these tubulin regions in tau binding. From this model system, we gain new insight into the mechanisms by which tau binds to tubulin and induces microtubule formation.
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Affiliation(s)
- François Devred
- FRE 2737, ISPDCT, Faculté de Pharmacie, 27 Bd Jean Moulin, 13385 Marseille Cedex 5, France
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12
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Laurine E, Lafitte D, Grégoire C, Sérée E, Loret E, Douillard S, Michel B, Briand C, Verdier JM. Specific binding of dehydroepiandrosterone to the N terminus of the microtubule-associated protein MAP2. J Biol Chem 2003; 278:29979-86. [PMID: 12775713 DOI: 10.1074/jbc.m303242200] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The effect of neurosteroids is mediated through their membrane or nuclear receptors. However, no dehydroepiandrosterone (DHEA)-specific receptors have been evidenced so far in the brain. In this paper, we showed by isothermal titration calorimetry that the DHEA specifically binds to the dendritic brain microtubule-associated protein MAP2C with an association constant of 2.7 x 10(7) m-1 and at a molar ratio of 1:1. By partial tryptic digestions and mass spectrometry analysis, we found that the binding involved the N-terminal region of MAP2C. Interestingly, MAP2C displays homologies with 17 beta-hydroxysteroid dehydrogenase 1, an enzyme required for estrogen synthesis. Based on these sequence homologies and on the x-ray structure of the DHEA-binding pocket of 17 beta-hydroxysteroid dehydrogenase 1, we modeled the complex of DHEA with MAP2C. The binding of DHEA to MAP2C involved specific hydrogen bonds that orient the steroid into the pocket. This work suggests that DHEA can directly influence brain plasticity via MAP2C binding. It opens interesting ways for understanding the role of DHEA in the brain.
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MESH Headings
- Adjuvants, Immunologic/pharmacology
- Amino Acid Sequence
- Binding Sites
- Blotting, Western
- Brain/metabolism
- Calorimetry
- Cell Nucleus/metabolism
- Chromatography, High Pressure Liquid
- Chromatography, Ion Exchange
- Circular Dichroism
- Crystallography, X-Ray
- Cytoskeleton/metabolism
- DNA/metabolism
- Dehydroepiandrosterone/pharmacology
- Electrophoresis, Polyacrylamide Gel
- Escherichia coli/metabolism
- Humans
- Hydrogen Bonding
- Hydrogen-Ion Concentration
- Mass Spectrometry
- Microtubule-Associated Proteins/chemistry
- Microtubule-Associated Proteins/metabolism
- Models, Chemical
- Models, Molecular
- Molecular Sequence Data
- Peptides/chemistry
- Protein Binding
- Protein Isoforms
- Protein Structure, Secondary
- Protein Structure, Tertiary
- Sequence Homology, Amino Acid
- Trypsin/pharmacology
- Tubulin/chemistry
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Affiliation(s)
- Emmanuelle Laurine
- Ecole Pratique des Hautes Etudes, Université Montpellier II, Place Eugène Bataillon, CC94, 34095 Montpellier cedex 05, France
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13
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Devred F, Douillard S, Briand C, Peyrot V. First tau repeat domain binding to growing and taxol-stabilized microtubules, and serine 262 residue phosphorylation. FEBS Lett 2002; 523:247-51. [PMID: 12123840 DOI: 10.1016/s0014-5793(02)02999-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Tau phosphorylation plays a crucial role in microtubule stabilization and in Alzheimer's disease. To characterize the molecular mechanisms of tau binding on microtubules, we synthesized the peptide R1 (QTAPVPMPDLKNVKSKIGSTENLKHQPGGGKVQI), reproducing the first tau microtubule binding motif. We thermodynamically characterized the molecular mechanism of tubulin assembly with R1 in vitro, and measured, for the first time, the binding parameters of R1 on both growing and taxol-stabilized microtubules. In addition, we obtained similar binding parameters with R1 phosphorylated on Ser262. These data suggest that the consequences of Ser262 phosphorylation on tau binding to microtubules and on tubulin assembly are due to large intramolecular rearrangements of the tau protein.
