1
|
Zhou J, Wang A, Song Y, Liu N, Wang J, Li Y, Liang X, Li G, Chu H, Wang HW. Structural insights into the mechanism of GTP initiation of microtubule assembly. Nat Commun 2023; 14:5980. [PMID: 37749104 PMCID: PMC10519996 DOI: 10.1038/s41467-023-41615-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Accepted: 09/08/2023] [Indexed: 09/27/2023] Open
Abstract
In eukaryotes, the dynamic assembly of microtubules (MT) plays an important role in numerous cellular processes. The underlying mechanism of GTP triggering MT assembly is still unknown. Here, we present cryo-EM structures of tubulin heterodimer at their GTP- and GDP-bound states, intermediate assembly states of GTP-tubulin, and final assembly stages of MT. Both GTP- and GDP-tubulin heterodimers adopt similar curved conformations with subtle flexibility differences. In head-to-tail oligomers of tubulin heterodimers, the inter-dimer interface of GDP-tubulin exhibits greater flexibility, particularly in tangential bending. Cryo-EM of the intermediate assembly states reveals two types of tubulin lateral contacts, "Tube-bond" and "MT-bond". Further, molecular dynamics (MD) simulations show that GTP triggers lateral contact formation in MT assembly in multiple sequential steps, gradually straightening the curved tubulin heterodimers. Therefore, we propose a flexible model of GTP-initiated MT assembly, including the formation of longitudinal and lateral contacts, to explain the nucleation and assembly of MT.
Collapse
Affiliation(s)
- Ju Zhou
- State Key Laboratory of Membrane Biology, Tsinghua University, Beijing, 100084, China
- Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084, China
- Beijing Frontier Research Center for Biological Structures, Tsinghua University, Beijing, 100084, China
- University of California Berkeley, Berkeley, CA, USA
| | - Anhui Wang
- Laboratory of Molecular Modeling and Design, State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Science, 457 Zhongshan Road, Dalian, 116023, China
| | - Yinlong Song
- Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084, China
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, Utrecht, Netherlands
| | - Nan Liu
- State Key Laboratory of Membrane Biology, Tsinghua University, Beijing, 100084, China
- Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084, China
- Beijing Frontier Research Center for Biological Structures, Tsinghua University, Beijing, 100084, China
| | - Jia Wang
- State Key Laboratory of Membrane Biology, Tsinghua University, Beijing, 100084, China
- Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084, China
- Beijing Frontier Research Center for Biological Structures, Tsinghua University, Beijing, 100084, China
| | - Yan Li
- Laboratory of Molecular Modeling and Design, State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Science, 457 Zhongshan Road, Dalian, 116023, China
| | - Xin Liang
- Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Guohui Li
- Laboratory of Molecular Modeling and Design, State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Science, 457 Zhongshan Road, Dalian, 116023, China
| | - Huiying Chu
- Laboratory of Molecular Modeling and Design, State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Science, 457 Zhongshan Road, Dalian, 116023, China.
| | - Hong-Wei Wang
- State Key Laboratory of Membrane Biology, Tsinghua University, Beijing, 100084, China.
- Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084, China.
- Beijing Frontier Research Center for Biological Structures, Tsinghua University, Beijing, 100084, China.
| |
Collapse
|
2
|
Zheng Y, Yang M, Chen X, Zhang G, Wan S, Zhang B, Huo J, Liu H. Decreased tubulin-binding cofactor B was involved in the formation disorder of nascent astrocyte processes by regulating microtubule plus-end growth through binding with end-binding proteins 1 and 3 after chronic alcohol exposure. Front Cell Neurosci 2022; 16:989945. [PMID: 36385945 PMCID: PMC9641617 DOI: 10.3389/fncel.2022.989945] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2022] [Accepted: 09/21/2022] [Indexed: 11/30/2022] Open
Abstract
Fetal alcohol syndrome (FAS) is a neurological disease caused by excessive drinking during pregnancy and characterized by congenital abnormalities in the structure and function of the fetal brain. This study was proposed to provide new insights into the pathogenesis of FAS by revealing the possible mechanisms of alcohol-induced astrocyte injury. First, a chronic alcohol exposure model of astrocytes was established, and the formation disorder was found in astrocyte processes where tubulin-binding cofactor B (TBCB) was decreased or lost, accompanied by disorganized microtubules (MT). Second, to understand the relationship between TBCB reduction and the formation disorder of astrocyte processes, TBCB was silenced or overexpressed. It caused astrocyte processes to retract or lose after silencing, while the processes increased with expending basal part and obtuse tips after overexpressing. It confirmed that TBCB was one of the critical factors for the formation of astrocyte processes through regulating MT plus-end and provided a new view on the pathogenesis of FAS. Third, to explore the mechanism of TBCB regulating MT plus-ends, we first proved end-binding proteins 1 and 3 (EB1/3) were bound at MT plus-ends in astrocytes. Then, through interference experiments, we found that both EB1 and EB3, which formed in heterodimers, were necessary to mediate TBCB binding to MT plus-ends and thus regulated the formation of astrocyte processes. Finally, the regulatory mechanism was studied and the ERK1/2 signaling pathway was found as one of the main pathways regulating the expression of TBCB in astrocytes after alcohol injury.
Collapse
Affiliation(s)
- Yin Zheng
- Institute of Neuroscience, Chongqing Medical University, Chongqing, China
- Department of Basic Medicine, Chongqing College of Traditional Chinese Medicine, Chongqing, China
| | - Mei Yang
- Institute of Neuroscience, Chongqing Medical University, Chongqing, China
| | - Xiaoqiao Chen
- Institute of Neuroscience, Chongqing Medical University, Chongqing, China
| | - Gaoli Zhang
- Institute for Viral Hepatitis, Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Shanshan Wan
- Department of Blood Transfusion, Sichuan Cancer Hospital and Institute, Chengdu, China
| | - Bingqiu Zhang
- Institute of Neuroscience, Chongqing Medical University, Chongqing, China
| | - Jiechao Huo
- Fujian Province University Engineering Research Center of Mindong She Medicine, Medical College, Ningde Normal University, Ningde, China
| | - Hui Liu
- Institute of Neuroscience, Chongqing Medical University, Chongqing, China
- *Correspondence: Hui Liu
| |
Collapse
|
3
|
Sulimenko V, Dráberová E, Dráber P. γ-Tubulin in microtubule nucleation and beyond. Front Cell Dev Biol 2022; 10:880761. [PMID: 36158181 PMCID: PMC9503634 DOI: 10.3389/fcell.2022.880761] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Accepted: 08/03/2022] [Indexed: 11/13/2022] Open
Abstract
Microtubules composed of αβ-tubulin dimers are dynamic cytoskeletal polymers that play key roles in essential cellular processes such as cell division, organelle positioning, intracellular transport, and cell migration. γ-Tubulin is a highly conserved member of the tubulin family that is required for microtubule nucleation. γ-Tubulin, together with its associated proteins, forms the γ-tubulin ring complex (γ-TuRC), that templates microtubules. Here we review recent advances in the structure of γ-TuRC, its activation, and centrosomal recruitment. This provides new mechanistic insights into the molecular mechanism of microtubule nucleation. Accumulating data suggest that γ-tubulin also has other, less well understood functions. We discuss emerging evidence that γ-tubulin can form oligomers and filaments, has specific nuclear functions, and might be involved in centrosomal cross-talk between microtubules and microfilaments.
Collapse
Affiliation(s)
| | | | - Pavel Dráber
- *Correspondence: Vadym Sulimenko, ; Pavel Dráber,
| |
Collapse
|
4
|
Zheng Y, Huo J, Yang M, Zhang G, Wan S, Chen X, Zhang B, Liu H. ERK1/2 Signalling Pathway Regulates Tubulin-Binding Cofactor B Expression and Affects Astrocyte Process Formation after Acute Foetal Alcohol Exposure. Brain Sci 2022; 12:brainsci12070813. [PMID: 35884621 PMCID: PMC9312805 DOI: 10.3390/brainsci12070813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2022] [Revised: 06/17/2022] [Accepted: 06/20/2022] [Indexed: 12/04/2022] Open
Abstract
Foetal alcohol spectrum disorders (FASDs) are a spectrum of neurological disorders whose neurological symptoms, besides the neuronal damage caused by alcohol, may also be associated with neuroglial damage. Tubulin-binding cofactor B (TBCB) may be involved in the pathogenesis of FASD. To understand the mechanism and provide new insights into the pathogenesis of FASD, acute foetal alcohol exposure model on astrocytes was established and the interference experiments were carried out. First, after alcohol exposure, the nascent astrocyte processes were reduced or lost, accompanied by the absence of TBCB expression and the disruption of microtubules (MTs) in processes. Subsequently, TBCB was silenced with siRNA. It was severely reduced or lost in nascent astrocyte processes, with a dramatic reduction in astrocyte processes, indicating that TBCB plays a vital role in astrocyte process formation. Finally, the regulating mechanism was studied and it was found that the extracellular signal-regulated protease 1/2 (ERK1/2) signalling pathway was one of the main pathways regulating TBCB expression in astrocytes after alcohol injury. In summary, after acute foetal alcohol exposure, the decreased TBCB in nascent astrocyte processes, regulated by the ERK1/2 signalling pathway, was the main factor leading to the disorder of astrocyte process formation, which could contribute to the neurological symptoms of FASD.
Collapse
Affiliation(s)
- Yin Zheng
- Institute of Neuroscience, Chongqing Medical University, Chongqing 400016, China; (M.Y.); (X.C.); (B.Z.); (H.L.)
- Correspondence: (Y.Z.); (J.H.)
| | - Jiechao Huo
- Institute of Neuroscience, Chongqing Medical University, Chongqing 400016, China; (M.Y.); (X.C.); (B.Z.); (H.L.)
