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Breuss MW, Nguyen T, Srivatsan A, Leca I, Tian G, Fritz T, Hansen AH, Musaev D, McEvoy-Venneri J, James KN, Rosti RO, Scott E, Tan U, Kolodner RD, Cowan NJ, Keays DA, Gleeson JG. Uner Tan syndrome caused by a homozygous TUBB2B mutation affecting microtubule stability. Hum Mol Genet 2017; 26:258-269. [PMID: 28013290 DOI: 10.1093/hmg/ddw383] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Accepted: 11/03/2016] [Indexed: 01/07/2023] Open
Abstract
The integrity and dynamic properties of the microtubule cytoskeleton are indispensable for the development of the mammalian brain. Consequently, mutations in the genes that encode the structural component (the α/β-tubulin heterodimer) can give rise to severe, sporadic neurodevelopmental disorders. These are commonly referred to as the tubulinopathies. Here we report the addition of recessive quadrupedalism, also known as Uner Tan syndrome (UTS), to the growing list of diseases caused by tubulin variants. Analysis of a consanguineous UTS family identified a biallelic TUBB2B mutation, resulting in a p.R390Q amino acid substitution. In addition to the identifying quadrupedal locomotion, all three patients showed severe cerebellar hypoplasia. None, however, displayed the basal ganglia malformations typically associated with TUBB2B mutations. Functional analysis of the R390Q substitution revealed that it did not affect the ability of β-tubulin to fold or become assembled into the α/β-heterodimer, nor did it influence the incorporation of mutant-containing heterodimers into microtubule polymers. The 390Q mutation in S. cerevisiae TUB2 did not affect growth under basal conditions, but did result in increased sensitivity to microtubule-depolymerizing drugs, indicative of a mild impact of this mutation on microtubule function. The TUBB2B mutation described here represents an unusual recessive mode of inheritance for missense-mediated tubulinopathies and reinforces the sensitivity of the developing cerebellum to microtubule defects.
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Affiliation(s)
- Martin W Breuss
- Department of Neurosciences, Howard Hughes Medical Institute, University of California, San Diego, La Jolla, CA, USA.,Rady Children's Institute for Genomic Medicine, San Diego, CA, USA
| | - Thai Nguyen
- Department of Neurosciences, Howard Hughes Medical Institute, University of California, San Diego, La Jolla, CA, USA.,Rady Children's Institute for Genomic Medicine, San Diego, CA, USA
| | - Anjana Srivatsan
- Ludwig Institute for Cancer Research, University of California School of Medicine, San Diego, La Jolla, CA, USA
| | - Ines Leca
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria
| | - Guoling Tian
- Department of Biochemistry and Molecular Pharmacology, New York University Langone Medical Center, New York, NY, USA
| | - Tanja Fritz
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria
| | - Andi H Hansen
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria
| | - Damir Musaev
- Department of Neurosciences, Howard Hughes Medical Institute, University of California, San Diego, La Jolla, CA, USA.,Rady Children's Institute for Genomic Medicine, San Diego, CA, USA
| | - Jennifer McEvoy-Venneri
- Department of Neurosciences, Howard Hughes Medical Institute, University of California, San Diego, La Jolla, CA, USA.,Rady Children's Institute for Genomic Medicine, San Diego, CA, USA
| | - Kiely N James
- Department of Neurosciences, Howard Hughes Medical Institute, University of California, San Diego, La Jolla, CA, USA.,Rady Children's Institute for Genomic Medicine, San Diego, CA, USA
| | - Rasim O Rosti
- Department of Neurosciences, Howard Hughes Medical Institute, University of California, San Diego, La Jolla, CA, USA.,Rady Children's Institute for Genomic Medicine, San Diego, CA, USA
| | - Eric Scott
- Department of Neurosciences, Howard Hughes Medical Institute, University of California, San Diego, La Jolla, CA, USA.,Rady Children's Institute for Genomic Medicine, San Diego, CA, USA
| | - Uner Tan
- Department of Physiology, Medical School, Cukurova University, Adana, Turkey and
| | - Richard D Kolodner
- Ludwig Institute for Cancer Research, University of California School of Medicine, San Diego, La Jolla, CA, USA.,Department of Cellular and Molecular Medicine, Institute for Genomic Medicine and Moores-UCSD Cancer Center, San Diego, La Jolla, CA, USA
| | - Nicholas J Cowan
- Department of Biochemistry and Molecular Pharmacology, New York University Langone Medical Center, New York, NY, USA