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Affiliation(s)
- François Devred
- UMR CNRS 6032, Faculté de Pharmacie, 27 Boulevard Jean Moulin, 13385 Cedex 5, Marseille, France
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Tulub AA, Stefanov VE. Cisplatin stops tubulin assembly into microtubules. A new insight into the mechanism of antitumor activity of platinum complexes. Int J Biol Macromol 2001; 28:191-8. [PMID: 11251225 DOI: 10.1016/s0141-8130(00)00159-8] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Despite numerous studies considering DNA as a primary target of cisplatin attack, this work is the first to show the pure effect of cisplatin on the process of tubulin assembly/disassembly in vitro. When platinated, tubulin does not assemble into microtubules (direct electron microscopic studies). In place of them, highly stable and inert circled rings arise. Such tubulin aggregates are unable to participate in the process of chromosome separation during the mitosis, thus blocking cell division in living cells, which is a direct evidence of cisplatin antitumor activity. Cisplatin attack on tubulin causing blockage of tubulin assembly occurs via a two-step binding to GTP in the GTP center of tubulin ((195)Pt, (31)P NMR studies). The calculated binding rates are close to those reported in cisplatin-DNA interactions. The mechanism of cisplatin attack on tubulin is proposed.
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Affiliation(s)
- A A Tulub
- Department of Biochemistry, Faculty of Biology of St. Petersburg State University, Universitetskaya Nab. 7/9, 199034, St. Petersburg, Russia
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15
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Smyczynski C, Derancourt J, Chaussepied P. Regulation of ncd by the oligomeric state of tubulin. J Mol Biol 2000; 295:325-36. [PMID: 10623529 DOI: 10.1006/jmbi.1999.3356] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We have compared the interaction of ncd (non-claret disjunctional), a kinesin related protein, with microtubules and tubulin heterodimer. Ultracentrifugation experiments revealed that the ncd motor domain, residues 335-700 (ncd335), does not induce tubulin polymerization but stabilizes pre-formed microtubules with a maximum effect at a 1:1 ncd335:tubulin ratio. Ncd335 binding to tubulin or microtubules was estimated by following the change in fluorescence polarization of an exogenous dye attached to Cys670 of ncd335. Ncd335 binding to tubulin (containing GTP or GDP-bound) is characterized by a 2:1 stoichiometry, a higher affinity and an increased sensitivity towards salt, ADP, ATP and AMPPNP, as compared with ncd335 binding to microtubules. Maximum ATPases were 0.06-0.08 sec(-1) and 1.8-2.0 sec(-1) for the ncd335-tubulin and ncd335-microtubules complexes, respectively. Only the polymerized complex is fully functional, suggesting the presence of additional contacts between adjacent protofilaments. Moreover, the data reveal that the oligomeric state of microtubules is a potent regulator for the activity of kinesin related proteins.
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Affiliation(s)
- C Smyczynski
- CRBM du CNRS, IFR 24, Montpellier C¿edex 05, 34293, France
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Peyrot V, Barbier P, Sarrazin M, Briand C, Andreu JM. Chirality and Spectroscopic Changes Induced by the Recognition of Ethyl 5-Amino-2-methyl-1,2-dihydro-3-phenylpyrido[3,4-b]pyrazin-7-yl Carbamate Analogs by Tubulin. Photochem Photobiol 1999. [DOI: 10.1111/j.1751-1097.1999.tb08274.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Abstract
The structure of tubulin has recently been determined by electron crystallography, paving the way for a clearer understanding of the unique properties of tubulin that allow its varied functions within the cell. Some of the ongoing work on tubulin can be interpreted in terms of its structure, which can serve to guide future studies.
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Affiliation(s)
- K H Downing
- Donner Laboratory Life Science Division Lawrence Berkeley National Laboratory Molecular and Cell Biology University of California Berkely CA 94720 USA.
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