- Correspondence: (Y.Z.); (J.H.)
| | - Mei Yang
- Institute of Neuroscience, Chongqing Medical University, Chongqing 400016, China; (M.Y.); (X.C.); (B.Z.); (H.L.)
| | - Gaoli Zhang
- Institute for Viral Hepatitis, Second Affiliated Hospital of Chongqing Medical University, Chongqing 400063, China;
| | - Shanshan Wan
- Department of Blood Transfusion, Sichuan Cancer Hospital & Institute, Chengdu 610044, China;
| | - Xiaoqiao Chen
- Institute of Neuroscience, Chongqing Medical University, Chongqing 400016, China; (M.Y.); (X.C.); (B.Z.); (H.L.)
| | - Bingqiu Zhang
- Institute of Neuroscience, Chongqing Medical University, Chongqing 400016, China; (M.Y.); (X.C.); (B.Z.); (H.L.)
| | - Hui Liu
- Institute of Neuroscience, Chongqing Medical University, Chongqing 400016, China; (M.Y.); (X.C.); (B.Z.); (H.L.)
| |
Collapse
|
5
|
Hoff KJ, Aiken JE, Gutierrez MA, Franco SJ, Moore JK. Tubulinopathy mutations in TUBA1A that disrupt neuronal morphogenesis and migration override XMAP215/Stu2 regulation of microtubule dynamics. eLife 2022; 11:76189. [PMID: 35511030 PMCID: PMC9236607 DOI: 10.7554/elife.76189] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 04/29/2022] [Indexed: 11/13/2022] Open
Abstract
Heterozygous, missense mutations in α- or β-tubulin genes are associated with a wide range of human brain malformations, known as tubulinopathies. We seek to understand whether a mutation’s impact at the molecular and cellular levels scale with the severity of brain malformation. Here, we focus on two mutations at the valine 409 residue of TUBA1A, V409I, and V409A, identified in patients with pachygyria or lissencephaly, respectively. We find that ectopic expression of TUBA1A-V409I/A mutants disrupt neuronal migration in mice and promote excessive neurite branching and a decrease in the number of neurite retraction events in primary rat neuronal cultures. These neuronal phenotypes are accompanied by increased microtubule acetylation and polymerization rates. To determine the molecular mechanisms, we modeled the V409I/A mutants in budding yeast and found that they promote intrinsically faster microtubule polymerization rates in cells and in reconstitution experiments with purified tubulin. In addition, V409I/A mutants decrease the recruitment of XMAP215/Stu2 to plus ends in budding yeast and ablate tubulin binding to TOG (tumor overexpressed gene) domains. In each assay tested, the TUBA1A-V409I mutant exhibits an intermediate phenotype between wild type and the more severe TUBA1A-V409A, reflecting the severity observed in brain malformations. Together, our data support a model in which the V409I/A mutations disrupt microtubule regulation typically conferred by XMAP215 proteins during neuronal morphogenesis and migration, and this impact on tubulin activity at the molecular level scales with the impact at the cellular and tissue levels. Proteins are molecules made up of long chains of building blocks called amino acids. When a mutation changes one of these amino acids, it can lead to the protein malfunctioning, which can have many effects at the cell and tissue level. Given that human proteins are made up of 20 different amino acids, each building block in a protein could mutate to any of the other 19 amino acids, and each mutations could have different effects. Tubulins are proteins that form microtubules, thin tubes that help give cells their shape and allow them to migrate. These proteins are added or removed to microtubules depending on the cell’s needs, meaning that microtubules can grow or shrink depending on the situation. Mutations in the tubulin proteins have been linked to malformations of varying severities involving the formation of ridges and folds on the surface of the brain, including lissencephaly, pachygyria or polymicrogyria. Hoff et al. wanted to establish links between tubulin mutations and the effects observed at both cell and tissue level in the brain. They focused on two mutations in the tubulin protein TUBA1A that affect the amino acid in position 409 in the protein, which is normally a valine. One of the mutations turns this valine into an amino acid called isoleucine. This mutation is associated with pachygyria, which leads to the brain developing few ridges that are broad and flat. The second mutation turns the valine into an alanine, and is linked to lissencephaly, a more severe condition in which the brain develops no ridges, appearing smooth. Hoff et al. found that both mutations interfere with the development of the brain by stopping neurons from migrating properly, which prevents them from forming the folds in the brain correctly. At the cellular level, the mutations lead to tubulins becoming harder to remove from microtubules, making microtubules more stable than usual. This results in longer microtubules that are harder for the cell to shorten or destroy as needed. Additionally, Hoff et al. showed that the mutant versions of TUBA1A have weaker interactions with a protein called XMAP215, which controls the addition of tubulin to microtubules. This causes the microtubules to grow uncontrollably. Hoff et al. also established that the magnitude of the effects of each mutation on microtubule growth scale with the severity of the disorder they cause. Specifically, cells in which TUBA1A is not mutated have microtubules that grow at a normal rate, and lead to typical brain development. Meanwhile, cells carrying the mutation that turns a valine into an alanine, which is linked to the more severe condition lissencephaly, have microtubules that grow very fast. Finally, cells in which the valine is mutated to an isoleucine – the mutation associated with the less severe malformation pachygyria – have microtubules that grow at an intermediate rate. These findings provide a link between mutations in tubulin proteins and larger effects on cell movement that lead to brain malformations. Additionally, they also link the severity of the malformation to the severity of the microtubule defect caused by each mutation. Further work could examine whether microtubule stabilization is also seen in other similar diseases, which, in the long term, could reveal ways to detect and treat these illnesses.
Collapse
Affiliation(s)
- Katelyn J Hoff
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, United States
| | - Jayne E Aiken
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, United States
| | - Mark A Gutierrez
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, United States
| | - Santos J Franco
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, United States
| | - Jeffrey K Moore
- University of Colorado School of Medicine, Aurora, United States
| |
Collapse
|
6
|
Wang J, Miller DD, Li W. Molecular interactions at the colchicine binding site in tubulin: An X-ray crystallography perspective. Drug Discov Today 2022; 27:759-776. [PMID: 34890803 PMCID: PMC8901563 DOI: 10.1016/j.drudis.2021.12.001] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 07/27/2021] [Accepted: 12/02/2021] [Indexed: 01/02/2023]
Abstract
Tubulin is an important cancer drug target. Compounds that bind at the colchicine site in tubulin have attracted significant interest as they are generally less affected by multidrug resistance than other potential drugs. Modeling is useful in understanding the interactions between tubulin and colchicine binding site inhibitors (CBSIs), but because the colchicine binding site contains two flexible loops whose conformations are highly ligand-dependent, modeling has its limitations. X-ray crystallography provides experimental pictures of tubulin-ligand interactions at this challenging colchicine site. Since 2004, when the first X-ray structure of tubulin in complex with N-deacetyl-N-(2-mercaptoacetyl)-colchicine (DAMA-colchicine) was published, many X-ray crystal structures have been reported for tubulin complexes involving the colchicine binding site. In this review, we summarize the crystal structures of tubulin in complexes with various CBSIs, aiming to facilitate the discovery of new generations of tubulin inhibitors.
Collapse
Affiliation(s)
| | | | - Wei Li
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, Memphis, TN 38163, USA.
| |
Collapse
|
7
|
Kurisaki I, Tanaka S. Elucidating microscopic events driven by GTP hydrolysis reaction in the Ras-GAP system with semi-reactive molecular dynamics simulations: the alternative role of a phosphate binding loop for mechanical energy storage. Phys Chem Chem Phys 2021; 23:26151-26164. [PMID: 34797363 DOI: 10.1039/d1cp04061h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
ATPase and GTPase have been widely found as chemical energy-mechanical work transducers, whereas the physicochemical mechanisms are not satisfactorily understood. We addressed the problem by examining John Ross' conjecture that repulsive Coulomb interaction between ADP/GDP and inorganic phosphate (Pi) does the mechanical work upon the system. We effectively simulated the consequence of a GTP hydrolysis reaction in a complex system of Rat sarcoma (Ras) and GTPase activation protein (GAP) in the framework of classical molecular dynamics by switching force field parameters between the reactant and product systems. We then observed a ca. 5 kcal mol-1 increase of potential energy about the phosphate-binding loop (P-loop) in the Ras protein, indicating that the mechanical work generated via the GTP hydrolysis is converted into the local interaction energy and stored in the P-loop. Interestingly, this local energy storage in the P-loop depends on neither impulsive nor consecutive collisions of GDP and Pi with the P-loop. Instead, GTP-GDP conversion itself does work on the Ras system, elevating the potential energy. These observations encourage us to challenge a conjecture previously given by Ross. We assert that triphosphate nucleotide hydrolyses do mechanical work by producing emergent steric interaction accompanied by relaxation, namely, a shift of the biomolecular system to the non-equilibrium state on the reshaped potential energy landscape. Recalling the universality of the P-loop motif among GTPases and ATPases, the observations that we obtained through this study would progress the physicochemical understanding of the operating principles of GTP/ATP hydrolysis-driven biological nano-machines.
Collapse
Affiliation(s)
- Ikuo Kurisaki
- Department of Computational Science, Graduate School of System Informatics, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe 657-8501, Japan.
| | - Shigenori Tanaka
- Department of Computational Science, Graduate School of System Informatics, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe 657-8501, Japan.
| |
Collapse
|
8
|
Shemesh A, Ginsburg A, Dharan R, Levi-Kalisman Y, Ringel I, Raviv U. Structure and Energetics of GTP- and GDP-Tubulin Isodesmic Self-Association. ACS Chem Biol 2021; 16:2212-2227. [PMID: 34643366 DOI: 10.1021/acschembio.1c00369] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Tubulin self-association is a critical process in microtubule dynamics. The early intermediate structures, energetics, and their regulation by fluxes of chemical energy, associated with guanosine triphosphate (GTP) hydrolysis, are poorly understood. We reconstituted an in vitro minimal model system, mimicking the key elements of the nontemplated tubulin assembly. To resolve the distribution of GTP- and guanosine diphosphate (GDP)-tubulin structures, at low temperatures (∼10 °C) and below the critical concentration for the microtubule assembly, we analyzed in-line size-exclusion chromatography-small-angle X-ray scattering (SEC-SAXS) chromatograms of GTP- and GDP-tubulin solutions. Both solutions rapidly attained steady state. The SEC-SAXS data were consistent with an isodesmic thermodynamic model of longitudinal tubulin self-association into 1D oligomers, terminated by the formation of tubulin single rings. The analysis showed that free dimers coexisted with tetramers and hexamers. Tubulin monomers and lateral association between dimers were not detected. The dimer-dimer longitudinal self-association standard Helmholtz free energies were -14.2 ± 0.4 kBT (-8.0 ± 0.2 kcal mol-1) and -13.1 ± 0.5 kBT (-7.4 ± 0.3 kcal mol-1) for GDP- and GTP-tubulin, respectively. We then determined the mass fractions of dimers, tetramers, and hexamers as a function of the total tubulin concentration. A small fraction of stable tubulin single rings, with a radius of 19.2 ± 0.2 nm, was detected in the GDP-tubulin solution. In the GTP-tubulin solution, this fraction was significantly lower. Cryo-TEM images and SEC-multiangle light-scattering analysis corroborated these findings. Our analyses provide an accurate structure-stability description of cold tubulin solutions.