| | - David A Keays
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria
| | - Joseph G Gleeson
- Department of Neurosciences, Howard Hughes Medical Institute, University of California, San Diego, La Jolla, CA, USA.,Rady Children's Institute for Genomic Medicine, San Diego, CA, USA
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2
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Driver JW, Geyer EA, Bailey ME, Rice LM, Asbury CL. Direct measurement of conformational strain energy in protofilaments curling outward from disassembling microtubule tips. eLife 2017. [PMID: 28628007 PMCID: PMC5515574 DOI: 10.7554/elife.28433] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Disassembling microtubules can generate movement independently of motor enzymes, especially at kinetochores where they drive chromosome motility. A popular explanation is the 'conformational wave' model, in which protofilaments pull on the kinetochore as they curl outward from a disassembling tip. But whether protofilaments can work efficiently via this spring-like mechanism has been unclear. By modifying a previous assay to use recombinant tubulin and feedback-controlled laser trapping, we directly demonstrate the spring-like elasticity of curling protofilaments. Measuring their mechanical work output suggests they carry ~25% of the energy of GTP hydrolysis as bending strain, enabling them to drive movement with efficiency similar to conventional motors. Surprisingly, a β-tubulin mutant that dramatically slows disassembly has no effect on work output, indicating an uncoupling of disassembly speed from protofilament strain. These results show the wave mechanism can make a major contribution to kinetochore motility and establish a direct approach for measuring tubulin mechano-chemistry.
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Affiliation(s)
- Jonathan W Driver
- Department of Physiology and Biophysics, University of Washington, Seattle, United States
| | - Elisabeth A Geyer
- Department of Biophysics, UT Southwestern Medical Center, Dallas, United States.,Department of Biochemistry, UT Southwestern Medical Center, Dallas, United States
| | - Megan E Bailey
- Department of Physiology and Biophysics, University of Washington, Seattle, United States
| | - Luke M Rice
- Department of Biophysics, UT Southwestern Medical Center, Dallas, United States.,Department of Biochemistry, UT Southwestern Medical Center, Dallas, United States
| | - Charles L Asbury
- Department of Physiology and Biophysics, University of Washington, Seattle, United States
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3
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Minoura I. Towards an understanding of the isotype-specific functions of tubulin in neurons: Technical advances in tubulin expression and purification. Neurosci Res 2017; 122:1-8. [PMID: 28412269 DOI: 10.1016/j.neures.2017.04.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Revised: 03/29/2017] [Accepted: 04/07/2017] [Indexed: 12/20/2022]
Abstract
Microtubules are cytoskeletal filaments critical for determining the complex morphology of neurons, as well as the basic architecture and organization of mitosis in all eukaryotic cells. Microtubules in humans are composed of 8 α- and 9 β-tubulin isotypes, each of which is encoded by different members of a multi-gene family. The expression pattern of tubulin isotypes, in addition to isotype-specific post-translational modifications, is thought to be critical for the morphogenesis of axons and dendrites. Recent studies revealed that several neurodevelopmental disorders are caused by mutations of specific tubulin isotypes, suggesting that each tubulin isotype has distinct functions. Therefore, in vitro and in vivo functional analyses of tubulin isotypes are important to understand the pathogenesis of developmental disorders. Likewise, analysis of developmental disorders may clarify the function of different tubulin isotypes. In this respect, both the preparation of specific tubulin isotypes and of specific mutant tubulin proteins is critical to understanding the function of tubulin. In the last 20 years, various methods have been developed to study functional differences between tubulin isotypes and the functional defects caused by tubulin mutations. These technical achievements have been discussed in this review. The function of tubulin/microtubules in neuronal morphogenesis as revealed through these techniques has also been described.