Collapse
Affiliation(s)
- Asaf Shemesh
- Institute of Chemistry, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, Jerusalem 9190401, Israel
- The Harvey M. Krueger Family Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat
Ram, Jerusalem 9190401, Israel
| | - Avi Ginsburg
- Institute of Chemistry, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, Jerusalem 9190401, Israel
| | - Raviv Dharan
- Institute of Chemistry, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, Jerusalem 9190401, Israel
| | - Yael Levi-Kalisman
- The Harvey M. Krueger Family Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat
Ram, Jerusalem 9190401, Israel
- Institute of Life Sciences, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, Jerusalem 9190401, Israel
| | - Israel Ringel
- Institute for Drug Research, The School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Ein Karem, Jerusalem 9112102, Israel
| | - Uri Raviv
- Institute of Chemistry, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, Jerusalem 9190401, Israel
- The Harvey M. Krueger Family Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat
Ram, Jerusalem 9190401, Israel
| |
Collapse
|
9
|
Dráber P, Dráberová E. Dysregulation of Microtubule Nucleating Proteins in Cancer Cells. Cancers (Basel) 2021; 13:cancers13225638. [PMID: 34830792 PMCID: PMC8616210 DOI: 10.3390/cancers13225638] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 11/06/2021] [Accepted: 11/08/2021] [Indexed: 12/12/2022] Open
Abstract
Simple Summary The dysfunction of microtubule nucleation in cancer cells changes the overall cytoskeleton organization and cellular physiology. This review focuses on the dysregulation of the γ-tubulin ring complex (γ-TuRC) proteins that are essential for microtubule nucleation. Recent research on the high-resolution structure of γ-TuRC has brought new insight into the microtubule nucleation mechanism. We discuss the effect of γ-TuRC protein overexpression on cancer cell behavior and new drugs directed to γ-tubulin that may offer a viable alternative to microtubule-targeting agents currently used in cancer chemotherapy. Abstract In cells, microtubules typically nucleate from microtubule organizing centers, such as centrosomes. γ-Tubulin, which forms multiprotein complexes, is essential for nucleation. The γ-tubulin ring complex (γ-TuRC) is an efficient microtubule nucleator that requires additional centrosomal proteins for its activation and targeting. Evidence suggests that there is a dysfunction of centrosomal microtubule nucleation in cancer cells. Despite decades of molecular analysis of γ-TuRC and its interacting factors, the mechanisms of microtubule nucleation in normal and cancer cells remains obscure. Here, we review recent work on the high-resolution structure of γ-TuRC, which brings new insight into the mechanism of microtubule nucleation. We discuss the effects of γ-TuRC protein dysregulation on cancer cell behavior and new compounds targeting γ-tubulin. Drugs inhibiting γ-TuRC functions could represent an alternative to microtubule targeting agents in cancer chemotherapy.
Collapse
|
10
|
Pathomechanisms of Paclitaxel-Induced Peripheral Neuropathy. TOXICS 2021; 9:toxics9100229. [PMID: 34678925 PMCID: PMC8540213 DOI: 10.3390/toxics9100229] [Citation(s) in RCA: 58] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 09/09/2021] [Accepted: 09/16/2021] [Indexed: 12/18/2022]
Abstract
Peripheral neuropathy is one of the most common side effects of chemotherapy, affecting up to 60% of all cancer patients receiving chemotherapy. Moreover, paclitaxel induces neuropathy in up to 97% of all gynecological and urological cancer patients. In cancer cells, paclitaxel induces cell death via microtubule stabilization interrupting cell mitosis. However, paclitaxel also affects cells of the central and peripheral nervous system. The main symptoms are pain and numbness in hands and feet due to paclitaxel accumulation in the dorsal root ganglia. This review describes in detail the pathomechanisms of paclitaxel in the peripheral nervous system. Symptoms occur due to a length-dependent axonal sensory neuropathy, where axons are symmetrically damaged and die back. Due to microtubule stabilization, axonal transport is disrupted, leading to ATP undersupply and oxidative stress. Moreover, mitochondria morphology is altered during paclitaxel treatment. A key player in pain sensation and axonal damage is the paclitaxel-induced inflammation in the spinal cord as well as the dorsal root ganglia. An increased expression of chemokines and cytokines such as IL-1β, IL-8, and TNF-α, but also CXCR4, RAGE, CXCL1, CXCL12, CX3CL1, and C3 promote glial activation and accumulation, and pain sensation. These findings are further elucidated in this review.
Collapse
|
11
|
Abstract
Since their discovery more than 100 years ago, the viruses that infect bacteria (bacteriophages) have been widely studied as model systems. Largely overlooked, however, have been "jumbo phages," with genome sizes ranging from 200 to 500 kbp. Jumbo phages generally have large virions with complex structures and a broad host spectrum. While the majority of jumbo phage genes are poorly functionally characterized, recent work has discovered many unique biological features, including a conserved tubulin homolog that coordinates a proteinaceous nucleus-like compartment that houses and segregates phage DNA. The tubulin spindle displays dynamic instability and centers the phage nucleus within the bacterial host during phage infection for optimal reproduction. The shell provides robust physical protection for the enclosed phage genomes against attack from DNA-targeting bacterial immune systems, thereby endowing jumbo phages with broad resistance. In this review, we focus on the current knowledge of the cytoskeletal elements and the specialized nuclear compartment derived from jumbo phages, and we highlight their importance in facilitating spatial and temporal organization over the viral life cycle. Additionally, we discuss the evolutionary relationships between jumbo phages and eukaryotic viruses, as well as the therapeutic potential and drawbacks of jumbo phages as antimicrobial agents in phage therapy.
Collapse
|
12
|
Lee J, Song C, Lee J, Miller HP, Cho H, Gim B, Li Y, Feinstein SC, Wilson L, Safinya CR, Choi MC. Tubulin Double Helix: Lateral and Longitudinal Curvature Changes of Tubulin Protofilament. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2020; 16:e2001240. [PMID: 32794304 DOI: 10.1002/smll.202001240] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 07/14/2020] [Indexed: 06/11/2023]
Abstract
By virtue of their native structures, tubulin dimers are protein building blocks that are naturally preprogrammed to assemble into microtubules (MTs), which are cytoskeletal polymers. Here, polycation-directed (i.e., electrostatically tunable) assembly of tubulins is demonstrated by conformational changes to the tubulin protofilament in longitudinal and lateral directions, creating tubulin double helices and various tubular architectures. Synchrotron small-angle X-ray scattering and transmission electron microscopy reveal a remarkable range of nanoscale assembly structures: single- and double-layered double-helix tubulin tubules. The phase transitions from MTs to the new assemblies are dependent on the size and concentration of polycations. Two characteristic scales that determine the number of observed phases are the size of polycation compared to the size of tubulin (≈4 nm) and to MT diameter (≈25 nm). This work suggests the feasibility of using polycations that have scissor- and glue-like properties to achieve "programmable breakdown" of protein nanotubes, tearing MTs into double-stranded tubulins and building up previously undiscovered nanostructures. Importantly, a new role of tubulins is defined as 2D shape-controllable building blocks for supramolecular architectures. These findings provide insight into the design of protein-based functional materials, for example, as metallization templates for nanoscale electronic devices, molecular screws, and drug delivery vehicles.
Collapse
Affiliation(s)
- Juncheol Lee
- Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Daejeon, 34141, South Korea
| | - Chaeyeon Song
- Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Daejeon, 34141, South Korea
| | - Jimin Lee
- Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Daejeon, 34141, South Korea
| | - Herbert P Miller
- Molecular, Cellular and Developmental Biology Department and Neuroscience Research Institute, University of California, Santa Barbara, CA, 93106, USA
| | - Hasaeam Cho
- Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Daejeon, 34141, South Korea
| | - Bopil Gim
- Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Daejeon, 34141, South Korea
| | - Youli Li
- Materials Research Laboratory, University of California, Santa Barbara, CA, 93106, USA
| | - Stuart C Feinstein
- Molecular, Cellular and Developmental Biology Department and Neuroscience Research Institute, University of California, Santa Barbara, CA, 93106, USA
| | - Leslie Wilson
- Molecular, Cellular and Developmental Biology Department and Neuroscience Research Institute, University of California, Santa Barbara, CA, 93106, USA
| | - Cyrus R Safinya
- Materials, Physics, Molecular, Cellular and Developmental Biology Departments, University of California, Santa Barbara, CA, 93106, USA
| | - Myung Chul Choi
- Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Daejeon, 34141, South Korea
| |
Collapse
|
13
|
Tong D, Voth GA. Microtubule Simulations Provide Insight into the Molecular Mechanism Underlying Dynamic Instability. Biophys J 2020; 118:2938-2951. [PMID: 32413312 DOI: 10.1016/j.bpj.2020.04.028] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 04/20/2020] [Accepted: 04/24/2020] [Indexed: 12/14/2022] Open
Abstract
The dynamic instability of microtubules (MTs), which refers to their ability to switch between polymerization and depolymerization states, is crucial for their function. It has been proposed that the growing MT ends are protected by a "GTP cap" that consists of GTP-bound tubulin dimers. When the speed of GTP hydrolysis is faster than dimer recruitment, the loss of this GTP cap will lead the MT to undergo rapid disassembly. However, the underlying atomistic mechanistic details of the dynamic instability remains unclear. In this study, we have performed long-time atomistic molecular dynamics simulations (1 μs for each system) for MT patches as well as a short segment of a closed MT in both GTP- and GDP-bound states. Our results confirmed that MTs in the GDP state generally have weaker lateral interactions between neighboring protofilaments (PFs) and less cooperative outward bending conformational change, where the difference between bending angles of neighboring PFs tends to be larger compared with GTP ones. As a result, when the GDP state tubulin dimer is exposed at the growing MT end, these factors will be more likely to cause the MT to undergo rapid disassembly. We also compared simulation results between the special MT seam region and the remaining material and found that the lateral interactions between MT PFs at the seam region were comparatively much weaker. This finding is consistent with the experimental suggestion that the seam region tends to separate during the disassembly process of an MT.
Collapse
Affiliation(s)
- Dudu Tong
- Department of Chemistry, Chicago Center for Theoretical Chemistry, James Franck Institute, and Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois
| | - Gregory A Voth
- Department of Chemistry, Chicago Center for Theoretical Chemistry, James Franck Institute, and Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois.
| |
Collapse
|
14
|
Han H, Schubert HL, McCullough J, Monroe N, Purdy MD, Yeager M, Sundquist WI, Hill CP. Structure of spastin bound to a glutamate-rich peptide implies a hand-over-hand mechanism of substrate translocation. J Biol Chem 2019; 295:435-443. [PMID: 31767681 DOI: 10.1074/jbc.ac119.009890] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 11/11/2019] [Indexed: 11/06/2022] Open
Abstract
Many members of the AAA+ ATPase family function as hexamers that unfold their protein substrates. These AAA unfoldases include spastin, which plays a critical role in the architecture of eukaryotic cells by driving the remodeling and severing of microtubules, which are cytoskeletal polymers of tubulin subunits. Here, we demonstrate that a human spastin binds weakly to unmodified peptides from the C-terminal segment of human tubulin α1A/B. A peptide comprising alternating glutamate and tyrosine residues binds more tightly, which is consistent with the known importance of glutamylation for spastin microtubule severing activity. A cryo-EM structure of the spastin-peptide complex at 4.2 Å resolution revealed an asymmetric hexamer in which five spastin subunits adopt a helical, spiral staircase configuration that binds the peptide within the central pore, whereas the sixth subunit of the hexamer is displaced from the peptide/substrate, as if transitioning from one end of the helix to the other. This configuration differs from a recently published structure of spastin from Drosophila melanogaster, which forms a six-subunit spiral without a transitioning subunit. Our structure resembles other recently reported AAA unfoldases, including the meiotic clade relative Vps4, and supports a model in which spastin utilizes a hand-over-hand mechanism of tubulin translocation and microtubule remodeling.
Collapse
Affiliation(s)
- Han Han
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, Utah 84112
| | - Heidi L Schubert
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, Utah 84112
| | - John McCullough
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, Utah 84112
| | - Nicole Monroe
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, Utah 84112
| | - Michael D Purdy
- Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, Virginia 22908
| | - Mark Yeager
- Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, Virginia 22908; Department of Medicine, Division of Cardiovascular Medicine, University of Virginia School of Medicine, Charlottesville, Virginia 22908; Center for Membrane and Cell Physiology, University of Virginia School of Medicine, Charlottesville, Virginia 22908; Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia 22908
| | - Wesley I Sundquist
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, Utah 84112.
| | - Christopher P Hill
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, Utah 84112.
| |
Collapse
|
15
|
Li M, Mao L, Chen M, Li M, Wang K, Mo J. Characterization of an Amphiphilic Phosphonated Calixarene Carrier Loaded With Carboplatin and Paclitaxel: A Preliminary Study to Treat Colon Cancer in vitro and in vivo. Front Bioeng Biotechnol 2019; 7:238. [PMID: 31632958 PMCID: PMC6779836 DOI: 10.3389/fbioe.2019.00238] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Accepted: 09/11/2019] [Indexed: 12/20/2022] Open
Abstract
The inadequacy of available detection methods and a naturally aggressive progression have made colon cancer the third most common type of cancer, accounting for ~10% of all cancer cases. The heterogeneity and genomic instability of colon cancer tumors make current treatments unsatisfactory. This study evaluated a novel nanoscale delivery platform comprising phosphonated calixarenes (P4C6) co-loaded with paclitaxel (PTX) and carboplatin (CPT). The nanoparticles showed average hydrodynamic sizes of 84 ± 8 nm for empty P4C6 nanoparticle and 119 ± 13 nm for PTX-CPT-P4C6. The corresponding zeta potentials were −40.8 ± 8.8 and −35.4 ± 4.2 mV. The optimal CPT:PTX ratio was 5.22:1, and PTX-CPT-P4C6 with this ratio was more cytotoxic against HT-29 cells than against Caco-2 cells (IC50, 0.4 ± 0.02 vs. 2.1 ± 0.3 μM), and it induced higher apoptosis in HT-29 cells (56.6 ± 4.5 vs. 44.9 ± 3.44%). PTX-CPT-P4C6 inhibited the invasion and migration of HT-29 cells more strongly than the free drugs. It also inhibited the growth of HT-29 tumors in mice to the greatest extent of all formulations, with negligible side effects. This research demonstrates the potential of P4C6 to deliver two chemotherapeutic agents to colon cancer tumors to provide synergistic efficacy than single drug administration.
Collapse
Affiliation(s)
- Meiying Li
- Clinical Research Center for Neurological Diseases of Guangxi Province, Affiliated Hospital of Guilin Medical University, Guilin, China.,School of Pharmacy, Guilin Medical University, Guilin, China
| | - Liujun Mao
- Department of Further-Education, Affiliated Hospital of Guilin Medical University, Guilin, China
| | - Meirong Chen
- Department of Graduate, Affiliated Hospital of Guilin Medical University, Guilin, China
| | - Mingxin Li
- School of Pharmacy, Guilin Medical University, Guilin, China
| | - Kaixuan Wang
- School of Pharmacy, Guilin Medical University, Guilin, China
| | - Jingxin Mo
- Clinical Research Center for Neurological Diseases of Guangxi Province, Affiliated Hospital of Guilin Medical University, Guilin, China
| |
Collapse
|
16
|
Kaneshiro J, Okada Y, Shima T, Tsujii M, Imada K, Ichimura T, Watanabe TM. Second harmonic generation polarization microscopy as a tool for protein structure analysis. Biophys Physicobiol 2019; 16:147-157. [PMID: 31660282 PMCID: PMC6812877 DOI: 10.2142/biophysico.16.0_147] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Accepted: 08/17/2019] [Indexed: 01/05/2023] Open
Abstract
Cryo-electron microscopy and X-ray crystallography have been the major tools of protein structure analysis for decades and will certainly continue to be essential in the future. Moreover, nuclear magnetic resonance or Förster resonance energy transfer can measure structural dynamics. Here, we propose to add optical second-harmonic generation (SHG), which is a nonlinear optical scattering process sensitive to molecular structures in illuminated materials, to the tool-kit of structural analysis methodologies. SHG can be expected to probe the structural changes of proteins in the physiological condition, and thus link protein structure and biological function. We demonstrate that a conformational change as well as its dynamics in protein macromolecular assemblies can be detected by means of SHG polarization measurement. To prove the capability of SHG polarization measurement with regard to protein structure analysis, we developed an SHG polarization microscope to analyze microtubules in solution. The difference in conformation between microtubules with different binding molecules was successfully observed as polarization dependence of SHG intensity. We also succeeded in capturing the temporal variation of structure in a photo-switchable protein crystal in both activation and inactivation processes. These results illustrate the potential of this method for protein structure analysis in physiological solutions at room temperature without any labeling.
Collapse
Affiliation(s)
- Junichi Kaneshiro
- Laboratory for Comprehensive Bioimaging, RIKEN Center for Biosystems Dynamics Research (BDR), Suita, Osaka 565-0874, Japan
| | - Yasushi Okada
- Laboratory for Cell Polarity Regulation, RIKEN Center for Biosystems Dynamics Research (BDR), Suita, Osaka 565-0874, Japan.,Department of Physics and Universal Biology Institute (UBI), Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Tomohiro Shima
- Laboratory for Cell Polarity Regulation, RIKEN Center for Biosystems Dynamics Research (BDR), Suita, Osaka 565-0874, Japan
| | - Mika Tsujii
- Department of Macromolecular Science, Graduate School of Science, Osaka University, Toyonaka, Osaka 565-0043, Japan
| | - Katsumi Imada
- Department of Macromolecular Science, Graduate School of Science, Osaka University, Toyonaka, Osaka 565-0043, Japan
| | - Taro Ichimura
- Laboratory for Comprehensive Bioimaging, RIKEN Center for Biosystems Dynamics Research (BDR), Suita, Osaka 565-0874, Japan.,Transdimensional Life Imaging Division, Institute for Open and Transdisciplinary Research Initiatives (OTRI), Osaka University, Suita, Osaka 565-0871, Japan.,PRESTO, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012, Japan
| | - Tomonobu M Watanabe
- Laboratory for Comprehensive Bioimaging, RIKEN Center for Biosystems Dynamics Research (BDR), Suita, Osaka 565-0874, Japan
| |
Collapse
|
17
|
Jing D, Li D, Peng C, Chen Y, Behnisch T. Role of microtubules in late-associative plasticity of hippocampal Schaffer collateral-CA1 synapses in mice. Neurobiol Learn Mem 2019; 163:107038. [PMID: 31278986 DOI: 10.1016/j.nlm.2019.107038] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Revised: 04/13/2019] [Accepted: 07/02/2019] [Indexed: 11/17/2022]
Abstract
The microtubule network represents a key scaffolding structure that forms part of the neuronal cytoskeleton and contributes to biomolecule exchange within neurons. However, researchers have not determined whether an intact microtubule network is required for late associative plasticity. Therefore, the late associative plasticity of field excitatory postsynaptic potentials from two synaptic inputs was analyzed. Synaptic potentiation was induced through alternating tetanization of hippocampal Schaffer-collateral CA1 synaptic populations in acute slices prepared from young-adult C57BL/6 mice. Vincristine was applied to depolymerize microtubules. Vincristine did not alter the phosphorylation levels of plasticity-related pre- or postsynaptic proteins but reduced the level of a protein marker of the ER-Golgi intermediate compartment (ERGIC-53/p58). Vincristine did not alter the magnitude or maintenance of the synaptic potentiation evoked by repeated tetanization (3 × 100 stimuli at 100 Hz) of one synaptic population. However, this synaptic potentiation was sensitive to the coapplication of a protein synthesis inhibitor, such as rapamycin, anisomycin or cycloheximide, indicating that protein synthesis has become essential in depolymerized microtubules during the first hour of the synaptic potentiation. The application of vincristine up to a 70 stimuli, 100 Hz tetanization of a second synaptic input prevented the transformation of short-term potentiation into long-term potentiation (LTP), further indicating that intact microtubules are required for the late associative properties of synaptic plasticity. Therefore, activity-dependent synaptic plasticity does not rely on microtubules within the first two hours after tetanization; however, the associative interaction of independent synaptic inputs relies on their proper function. In addition, either new protein synthesis or microtubule-based processes are sufficient to stabilize LTP within the first 3 h after tetanization, and a deficit in synaptic plasticity is only observable when both processes are blocked.
Collapse
Affiliation(s)
- Dongqing Jing
- Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Fudan University, Shanghai, China
| | - Dongxue Li
- Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Fudan University, Shanghai, China
| | - Cheng Peng
- Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Fudan University, Shanghai, China
| | - Ying Chen
- Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Fudan University, Shanghai, China
| | - Thomas Behnisch
- Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Fudan University, Shanghai, China.
| |
Collapse
|
18
|
Orbach R, Howard J. The dynamic and structural properties of axonemal tubulins support the high length stability of cilia. Nat Commun 2019; 10:1838. [PMID: 31015426 PMCID: PMC6479064 DOI: 10.1038/s41467-019-09779-6] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 03/25/2019] [Indexed: 12/31/2022] Open
Abstract
Cilia and flagella play essential roles in cell motility, sensing and development. These organelles have tightly controlled lengths, and the axoneme, which forms the core structure, has exceptionally high stability. This is despite being composed of microtubules that are often characterized as highly dynamic. To understand how ciliary tubulin contribute to stability, we develop a procedure to differentially extract tubulins from different components of axonemes purified from Chlamydomonas reinhardtii, and characterize their properties. We find that the microtubules support length stability by two distinct mechanisms: low dynamicity, and unusual stability of the protofilaments. The high stability of the protofilaments manifests itself in the formation of curved tip structures, up to a few microns long. These structures likely reflect intrinsic curvature of GTP or GDP·Pi tubulin and provide structural insights into the GTP-cap. Together, our study provides insights into growth, stability and the role of post-translational modifications of axonemal microtubules. The axoneme in cilia and flagella has exceptionally high stability despite being composed of microtubules that are known to be highly dynamic. Here authors extract tubulin from different components of Chlamydomonas reinhardtii axonemes and characterize their properties.
Collapse
Affiliation(s)
- Ron Orbach
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Jonathon Howard
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA.
| |
Collapse
|
19
|
Abstract
DNA tiles provide a promising technique for assembling structures with nanoscale resolution through self-assembly by basic interactions rather than top-down assembly of individual structures. Tile systems can be programmed to grow based on logical rules, allowing for a small number of tile types to assemble large, complex assemblies that can retain nanoscale resolution. Such algorithmic systems can even assemble different structures using the same tiles, based on inputs that seed the growth. While programming and theoretical analysis of tile self-assembly often makes use of abstract logical models of growth, experimentally implemented systems are governed by nanoscale physical processes that can lead to very different behavior, more accurately modeled by taking into account the thermodynamics and kinetics of tile attachment and detachment in solution. This review discusses the relationships between more abstract and more physically realistic tile assembly models. A central concern is how consideration of model differences enables the design of tile systems that robustly exhibit the desired abstract behavior in realistic physical models and in experimental implementations. Conversely, we identify situations where self-assembly in abstract models can not be well-approximated by physically realistic models, putting constraints on physical relevance of the abstract models. To facilitate the discussion, we introduce a unified model of tile self-assembly that clarifies the relationships between several well-studied models in the literature. Throughout, we highlight open questions regarding the physical principles for DNA tile self-assembly.