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Affiliation(s)
- Itsushi Minoura
- Laboratory for Molecular Biophysics, Brain Science Institute, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan; Goryo Chemical Inc., Earee Bldg. 5F, Kita 8 Nishi 18-35-100, Chuo-ku, Sapporo 060-0008, Japan.
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4
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Piedra FA, Kim T, Garza ES, Geyer EA, Burns A, Ye X, Rice LM. GDP-to-GTP exchange on the microtubule end can contribute to the frequency of catastrophe. Mol Biol Cell 2016; 27:3515-3525. [PMID: 27146111 PMCID: PMC5221584 DOI: 10.1091/mbc.e16-03-0199] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2016] [Accepted: 04/26/2016] [Indexed: 11/11/2022] Open
Abstract
Microtubules are dynamic polymers of αβ-tubulin that have essential roles in chromosome segregation and organization of the cytoplasm. Catastrophe-the switch from growing to shrinking-occurs when a microtubule loses its stabilizing GTP cap. Recent evidence indicates that the nucleotide on the microtubule end controls how tightly an incoming subunit will be bound (trans-acting GTP), but most current models do not incorporate this information. We implemented trans-acting GTP into a computational model for microtubule dynamics. In simulations, growing microtubules often exposed terminal GDP-bound subunits without undergoing catastrophe. Transient GDP exposure on the growing plus end slowed elongation by reducing the number of favorable binding sites on the microtubule end. Slower elongation led to erosion of the GTP cap and an increase in the frequency of catastrophe. Allowing GDP-to-GTP exchange on terminal subunits in simulations mitigated these effects. Using mutant αβ-tubulin or modified GTP, we showed experimentally that a more readily exchangeable nucleotide led to less frequent catastrophe. Current models for microtubule dynamics do not account for GDP-to-GTP exchange on the growing microtubule end, so our findings provide a new way of thinking about the molecular events that initiate catastrophe.
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Affiliation(s)
- Felipe-Andrés Piedra
- Departments of Biophysics and Biochemistry, UT Southwestern Medical Center, Dallas, TX 75390
| | - Tae Kim
- Departments of Biophysics and Biochemistry, UT Southwestern Medical Center, Dallas, TX 75390
| | - Emily S Garza
- Departments of Biophysics and Biochemistry, UT Southwestern Medical Center, Dallas, TX 75390
| | - Elisabeth A Geyer
- Departments of Biophysics and Biochemistry, UT Southwestern Medical Center, Dallas, TX 75390
| | - Alexander Burns
- Departments of Biophysics and Biochemistry, UT Southwestern Medical Center, Dallas, TX 75390
| | - Xuecheng Ye
- Departments of Biophysics and Biochemistry, UT Southwestern Medical Center, Dallas, TX 75390
| | - Luke M Rice
- Departments of Biophysics and Biochemistry, UT Southwestern Medical Center, Dallas, TX 75390
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5
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Geyer EA, Burns A, Lalonde BA, Ye X, Piedra FA, Huffaker TC, Rice LM. A mutation uncouples the tubulin conformational and GTPase cycles, revealing allosteric control of microtubule dynamics. eLife 2015; 4:e10113. [PMID: 26439009 PMCID: PMC4728127 DOI: 10.7554/elife.10113] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Accepted: 10/06/2015] [Indexed: 11/18/2022] Open
Abstract
Microtubule dynamic instability depends on the GTPase activity of the polymerizing αβ-tubulin subunits, which cycle through at least three distinct conformations as they move into and out of microtubules. How this conformational cycle contributes to microtubule growing, shrinking, and switching remains unknown. Here, we report that a buried mutation in αβ-tubulin yields microtubules with dramatically reduced shrinking rate and catastrophe frequency. The mutation causes these effects by suppressing a conformational change that normally occurs in response to GTP hydrolysis in the lattice, without detectably changing the conformation of unpolymerized αβ-tubulin. Thus, the mutation weakens the coupling between the conformational and GTPase cycles of αβ-tubulin. By showing that the mutation predominantly affects post-GTPase conformational and dynamic properties of microtubules, our data reveal that the strength of the allosteric response to GDP in the lattice dictates the frequency of catastrophe and the severity of rapid shrinking. DOI:http://dx.doi.org/10.7554/eLife.10113.001 Protein filaments called microtubules help move cargo around inside cells. Chromosomes, which contain the cell’s genetic blueprints, are the microtubule’s most precious cargo. Before a cell divides, microtubules grow from the ends of the dividing cell towards the middle, where they attach to the chromosomes that are lined up along the centerline. Then