Collapse
Affiliation(s)
- Constantine G Evans
- Evans Foundation for Molecular Medicine and California Institute of Technology, Physics, Pasadena, CA, USA
| | | |
Collapse
|
20
|
Kinetochore-microtubule interactions in chromosome segregation: lessons from yeast and mammalian cells. Biochem J 2017; 474:3559-3577. [PMID: 29046344 DOI: 10.1042/bcj20170518] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Revised: 08/24/2017] [Accepted: 09/11/2017] [Indexed: 02/06/2023]
Abstract
Chromosome congression and segregation require robust yet dynamic attachment of the kinetochore with the spindle microtubules. Force generated at the kinetochore-microtubule interface plays a vital role to drive the attachment, as it is required to move chromosomes and to provide signal to sense correct attachments. To understand the mechanisms underlying these processes, it is critical to describe how the force is generated and how the molecules at the kinetochore-microtubule interface are organized and assembled to withstand the force and respond to it. Research in the past few years or so has revealed interesting insights into the structural organization and architecture of kinetochore proteins that couple kinetochore attachment to the spindle microtubules. Interestingly, despite diversities in the molecular players and their modes of action, there appears to be architectural similarity of the kinetochore-coupling machines in lower to higher eukaryotes. The present review focuses on the most recent advances in understanding of the molecular and structural aspects of kinetochore-microtubule interaction based on the studies in yeast and vertebrate cells.
Collapse
|
21
|
Abstract
FtsZ, a homolog of tubulin, is found in almost all bacteria and archaea where it has a primary role in cytokinesis. Evidence for structural homology between FtsZ and tubulin came from their crystal structures and identification of the GTP box. Tubulin and FtsZ constitute a distinct family of GTPases and show striking similarities in many of their polymerization properties. The differences between them, more so, the complexities of microtubule dynamic behavior in comparison to that of FtsZ, indicate that the evolution to tubulin is attributable to the incorporation of the complex functionalities in higher organisms. FtsZ and microtubules function as polymers in cell division but their roles differ in the division process. The structural and partial functional homology has made the study of their dynamic properties more interesting. In this review, we focus on the application of the information derived from studies on FtsZ dynamics to study microtubule dynamics and vice versa. The structural and functional aspects that led to the establishment of the homology between the two proteins are explained to emphasize the network of FtsZ and microtubule studies and how they are connected.
Collapse
Affiliation(s)
- Rachana Rao Battaje
- Department of Biosciences and BioengineeringIndian Institute of Technology Bombay, Mumbai, India
| | - Dulal Panda
- Department of Biosciences and BioengineeringIndian Institute of Technology Bombay, Mumbai, India
| |
Collapse
|
22
|
Tubulin Inhibitor-Based Antibody-Drug Conjugates for Cancer Therapy. Molecules 2017; 22:molecules22081281. [PMID: 28763044 PMCID: PMC6152078 DOI: 10.3390/molecules22081281] [Citation(s) in RCA: 119] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Accepted: 07/29/2017] [Indexed: 11/16/2022] Open
Abstract
Antibody-drug conjugates (ADCs) are a class of highly potent biopharmaceutical drugs generated by conjugating cytotoxic drugs with specific monoclonal antibodies through appropriate linkers. Specific antibodies used to guide potent warheads to tumor tissues can effectively reduce undesired side effects of the cytotoxic drugs. An in-depth understanding of antibodies, linkers, conjugation strategies, cytotoxic drugs, and their molecular targets has led to the successful development of several approved ADCs. These ADCs are powerful therapeutics for cancer treatment, enabling wider therapeutic windows, improved pharmacokinetic/pharmacodynamic properties, and enhanced efficacy. Since tubulin inhibitors are one of the most successful cytotoxic drugs in the ADC armamentarium, this review focuses on the progress in tubulin inhibitor-based ADCs, as well as lessons learned from the unsuccessful ADCs containing tubulin inhibitors. This review should be helpful to facilitate future development of new generations of tubulin inhibitor-based ADCs for cancer therapy.
Collapse
|
23
|
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.
Collapse
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
| |
Collapse
|
24
|
Vélez M. Dynamic and Active Proteins: Biomolecular Motors in Engineered Nanostructures. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 940:121-141. [DOI: 10.1007/978-3-319-39196-0_6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
|
25
|
Clark JA, Yeaman EJ, Blizzard CA, Chuckowree JA, Dickson TC. A Case for Microtubule Vulnerability in Amyotrophic Lateral Sclerosis: Altered Dynamics During Disease. Front Cell Neurosci 2016; 10:204. [PMID: 27679561 PMCID: PMC5020100 DOI: 10.3389/fncel.2016.00204] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Accepted: 08/15/2016] [Indexed: 12/11/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is an aggressive multifactorial disease converging on a common pathology: the degeneration of motor neurons (MNs), their axons and neuromuscular synapses. This vulnerability and dysfunction of MNs highlights the dependency of these large cells on their intracellular machinery. Neuronal microtubules (MTs) are intracellular structures that facilitate a myriad of vital neuronal functions, including activity dependent axonal transport. In ALS, it is becoming increasingly apparent that MTs are likely to be a critical component of this disease. Not only are disruptions in this intracellular machinery present in the vast majority of seemingly sporadic cases, recent research has revealed that mutation to a microtubule protein, the tubulin isoform TUBA4A, is sufficient to cause a familial, albeit rare, form of disease. In both sporadic and familial disease, studies have provided evidence that microtubule mediated deficits in axonal transport are the tipping point for MN survivability. Axonal transport deficits would lead to abnormal mitochondrial recycling, decreased vesicle and mRNA transport and limited signaling of key survival factors from the neurons peripheral synapses, causing the characteristic peripheral "die back". This disruption to microtubule dependant transport in ALS has been shown to result from alterations in the phenomenon of microtubule dynamic instability: the rapid growth and shrinkage of microtubule polymers. This is accomplished primarily due to aberrant alterations to microtubule associated proteins (MAPs) that regulate microtubule stability. Indeed, the current literature would argue that microtubule stability, particularly alterations in their dynamics, may be the initial driving force behind many familial and sporadic insults in ALS. Pharmacological stabilization of the microtubule network offers an attractive therapeutic strategy in ALS; indeed it has shown promise in many neurological disorders, ALS included. However, the pathophysiological involvement of MTs and their functions is still poorly understood in ALS. Future investigations will hopefully uncover further therapeutic targets that may aid in combating this awful disease.
Collapse
Affiliation(s)
- Jayden A Clark
- Menzies Institute for Medical Research, University of Tasmania Hobart, TAS, Australia
| | - Elise J Yeaman
- Menzies Institute for Medical Research, University of Tasmania Hobart, TAS, Australia
| | - Catherine A Blizzard
- Menzies Institute for Medical Research, University of Tasmania Hobart, TAS, Australia
| | - Jyoti A Chuckowree
- Menzies Institute for Medical Research, University of Tasmania Hobart, TAS, Australia
| | - Tracey C Dickson
- Menzies Institute for Medical Research, University of Tasmania Hobart, TAS, Australia
| |
Collapse
|
26
|
Voelzmann A, Hahn I, Pearce SP, Sánchez-Soriano N, Prokop A. A conceptual view at microtubule plus end dynamics in neuronal axons. Brain Res Bull 2016; 126:226-237. [PMID: 27530065 PMCID: PMC5090033 DOI: 10.1016/j.brainresbull.2016.08.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Revised: 08/08/2016] [Accepted: 08/11/2016] [Indexed: 12/02/2022]
Abstract
Axons are the cable-like protrusions of neurons which wire up the nervous system. Polar bundles of microtubules (MTs) constitute their structural backbones and are highways for life-sustaining transport between proximal cell bodies and distal synapses. Any morphogenetic changes of axons during development, plastic rearrangement, regeneration or degeneration depend on dynamic changes of these MT bundles. A key mechanism for implementing such changes is the coordinated polymerisation and depolymerisation at the plus ends of MTs within these bundles. To gain an understanding of how such regulation can be achieved at the cellular level, we provide here an integrated overview of the extensive knowledge we have about the molecular mechanisms regulating MT de/polymerisation. We first summarise insights gained from work in vitro, then describe the machinery which supplies the essential tubulin building blocks, the protein complexes associating with MT plus ends, and MT shaft-based mechanisms that influence plus end dynamics. We briefly summarise the contribution of MT plus end dynamics to important cellular functions in axons, and conclude by discussing the challenges and potential strategies of integrating the existing molecular knowledge into conceptual understanding at the level of axons.
Collapse
Affiliation(s)
- André Voelzmann
- The University of Manchester, Faculty of Biology, Medicine and Health, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK
| | - Ines Hahn
- The University of Manchester, Faculty of Biology, Medicine and Health, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK
| | - Simon P Pearce
- The University of Manchester, Faculty of Biology, Medicine and Health, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK; The University of Manchester, School of Mathematics, Alan Turing Building, Oxford Road, Manchester M13 9PL, UK
| | - Natalia Sánchez-Soriano
- University of Liverpool, Institute of Translational Medicine, Department of Cellular and Molecular Physiology, Crown Street, Liverpool, L69 3BX, UK
| | - Andreas Prokop
- The University of Manchester, Faculty of Biology, Medicine and Health, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK.
| |
Collapse
|
27
|
Abstract
Life depends on cell proliferation and the accurate segregation of chromosomes, which are mediated by the microtubule (MT)-based mitotic spindle and ∼200 essential MT-associated proteins. Yet, a mechanistic understanding of how the mitotic spindle is assembled and achieves chromosome segregation is still missing. This is mostly due to the density of MTs in the spindle, which presumably precludes their direct observation. Recent insight has been gained into the molecular building plan of the metaphase spindle using bulk and single-molecule measurements combined with computational modeling. MT nucleation was uncovered as a key principle of spindle assembly, and mechanistic details about MT nucleation pathways and their coordination are starting to be revealed. Lastly, advances in studying spindle assembly can be applied to address the molecular mechanisms of how the spindle segregates chromosomes.