the microtubules shrink and drag the chromosomes back to the opposite ends of the cell. This allows each of the new cells to get one copy of each chromosome. When the microtubules are growing, a molecule called guanosine triphosphate (or GTP) is attached to the proteins at the end of the filament. This acts like a cap and protects the microtubule from shrinking. Later a chemical reaction converts GTP into GDP (short for guanosine diphosphate). Without the protective GTP cap, the microtubule quickly shrinks. At the same time, the proteins that make up the microtubule also change shape. In the microtubule, the proteins adopt a straight shape when GTP is attached. The proteins favor a different shape in the microtubule when GDP is attached. However, it is unclear if or how these shape changes contribute to how a microtubule grows or shrinks. Geyer et al. now show how this shape shifting can influence microtubule shrinking, by first identifying a mutation in yeast microtubule proteins that cause the proteins to remain straight even when GDP is attached. Next, powerful microscopes were used to make time-lapse videos of the mutated microtubules. This allowed Geyer et al. to observe how the mutated microtubules behaved and compare this to the behavior of normal microtubules. The experiments revealed that the mutated microtubules were less likely to begin shrinking than typical microtubules. The mutated microtubules also shrunk more slowly. These findings indicate that the shape changes control the speed of shrinking and frequency of entering the shrinking phase. These new details about the control of microtubule growth and shrinkage may help scientists studying how cell division happens in both healthy and cancerous cells. DOI:http://dx.doi.org/10.7554/eLife.10113.002
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Affiliation(s)
- Elisabeth A Geyer
- Departments of Biophysics and Biochemistry, University of Texas Southwestern Medical Center, Dallas, United States
| | - Alexander Burns
- Departments of Biophysics and Biochemistry, University of Texas Southwestern Medical Center, Dallas, United States
| | - Beth A Lalonde
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, United States
| | - Xuecheng Ye
- Departments of Biophysics and Biochemistry, University of Texas Southwestern Medical Center, Dallas, United States
| | - Felipe-Andres Piedra
- Departments of Biophysics and Biochemistry, University of Texas Southwestern Medical Center, Dallas, United States
| | - Tim C Huffaker
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, United States
| | - Luke M Rice
- Departments of Biophysics and Biochemistry, University of Texas Southwestern Medical Center, Dallas, United States
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6
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Chapman MA. Interactions between cell adhesion and the synaptic vesicle cycle in Parkinson's disease. Med Hypotheses 2014; 83:203-7. [PMID: 24837686 DOI: 10.1016/j.mehy.2014.04.029] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Accepted: 04/21/2014] [Indexed: 12/27/2022]
Abstract
Synaptic dysfunction has been identified as an early neuropathologic event in Parkinson's disease. Synapses depend critically on the adhesion of neurons to one another, glial cells, and the extracellular matrix. Cell-cell and cell-matrix adhesions regulate the structure and function of synapses, in part, through interactions with structural elements such as actin and microtubule proteins. These proteins are critical not only for neuronal structure and polarity, but also for the synaptic vesicle cycle, including maintenance of and transfer between vesicle pools, exocytosis, and vesicle recycling. Pathway analyses of genome wide association studies (GWAS) in Parkinson's disease have identified frequent single nucleotide polymorphisms (SNPs) in cell adhesion pathways, suggesting that dysfunction in cell adhesion may play a role in disease pathology. Based on these observations, it may be hypothesized that Parkinson's disease is due to synaptic dysfunction caused by genetic variations in cell adhesion pathways that affect actin and/or microtubule-mediated events in the synaptic vesicle cycle. Furthermore, it is hypothesized that cells with pacemaker-like activity-a characteristic of neurons that degenerate in Parkinson's disease-may depend more on actin for recruiting synaptic vesicles for release than do less active neurons, thereby enhancing their sensitivity to SNPs in cell adhesion pathways and explaining the selectivity of neurodegeneration. Cells may ultimately die due to detachment from the extracellular matrix. This hypothesis suggests that further exploration of cell adhesion pathways and their linkage to neurotransmitter release through cell structural proteins such as actin and microtubules may provide important insights into Parkinson's disease.
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7
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Abstract
Microtubules play essential roles in a wide variety of cellular processes including cell division, motility, and vesicular transport. Microtubule function depends on the polymerization dynamics of tubulin and specific interactions between tubulin and diverse microtubule-associated proteins. To date, investigation of the structural and functional properties of tubulin and tubulin mutants has been limited by the inability to obtain functional protein from overexpression systems, and by the heterogeneous mixture of tubulin isotypes typically isolated from higher eukaryotes. The budding yeast, Saccharomyces cerevisiae, has emerged as a leading system for tubulin structure-function analysis. Yeast cells encode a single beta-tubulin gene and can be engineered to express just one of two alpha isotypes. Moreover, yeast allows site-directed modification of tubulin genes at the endogenous loci expressed under the native promoter and regulatory elements. These advantageous features provide a homogeneous and controlled environment for analysis of the functional consequences of specific mutations. Here, we present the techniques to generate site-specific tubulin mutations in diploid and haploid cells, assess the ability of the mutated protein to support cell viability, measure overall microtubule stability, and define changes in the specific parameters of microtubule dynamic instability. We also outline strategies to determine whether mutations disrupt interactions with microtubule-associated proteins. Microtubule-based functions in yeast are well defined, which allows the observed changes in microtubule properties to be related to the role of microtubules in specific cellular processes.
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Affiliation(s)
- Anna Luchniak
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, Illinois, USA
| | - Yusuke Fukuda
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, Illinois, USA
| | - Mohan L. Gupta
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, Illinois, USA
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8
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Drummond DR, Kain S, Newcombe A, Hoey C, Katsuki M, Cross RA. Purification of tubulin from the fission yeast Schizosaccharomyces pombe. Methods Mol Biol 2011; 777:29-55. [PMID: 21773919 DOI: 10.1007/978-1-61779-252-6_3] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The fission yeast Schizosaccharomyces pombe is an attractive source of tubulin for biochemical experiments as it contains few tubulin isoforms and is amenable to genetic manipulation. We describe the preparation of milligram quantities of highly purified native tubulin from S. pombe suitable for use in microtubule dynamics assays as well as structural and other biochemical studies. S. pombe cells are grown in bulk in a fermenter and then lysed using a bead mill. The soluble protein fraction is bound to anion-exchange chromatography resin by batch binding, packed in a -chromatography column and eluted by a salt gradient. The tubulin-containing fraction is ammonium sulphate precipitated to further concentrate and purify the protein. A round of high-resolution anion-exchange chromatography is carried out before a cycle of polymerisation and depolymerisation to select functional tubulin. Gel filtration is used to remove residual contaminants before a final desalting step. The purified tubulin is concentrated, and then frozen and stored in liquid nitrogen.
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Affiliation(s)
- Douglas R Drummond
- Centre for Mechanochemical Cell Biology, Warwick Medical School, University of Warwick, Coventry, UK.