Collapse
Affiliation(s)
- Sabine Petry
- Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544-1014;
| |
Collapse
|
28
|
Peters GM, Skala LP, Davis JT. A Molecular Chaperone for G4-Quartet Hydrogels. J Am Chem Soc 2015; 138:134-9. [DOI: 10.1021/jacs.5b08769] [Citation(s) in RCA: 89] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Gretchen Marie Peters
- Department of Chemistry and
Biochemistry, University of Maryland, College Park, Maryland 20742, United States
| | - Luke P. Skala
- Department of Chemistry and
Biochemistry, University of Maryland, College Park, Maryland 20742, United States
| | - Jeffery T. Davis
- Department of Chemistry and
Biochemistry, University of Maryland, College Park, Maryland 20742, United States
| |
Collapse
|
29
|
Abstract
Microtubules are cytoskeletal filaments that are intrinsically polarized, with two structurally and functionally distinct ends, the plus end and the minus end. Over the last decade, numerous studies have shown that microtubule plus-end dynamics play an important role in many vital cellular processes and are controlled by numerous factors, such as microtubule plus-end-tracking proteins (+TIPs). In contrast, the cellular machinery that controls the behavior and organization of microtubule minus ends remains one of the least well-understood facets of the microtubule cytoskeleton. The recent characterization of the CAMSAP/Patronin/Nezha family members as specific 'minus-end-targeting proteins' ('-TIPs') has provided important new insights into the mechanisms governing minus-end dynamics. Here, we review the current state of knowledge on how microtubule minus ends are controlled and how minus-end regulators contribute to non-centrosomal microtubule organization and function during cell division, migration and differentiation.
Collapse
|
30
|
Monroe N, Hill CP. Meiotic Clade AAA ATPases: Protein Polymer Disassembly Machines. J Mol Biol 2015; 428:1897-911. [PMID: 26555750 DOI: 10.1016/j.jmb.2015.11.004] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Revised: 11/03/2015] [Accepted: 11/04/2015] [Indexed: 12/20/2022]
Abstract
Meiotic clade AAA ATPases (ATPases associated with diverse cellular activities), which were initially grouped on the basis of phylogenetic classification of their AAA ATPase cassette, include four relatively well characterized family members, Vps4, spastin, katanin and fidgetin. These enzymes all function to disassemble specific polymeric protein structures, with Vps4 disassembling the ESCRT-III polymers that are central to the many membrane-remodeling activities of the ESCRT (endosomal sorting complexes required for transport) pathway and spastin, katanin p60 and fidgetin affecting multiple aspects of cellular dynamics by severing microtubules. They share a common domain architecture that features an N-terminal MIT (microtubule interacting and trafficking) domain followed by a single AAA ATPase cassette. Meiotic clade AAA ATPases function as hexamers that can cycle between the active assembly and inactive monomers/dimers in a regulated process, and they appear to disassemble their polymeric substrates by translocating subunits through the central pore of their hexameric ring. Recent studies with Vps4 have shown that nucleotide-induced asymmetry is a requirement for substrate binding to the pore loops and that recruitment to the protein lattice via MIT domains also relieves autoinhibition and primes the AAA ATPase cassettes for substrate binding. The most striking, unifying feature of meiotic clade AAA ATPases may be their MIT domain, which is a module that is found in a wide variety of proteins that localize to ESCRT-III polymers. Spastin also displays an adjacent microtubule binding sequence, and the presence of both ESCRT-III and microtubule binding elements may underlie the recent findings that the ESCRT-III disassembly function of Vps4 and the microtubule-severing function of spastin, as well as potentially katanin and fidgetin, are highly coordinated.
Collapse
Affiliation(s)
- Nicole Monroe
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT 84112-5650, USA
| | - Christopher P Hill
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT 84112-5650, USA.
| |
Collapse
|
31
|
Brum AM, van de Peppel J, van der Leije CS, Schreuders-Koedam M, Eijken M, van der Eerden BCJ, van Leeuwen JPTM. Connectivity Map-based discovery of parbendazole reveals targetable human osteogenic pathway. Proc Natl Acad Sci U S A 2015; 112:12711-6. [PMID: 26420877 PMCID: PMC4611615 DOI: 10.1073/pnas.1501597112] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Osteoporosis is a common skeletal disorder characterized by low bone mass leading to increased bone fragility and fracture susceptibility. In this study, we have identified pathways that stimulate differentiation of bone forming osteoblasts from human mesenchymal stromal cells (hMSCs). Gene expression profiling was performed in hMSCs differentiated toward osteoblasts (at 6 h). Significantly regulated genes were analyzed in silico, and the Connectivity Map (CMap) was used to identify candidate bone stimulatory compounds. The signature of parbendazole matches the expression changes observed for osteogenic hMSCs. Parbendazole stimulates osteoblast differentiation as indicated by increased alkaline phosphatase activity, mineralization, and up-regulation of bone marker genes (alkaline phosphatase/ALPL, osteopontin/SPP1, and bone sialoprotein II/IBSP) in a subset of the hMSC population resistant to the apoptotic effects of parbendazole. These osteogenic effects are independent of glucocorticoids because parbendazole does not up-regulate glucocorticoid receptor (GR) target genes and is not inhibited by the GR antagonist mifepristone. Parbendazole causes profound cytoskeletal changes including degradation of microtubules and increased focal adhesions. Stabilization of microtubules by pretreatment with Taxol inhibits osteoblast differentiation. Parbendazole up-regulates bone morphogenetic protein 2 (BMP-2) gene expression and activity. Cotreatment with the BMP-2 antagonist DMH1 limits, but does not block, parbendazole-induced mineralization. Using the CMap we have identified a previously unidentified lineage-specific, bone anabolic compound, parbendazole, which induces osteogenic differentiation through a combination of cytoskeletal changes and increased BMP-2 activity.
Collapse
Affiliation(s)
- Andrea M Brum
- Department of Internal Medicine, Erasmus MC, 3015 CN Rotterdam, The Netherlands
| | | | | | | | | | | | | |
Collapse
|
32
|
Nogales E. An electron microscopy journey in the study of microtubule structure and dynamics. Protein Sci 2015; 24:1912-9. [PMID: 26401895 DOI: 10.1002/pro.2808] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Revised: 09/18/2015] [Accepted: 09/18/2015] [Indexed: 12/30/2022]
Abstract
Structural characterization of microtubules has been the realm of three-dimensional electron microscopy and thus has evolved hand in hand with the progress of this technique, from the initial 3D reconstructions of stained tubulin assemblies, and the first atomic model of tubulin by electron crystallography of 2D sheets of protofilaments, to the ever more detailed cryoelectron microscopy structures of frozen-hydrated microtubules. Most recently, hybrid helical and single particle image processing techniques, and the latest detector technology, have lead to atomic models built directly into the density maps of microtubules in different functional states, shading new light into the critical process of microtubule dynamic instability.
Collapse
Affiliation(s)
- Eva Nogales
- Molecular and Cell Biology Department and QB3 Institute, UC Berkeley, California, 94720.,Howard Hughes Medical Institute, UC Berkeley, California, 94720.,Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, 94720
| |
Collapse
|
33
|
Nogales E, Scheres SHW. Cryo-EM: A Unique Tool for the Visualization of Macromolecular Complexity. Mol Cell 2015; 58:677-89. [PMID: 26000851 DOI: 10.1016/j.molcel.2015.02.019] [Citation(s) in RCA: 232] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
3D cryo-electron microscopy (cryo-EM) is an expanding structural biology technique that has recently undergone a quantum leap progression in its achievable resolution and its applicability to the study of challenging biological systems. Because crystallization is not required, only small amounts of sample are needed, and because images can be classified in a computer, the technique has the potential to deal with compositional and conformational mixtures. Therefore, cryo-EM can be used to investigate complete and fully functional macromolecular complexes in different functional states, providing a richness of biological insight. In this review, we underlie some of the principles behind the cryo-EM methodology of single particle analysis and discuss some recent results of its application to challenging systems of paramount biological importance. We place special emphasis on new methodological developments that are leading to an explosion of new studies, many of which are reaching resolutions that could only be dreamed of just a couple of years ago.
Collapse
Affiliation(s)
- Eva Nogales
- Molecular and Cell Biology Department, UC Berkeley, Berkeley, CA 94720-3220, USA; Howard Hughes Medical Institute, UC Berkeley, Berkeley, CA 94720-3220, USA; Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
| | - Sjors H W Scheres
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK
| |
Collapse
|
34
|
Abstract
Aggregation of the high-affinity IgE receptor (FcεRI) on the plasma membrane of mast cells and basophils initiates signaling events leading to a rapid release of preformed inflammatory mediators from secretory granules, and overall changes in cell morphology. Mast cell activation also causes reorganization of cytoskeletal components associated with membrane ruffling, spreading, and migration. Here we describe methods used for visualization of mast cell cytoskeleton, focusing on its two major components, microfilaments and microtubules, and their changes after cell triggering.
Collapse
|
35
|
Ayoub AT, Klobukowski M, Tuszynski JA. Detailed Per-residue Energetic Analysis Explains the Driving Force for Microtubule Disassembly. PLoS Comput Biol 2015; 11:e1004313. [PMID: 26030285 PMCID: PMC4452272 DOI: 10.1371/journal.pcbi.1004313] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Accepted: 05/05/2015] [Indexed: 11/19/2022] Open
Abstract
Microtubules are long filamentous hollow cylinders whose surfaces form lattice structures of αβ-tubulin heterodimers. They perform multiple physiological roles in eukaryotic cells and are targets for therapeutic interventions. In our study, we carried out all-atom molecular dynamics simulations for arbitrarily long microtubules that have either GDP or GTP molecules in the E-site of β-tubulin. A detailed energy balance of the MM/GBSA inter-dimer interaction energy per residue contributing to the overall lateral and longitudinal structural stability was performed. The obtained results identified the key residues and tubulin domains according to their energetic contributions. They also identified the molecular forces that drive microtubule disassembly. At the tip of the plus end of the microtubule, the uneven distribution of longitudinal interaction energies within a protofilament generates a torque that bends tubulin outwardly with respect to the cylinder's axis causing disassembly. In the presence of GTP, this torque is opposed by lateral interactions that prevent outward curling, thus stabilizing the whole microtubule. Once GTP hydrolysis reaches the tip of the microtubule (lateral cap), lateral interactions become much weaker, allowing tubulin dimers to bend outwards, causing disassembly. The role of magnesium in the process of outward curling has also been demonstrated. This study also showed that the microtubule seam is the most energetically labile inter-dimer interface and could serve as a trigger point for disassembly. Based on a detailed balance of the energetic contributions per amino acid residue in the microtubule, numerous other analyses could be performed to give additional insights into the properties of microtubule dynamic instability.
Collapse
Affiliation(s)
- Ahmed T. Ayoub
- Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada
| | | | - Jack A. Tuszynski
- Department of Oncology, University of Alberta, Edmonton, Alberta, Canada
- Department of Physics, University of Alberta, Edmonton, Alberta, Canada
| |
Collapse
|
36
|
Abstract
The microtubule (MT) cytoskeleton gives cells their shape, organizes the cellular interior, and segregates chromosomes. These functions rely on the precise arrangement of MTs, which is achieved by the coordinated action of MT-associated proteins (MAPs). We highlight the first and most important examples of how different MAP activities are combined in vitro to create an ensemble function that exceeds the simple addition of their individual activities, and how the Xenopus laevis egg extract system has been utilized as a powerful intermediate between cellular and purified systems to uncover the design principles of self-organized MT networks in the cell.