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9
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Bennett MJ, Barakat K, Huzil JT, Tuszynski J, Schriemer DC. Discovery and Characterization of the Laulimalide-Microtubule Binding Mode by Mass Shift Perturbation Mapping. ACTA ACUST UNITED AC 2010; 17:725-34. [DOI: 10.1016/j.chembiol.2010.05.019] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2010] [Revised: 05/06/2010] [Accepted: 05/10/2010] [Indexed: 01/25/2023]
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10
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Tischfield MA, Baris HN, Wu C, Rudolph G, Van Maldergem L, He W, Chan WM, Andrews C, Demer JL, Robertson RL, Mackey DA, Ruddle JB, Bird TD, Gottlob I, Pieh C, Traboulsi EI, Pomeroy SL, Hunter DG, Soul JS, Newlin A, Sabol LJ, Doherty EJ, de Uzcátegui CE, de Uzcátegui N, Collins MLZ, Sener EC, Wabbels B, Hellebrand H, Meitinger T, de Berardinis T, Magli A, Schiavi C, Pastore-Trossello M, Koc F, Wong AM, Levin AV, Geraghty MT, Descartes M, Flaherty M, Jamieson RV, Møller HU, Meuthen I, Callen DF, Kerwin J, Lindsay S, Meindl A, Gupta ML, Pellman D, Engle EC. Human TUBB3 mutations perturb microtubule dynamics, kinesin interactions, and axon guidance. Cell 2010; 140:74-87. [PMID: 20074521 PMCID: PMC3164117 DOI: 10.1016/j.cell.2009.12.011] [Citation(s) in RCA: 413] [Impact Index Per Article: 29.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2009] [Revised: 09/11/2009] [Accepted: 11/02/2009] [Indexed: 01/14/2023]
Abstract
We report that eight heterozygous missense mutations in TUBB3, encoding the neuron-specific beta-tubulin isotype III, result in a spectrum of human nervous system disorders that we now call the TUBB3 syndromes. Each mutation causes the ocular motility disorder CFEOM3, whereas some also result in intellectual and behavioral impairments, facial paralysis, and/or later-onset axonal sensorimotor polyneuropathy. Neuroimaging reveals a spectrum of abnormalities including hypoplasia of oculomotor nerves and dysgenesis of the corpus callosum, anterior commissure, and corticospinal tracts. A knock-in disease mouse model reveals axon guidance defects without evidence of cortical cell migration abnormalities. We show that the disease-associated mutations can impair tubulin heterodimer formation in vitro, although folded mutant heterodimers can still polymerize into microtubules. Modeling each mutation in yeast tubulin demonstrates that all alter dynamic instability whereas a subset disrupts the interaction of microtubules with kinesin motors. These findings demonstrate that normal TUBB3 is required for axon guidance and maintenance in mammals.
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Affiliation(s)
- Max A. Tischfield
- Department of Neurology, Children’s Hospital Boston, Boston, MA 02115 USA
- FM Kirby Neurobiology Center, Children’s Hospital Boston, Boston, MA 02115 USA
- Program in Genomics, Children’s Hospital Boston, Boston, MA 02115 USA
- The Manton Center for Orphan Disease Research, Children’s Hospital Boston, Boston, MA 02115 USA
- Program in Neuroscience, Harvard Medical School, Boston, MA 02115, USA
| | - Hagit N. Baris
- Program in Genomics, Children’s Hospital Boston, Boston, MA 02115 USA
- Department of Medicine (Genetics), Children’s Hospital Boston, Boston, MA 02115 USA
| | - Chen Wu
- Department of Neurology, Children’s Hospital Boston, Boston, MA 02115 USA
- FM Kirby Neurobiology Center, Children’s Hospital Boston, Boston, MA 02115 USA
- Program in Neuroscience, Harvard Medical School, Boston, MA 02115, USA
| | - Guenther Rudolph
- University Eye Hospital, Ludwig-Maximilians-University, Munich, Germany