Collapse
Affiliation(s)
- Ray Alfaro-Aco
- From the Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544
| | - Sabine Petry
- From the Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544
| |
Collapse
|
37
|
Negi AS, Gautam Y, Alam S, Chanda D, Luqman S, Sarkar J, Khan F, Konwar R. Natural antitubulin agents: importance of 3,4,5-trimethoxyphenyl fragment. Bioorg Med Chem 2014; 23:373-89. [PMID: 25564377 DOI: 10.1016/j.bmc.2014.12.027] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Revised: 12/11/2014] [Accepted: 12/12/2014] [Indexed: 01/29/2023]
Abstract
Microtubules are polar cytoskeletal filaments assembled from head-to-tail and comprised of lateral associations of α/β-tubulin heterodimers that play key role in various cellular processes. Because of their vital role in mitosis and various other cellular processes, microtubules have been attractive targets for several disease conditions and especially for cancer. Antitubulin is the most successful class of antimitotic agents in cancer chemotherapeutics. The target recognition of antimitotic agents as a ligand is not much explored so far. However, 3,4,5-trimethoxyphenyl fragment has been much highlighted and discussed in such type of interactions. In this review, some of the most important naturally occurring antimitotic agents and their interactions with microtubules are discussed with a special emphasis on the role of 3,4,5-trimethoxyphenyl unit. At last, some emerging naturally occurring antimitotic agents have also been tabulated.
Collapse
Affiliation(s)
- Arvind S Negi
- CSIR-Central Institute of Medicinal and Aromatic Plants (CSIR-CIMAP), Kukrail Picnic Spot Road, PO CIMAP, Lucknow 226015, India.
| | - Yashveer Gautam
- CSIR-Central Institute of Medicinal and Aromatic Plants (CSIR-CIMAP), Kukrail Picnic Spot Road, PO CIMAP, Lucknow 226015, India
| | - Sarfaraz Alam
- CSIR-Central Institute of Medicinal and Aromatic Plants (CSIR-CIMAP), Kukrail Picnic Spot Road, PO CIMAP, Lucknow 226015, India
| | - Debabrata Chanda
- CSIR-Central Institute of Medicinal and Aromatic Plants (CSIR-CIMAP), Kukrail Picnic Spot Road, PO CIMAP, Lucknow 226015, India
| | - Suaib Luqman
- CSIR-Central Institute of Medicinal and Aromatic Plants (CSIR-CIMAP), Kukrail Picnic Spot Road, PO CIMAP, Lucknow 226015, India
| | - Jayanta Sarkar
- CSIR-Central Drug Research Institute (CSIR-CDRI), B.S. 10/1, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow 226031, India
| | - Feroz Khan
- CSIR-Central Institute of Medicinal and Aromatic Plants (CSIR-CIMAP), Kukrail Picnic Spot Road, PO CIMAP, Lucknow 226015, India
| | - Rituraj Konwar
- CSIR-Central Drug Research Institute (CSIR-CDRI), B.S. 10/1, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow 226031, India
| |
Collapse
|
38
|
McMicken B, Thomas RJ, Brancaleon L. Photoinduced partial unfolding of tubulin bound to meso-tetrakis(sulfonatophenyl) porphyrin leads to inhibition of microtubule formation in vitro. JOURNAL OF BIOPHOTONICS 2014; 7:874-888. [PMID: 23893937 DOI: 10.1002/jbio.201300066] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Revised: 06/04/2013] [Accepted: 06/19/2013] [Indexed: 06/02/2023]
Abstract
The irradiation of the complex formed by meso-tetrakis (sulfonatophenyl) porphyrin (TSPP) and tubulin was investigated as well as its effects on the structure and function of the protein. We have used tubulin as a model target to investigate whether photoactive ligands docked to the protein can affect the structure and function of the protein upon exposure to visible light. We observed that laser irradiation prompts bleaching of the porphyrin which is accompanied by a sharp decrease (∼2 ns) in the average fluorescence lifetime of the protein and a change in the dichroic spectrum consistent with a decrease of helical structure. The result indicated the photoinduced partial unfolding of tubulin. We also observed that such partial conformational change inhibits the formation of microtubules in vitro. We investigated whether photosensitization of reactive oxygen species was responsible for these effects. Even upon removal of O2 the protein still undergoes conformational changes indicating that irradiation of the bound porphyrin does not require the presence of O2 to prompt conformational and functional effects opening the possibility that other mechanisms (e.g., charge transfer) are responsible for the photoinduced mechanism.
Collapse
Affiliation(s)
- Brady McMicken
- The University of Texas at San Antonio, Department of Physics and Astronomy, One UTSA Circle, San Antonio, Texas, 78249 USA; Optical Radiation Bioeffects Branch, Bioeffects Division, Air Force Research Laboratory, Fort Sam Houston, Texas 78234, USA
| | | | | |
Collapse
|
39
|
Chiodini G, Pallavicini M, Zanotto C, Bissa M, Radaelli A, Straniero V, Bolchi C, Fumagalli L, Ruggeri P, De Giuli Morghen C, Valoti E. Benzodioxane-benzamides as new bacterial cell division inhibitors. Eur J Med Chem 2014; 89:252-65. [PMID: 25462242 DOI: 10.1016/j.ejmech.2014.09.100] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2014] [Revised: 09/09/2014] [Accepted: 09/15/2014] [Indexed: 11/30/2022]
Abstract
A SAR study was performed on 3-substituted 2,6-difluorobenzamides, known inhibitors of the essential bacterial cell division protein FtsZ, through a series of modifications first of 2,6-difluoro-3-nonyloxybenzamide and then of its 3-pyridothiazolylmethoxy analogue PC190723. The study led to the identification of chiral 2,6-difluorobenzamides bearing 1,4-benzodioxane-2-methyl residue at the 3-position as potent antistaphylococcal compounds.
Collapse
Affiliation(s)
- Giuseppe Chiodini
- Dipartimento di Scienze Farmaceutiche, Università di Milano, Via Mangiagalli 25, I-20133 Milano, Italy
| | - Marco Pallavicini
- Dipartimento di Scienze Farmaceutiche, Università di Milano, Via Mangiagalli 25, I-20133 Milano, Italy
| | - Carlo Zanotto
- Department of Medical Biothechnologies and Translational Medicine, Università di Milano, Via Vanvitelli 32, I-20129 Milano, Italy
| | - Massimiliano Bissa
- Department of Pharmacological and Biomolecular Sciences, Università di Milano, Via Balzaretti 9, I-2013 Milano, Italy
| | - Antonia Radaelli
- Department of Pharmacological and Biomolecular Sciences, Università di Milano, Via Balzaretti 9, I-2013 Milano, Italy; CNR Institute of Neurosciences, Cellular and Molecular Pharmacology Section, Università di Milano, Via Vanvitelli 32, I-20129 Milano, Italy
| | - Valentina Straniero
- Dipartimento di Scienze Farmaceutiche, Università di Milano, Via Mangiagalli 25, I-20133 Milano, Italy
| | - Cristiano Bolchi
- Dipartimento di Scienze Farmaceutiche, Università di Milano, Via Mangiagalli 25, I-20133 Milano, Italy
| | - Laura Fumagalli
- Dipartimento di Scienze Farmaceutiche, Università di Milano, Via Mangiagalli 25, I-20133 Milano, Italy
| | - Paola Ruggeri
- Dipartimento di Scienze Farmaceutiche, Università di Milano, Via Mangiagalli 25, I-20133 Milano, Italy
| | - Carlo De Giuli Morghen
- Department of Medical Biothechnologies and Translational Medicine, Università di Milano, Via Vanvitelli 32, I-20129 Milano, Italy; CNR Institute of Neurosciences, Cellular and Molecular Pharmacology Section, Università di Milano, Via Vanvitelli 32, I-20129 Milano, Italy
| | - Ermanno Valoti
- Dipartimento di Scienze Farmaceutiche, Università di Milano, Via Mangiagalli 25, I-20133 Milano, Italy.
| |
Collapse
|
40
|
Biophysical highlights from 54 years of macromolecular crystallography. Biophys J 2014; 106:510-25. [PMID: 24507592 DOI: 10.1016/j.bpj.2014.01.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2013] [Accepted: 01/03/2014] [Indexed: 12/22/2022] Open
Abstract
The United Nations has declared 2014 the International Year of Crystallography, and in commemoration, this review features a selection of 54 notable macromolecular crystal structures that have illuminated the field of biophysics in the 54 years since the first excitement of the myoglobin and hemoglobin structures in 1960. Chronological by publication of the earliest solved structure, each illustrated entry briefly describes key concepts or methods new at the time and key later work leveraged by knowledge of the three-dimensional atomic structure.
Collapse
|
41
|
Alushin GM, Lander GC, Kellogg EH, Zhang R, Baker D, Nogales E. High-resolution microtubule structures reveal the structural transitions in αβ-tubulin upon GTP hydrolysis. Cell 2014; 157:1117-29. [PMID: 24855948 DOI: 10.1016/j.cell.2014.03.053] [Citation(s) in RCA: 454] [Impact Index Per Article: 45.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Revised: 01/17/2014] [Accepted: 03/18/2014] [Indexed: 11/26/2022]
Abstract
Dynamic instability, the stochastic switching between growth and shrinkage, is essential for microtubule function. This behavior is driven by GTP hydrolysis in the microtubule lattice and is inhibited by anticancer agents like Taxol. We provide insight into the mechanism of dynamic instability, based on high-resolution cryo-EM structures (4.7-5.6 Å) of dynamic microtubules and microtubules stabilized by GMPCPP or Taxol. We infer that hydrolysis leads to a compaction around the E-site nucleotide at longitudinal interfaces, as well as movement of the α-tubulin intermediate domain and H7 helix. Displacement of the C-terminal helices in both α- and β-tubulin subunits suggests an effect on interactions with binding partners that contact this region. Taxol inhibits most of these conformational changes, allosterically inducing a GMPCPP-like state. Lateral interactions are similar in all conditions we examined, suggesting that microtubule lattice stability is primarily modulated at longitudinal interfaces.
Collapse
Affiliation(s)
- Gregory M Alushin
- Biophysics Graduate Program, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Gabriel C Lander
- Life Sciences Division, Lawrence Berkeley National Lab, Berkeley, CA 94720, USA
| | - Elizabeth H Kellogg
- Howard Hughes Medical Institute, Department of Biochemistry, University of Washington, Seattle, WA 98105, USA
| | - Rui Zhang
- Life Sciences Division, Lawrence Berkeley National Lab, Berkeley, CA 94720, USA
| | - David Baker
- Howard Hughes Medical Institute, Department of Biochemistry, University of Washington, Seattle, WA 98105, USA
| | - Eva Nogales
- Life Sciences Division, Lawrence Berkeley National Lab, Berkeley, CA 94720, USA; Howard Hughes Medical Institute, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA.
| |
Collapse
|
42
|
Abstract
We introduce a model for microtubule (MT) mechanics containing lateral bonds between dimers in neighboring protofilaments, bending rigidity of dimers, and repulsive interactions between protofilaments modeling steric constraints to investigate the influence of mechanical forces on hydrolysis and catastrophes. We use the allosteric dimer model, where tubulin dimers are characterized by an equilibrium bending angle, which changes from 0° to 22° by hydrolysis of a dimer. This also affects the lateral interaction and bending energies and, thus, the mechanical equilibrium state of the MT. As hydrolysis gives rise to conformational changes in dimers, mechanical forces also influence the hydrolysis rates by mechanical energy changes modulating the hydrolysis rate. The interaction via the MT mechanics then gives rise to correlation effects in the hydrolysis dynamics, which have not been taken into account before. Assuming a dominant influence of mechanical energies on hydrolysis rates, we investigate the most probable hydrolysis pathways both for vectorial and random hydrolysis. Investigating the stability with respect to lateral bond rupture, we identify initiation configurations for catastrophes along the hydrolysis pathways and values for a lateral bond rupture force. If we allow for rupturing of lateral bonds between dimers in neighboring protofilaments above this threshold force, our model exhibits avalanche-like catastrophe events.
Collapse
Affiliation(s)
- N Müller
- Department of Physics, TU Dortmund University, D-44221 Dortmund, Germany
| | | |
Collapse
|
43
|
Paños J, Díaz-Oltra S, Sánchez-Peris M, García-Pla J, Murga J, Falomir E, Carda M, Redondo-Horcajo M, Díaz JF, Barasoain I, Marco JA. Synthesis and biological evaluation of truncated α-tubulin-binding pironetin analogues lacking alkyl pendants in the side chain or the dihydropyrone ring. Org Biomol Chem 2014; 11:5809-26. [PMID: 23892508 DOI: 10.1039/c3ob40854j] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The preparation of several new truncated analogues of the natural dihydropyrone pironetin is described. They differ from the natural product mainly in the suppression of some of the alkyl pendants in either the side chain or the dihydropyrone ring. Their cytotoxic activity and their interactions with tubulin have been investigated. It has been found that all analogues are cytotoxic towards two either sensitive or resistant tumoral cell lines with similar IC50 values in each case, thus strongly suggesting that, like natural pironetin, they also display a covalent mechanism of action. Their cytotoxicity is, however, lower than that of the parent compound. This indicates that all alkyl pendants are necessary for the full biological activity, with the ethyl group at C-4 seemingly being particularly relevant. Most likely, the alkyl groups cause a restriction in the conformational mobility of the molecule and reduce the number of available conformations. This makes it more probable that the molecule preferentially adopts a shape which fits better into the binding point in α-tubulin.
Collapse
Affiliation(s)
- Julián Paños
- Depart. de Q. Inorgánica y Orgánica, Univ. Jaume I, Castellón, E-12071 Castellón, Spain.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
44
|
Gornstein E, Schwarz TL. The paradox of paclitaxel neurotoxicity: Mechanisms and unanswered questions. Neuropharmacology 2014; 76 Pt A:175-83. [DOI: 10.1016/j.neuropharm.2013.08.016] [Citation(s) in RCA: 143] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Revised: 07/26/2013] [Accepted: 08/07/2013] [Indexed: 11/17/2022]
|
45
|
Horio T, Murata T. The role of dynamic instability in microtubule organization. FRONTIERS IN PLANT SCIENCE 2014; 5:511. [PMID: 25339962 PMCID: PMC4188131 DOI: 10.3389/fpls.2014.00511] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 09/12/2014] [Indexed: 05/09/2023]
Abstract
Microtubules are one of the three major cytoskeletal components in eukaryotic cells. Heterodimers composed of GTP-bound α- and β-tubulin molecules polymerize to form microtubule protofilaments, which associate laterally to form a hollow microtubule. Tubulin has GTPase activity and the GTP molecules associated with β-tubulin molecules are hydrolyzed shortly after being incorporated into the polymerizing microtubules. GTP hydrolysis alters the conformation of the tubulin molecules and drives the dynamic behavior of microtubules. Periods of rapid microtubule polymerization alternate with periods of shrinkage in a process known as dynamic instability. In plants, dynamic instability plays a key role in determining the organization of microtubules into arrays, and these arrays vary throughout the cell cycle. In this review, we describe the mechanisms that regulate microtubule dynamics and underlie dynamic instability, and discuss how dynamic instability may shape microtubule organization in plant cells.
Collapse
Affiliation(s)
- Tetsuya Horio
- Department of Natural Sciences, Nippon Sport Science UniversityYokohama, Japan
| | - Takashi Murata
- Division of Evolutionary Biology, National Institute for Basic BiologyOkazaki, Japan
- Department of Basic Biology, School of Life Sciences, The Graduate University for Advanced StudiesOkazaki, Japan
- *Correspondence: Takashi Murata, Division of Evolutionary Biology, National Institute for Basic Biology, Myodaiji, Okazaki, Aichi 444-8585, Japan e-mail:
| |
Collapse
|
46
|
Webber MJ, Berns EJ, Stupp SI. Supramolecular Nanofibers of Peptide Amphiphiles for Medicine. Isr J Chem 2013; 53:530-554. [PMID: 24532851 PMCID: PMC3922220 DOI: 10.1002/ijch.201300046] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Peptide nanostructures are an exciting class of supramolecular systems that can be designed for novel therapies with great potential in advanced medicine. This paper reviews progress on nanostructures based on peptide amphiphiles capable of forming one-dimensional assemblies that emulate in structure the nanofibers present in extracellular matrices. These systems are highly tunable using supramolecular chemistry, and can be designed to signal cells directly with bioactive peptides. Peptide amphiphile nanofibers can also be used to multiplex functions through co-assembly and designed to deliver proteins, nucleic acids, drugs, or cells. We illustrate here the functionality of these systems describing their use in regenerative medicine of bone, cartilage, the nervous system, the cardiovascular system, and other tissues. In addition, we highlight recent work on the use of peptide amphiphile assemblies to create hierarchical biomimetic structures with order beyond the nanoscale, and also discuss the future prospects of these supramolecular systems.
Collapse
Affiliation(s)
- Matthew J. Webber
- Northwestern University Department of Biomedical Engineering, Evanston, Illinois, 60208 USA
- Institute for Bionanotechnology in Medicine, Northwestern University Chicago, Illinois, 60611 USA
| | - Eric J. Berns
- Northwestern University Department of Biomedical Engineering, Evanston, Illinois, 60208 USA
- Institute for Bionanotechnology in Medicine, Northwestern University Chicago, Illinois, 60611 USA
| | - Samuel I. Stupp
- Institute for Bionanotechnology in Medicine, Northwestern University Chicago, Illinois, 60611 USA
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois, 60208 USA
- Department of Chemistry, Northwestern University, Evanston, Illinois, 60208 USA
- Department of Medicine, Northwestern University, Chicago, Illinois, 60611 USA
| |
Collapse
|
47
|
Coombes CE, Yamamoto A, Kenzie MR, Odde DJ, Gardner MK. Evolving tip structures can explain age-dependent microtubule catastrophe. Curr Biol 2013; 23:1342-8. [PMID: 23831290 DOI: 10.1016/j.cub.2013.05.059] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2012] [Revised: 05/22/2013] [Accepted: 05/30/2013] [Indexed: 11/27/2022]
Abstract
Microtubules are key structural and transport elements in cells. The dynamics at microtubule ends are characterized by periods of slow growth, followed by stochastic switching events termed "catastrophes," in which microtubules suddenly undergo rapid shortening. Growing microtubules are thought to be protected from catastrophe by a GTP-tubulin "cap": GTP-tubulin subunits add to the tips of growing microtubules but are subsequently hydrolyzed to GDP-tubulin subunits once they are incorporated into the microtubule lattice. Loss of the GTP-tubulin cap exposes GDP-tubulin subunits at the microtubule tip, resulting in a catastrophe event. However, the mechanistic basis for sudden loss of the GTP cap, leading to catastrophe, is not known. To investigate microtubule catastrophe events, we performed 3D mechanochemical simulations that account for interactions between neighboring protofilaments. We found that there are two separate factors that contribute to catastrophe events in the 3D simulation: the GTP-tubulin cap size, which settles into a steady-state value that depends on the free tubulin concentration during microtubule growth, and the structure of the microtubule tip. Importantly, 3D simulations predict, and both fluorescence and electron microscopy experiments confirm, that microtubule tips become more tapered as the microtubule grows. This effect destabilizes the tip and ultimately contributes to microtubule catastrophe. Thus, the likelihood of a catastrophe event may be intimately linked to the aging physical structure of the growing microtubule tip. These results have important consequences for catastrophe regulation in cells, as microtubule-associated proteins could promote catastrophe events in part by modifying microtubule tip structures.
Collapse
Affiliation(s)
- Courtney E Coombes
- Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN 55455, USA
| | | | | | | | | |
Collapse
|
48
|
Comolli LR, Siegerist CE, Shin SH, Bertozzi C, Regan W, Zettl A, De Yoreo J. Conformational Transitions at an S-Layer Growing Boundary Resolved by Cryo-TEM. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201300543] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
|
49
|
Quiniou E, Guichard P, Perahia D, Marco S, Mouawad L. An atomistic view of microtubule stabilization by GTP. Structure 2013; 21:833-43. [PMID: 23623730 DOI: 10.1016/j.str.2013.03.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2012] [Revised: 02/08/2013] [Accepted: 03/08/2013] [Indexed: 11/27/2022]
Abstract
A microtubule is a dynamic system formed of αβ-tubulins. The presence of nonhydrolyzable guanosine-5'-triphosphate (GTP)/guanosine diphosphate (GDP) on the β-tubulins provokes microtubule polymerization/depolymerization. Despite the large number of experimental studies of this dynamical process, its mechanism is still unclear. To provide insights into this mechanism we studied the first depolymerization steps of GDP/GTP-bound microtubules by normal-mode analysis with the all-atom model. We also constructed a depolymerizing microtubule and compared it to cryo-electron microscopy tomograms (cyro-ET). The results show that during depolymerization, the protofilaments not only curve but twist to weaken their lateral interactions. These interactions are stabilized by GTP, but not evenly. Not all of the interface residues are of equal importance: five of them, belonging to the H2-S3 loop, play a special role; acting as a lock whose key is the γ-phosphate of GTP. Sequence alignments of several tubulins confirm the importance of these residues.
Collapse
Affiliation(s)
- Eric Quiniou
- Institut Curie, Centre de Recherche, U759, Bât. 112, Centre Universitaire, 91405 Orsay Cedex, France
| | | | | | | | | |
Collapse
|
50
|
Rago F, Cheeseman IM. Review series: The functions and consequences of force at kinetochores. ACTA ACUST UNITED AC 2013; 200:557-65. [PMID: 23460675 PMCID: PMC3587826 DOI: 10.1083/jcb.201211113] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Chromosome segregation requires the generation of force at the kinetochore—the multiprotein structure that facilitates attachment of chromosomes to spindle microtubules. This force is required both to move chromosomes and to signal the formation of proper bioriented attachments. To understand the role of force in these processes, it is critical to define how force is generated at kinetochores, the contributions of this force to chromosome movement, and how the kinetochore is structured and organized to withstand and respond to force. Classical studies and recent work provide a framework to dissect the mechanisms, functions, and consequences of force at kinetochores.
Collapse
Affiliation(s)
- Florencia Rago
- Whitehead Institute for Biomedical Research, Massachusetts Institute of Technology, Cambridge, MA 0214, USA
| | | |
Collapse
|