| | - Lionel Van Maldergem
- Centre de génétique humaine Université de Liège, Domaine universitaire du Sart-Tilman, B-4000 Liège, Belgium
| | - Wei He
- Department of Neurology, Children’s Hospital Boston, Boston, MA 02115 USA
- FM Kirby Neurobiology Center, Children’s Hospital Boston, Boston, MA 02115 USA
- Program in Genomics, Children’s Hospital Boston, Boston, MA 02115 USA
| | - Wai-Man Chan
- Department of Neurology, Children’s Hospital Boston, Boston, MA 02115 USA
- FM Kirby Neurobiology Center, Children’s Hospital Boston, Boston, MA 02115 USA
- Program in Genomics, Children’s Hospital Boston, Boston, MA 02115 USA
- Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA
| | - Caroline Andrews
- Department of Neurology, Children’s Hospital Boston, Boston, MA 02115 USA
- FM Kirby Neurobiology Center, Children’s Hospital Boston, Boston, MA 02115 USA
- Program in Genomics, Children’s Hospital Boston, Boston, MA 02115 USA
- Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA
| | - Joseph L. Demer
- Department of Ophthalmology and Jules Stein Eye Institute, David Geffen Medical School at University of California Los Angeles
- Department of Neurology, David Geffen Medical School at University of California Los Angeles
- Neuroscience Interdepartmental Program, David Geffen Medical School at University of California Los Angeles
- Bioengineering Interdepartmental Program, David Geffen Medical School at University of California Los Angeles
| | | | - David A. Mackey
- Centre for Eye Research Australia, Department of Ophthalmology, University of Melbourne, Royal Victorian Eye and Ear Hospital, East Melbourne, Victoria, 3002, Australia
- Department of Ophthalmology, Royal Hobart Hospital, University of Tasmania, Hobart Tasmania, 7000, Australia
| | - Jonathan B. Ruddle
- Centre for Eye Research Australia, Department of Ophthalmology, University of Melbourne, Royal Victorian Eye and Ear Hospital, East Melbourne, Victoria, 3002, Australia
| | - Thomas D. Bird
- Department of Neurology and the Department of Medicine, University of Washington School of Medicine, Seattle, WA 98195, USA
- GRECC, VA Puget Sound Health Care System, Seattle, WA
| | - Irene Gottlob
- Ophthalmology Group, University of Leicester, Leicester, LE2 7LX, UK
| | - Christina Pieh
- University Eye Hospital, University of Freiburg, Killianstr. 6, 79106 Freiburg, Germany
| | - Elias I. Traboulsi
- Cole Eye Institute, Cleveland Clinic i32, 9500 Euclid Avenue Cleveland, OH 44195
| | - Scott L. Pomeroy
- Department of Neurology, Children’s Hospital Boston, Boston, MA 02115 USA
- FM Kirby Neurobiology Center, Children’s Hospital Boston, Boston, MA 02115 USA
- Program in Neuroscience, Harvard Medical School, Boston, MA 02115, USA
- Department of Neurology, Harvard Medical School, Boston, MA 02115, USA
| | - David G. Hunter
- Department of Ophthalmology, Children’s Hospital Boston, Boston, MA 02115 USA
| | - Janet S. Soul
- Department of Neurology, Children’s Hospital Boston, Boston, MA 02115 USA
- Department of Neurology, Harvard Medical School, Boston, MA 02115, USA
| | - Anna Newlin
- Center for Medical Genetics, NorthShore University HealthSystem, Evanston, IL 60201
| | - Louise J. Sabol
- Department of Ophthalmology, Geisinger Medical Institute, Danville, Pennsylvania
| | - Edward J. Doherty
- Atlantic Health Science Centre, Saint John Regional Hospital, Saint John New Brunswick, Canada
| | - Clara E. de Uzcátegui
- Instituto de Oftalmologia, Av. Cajigal 48. Piso 3 Consultorio 8. San Bernardino, Caracas 1010 Venezuela
| | - Nicolas de Uzcátegui
- Department of Ophthalmology, Upstate Medical University SUNY. Eye Consultants Of Syracuse, 1101 Erie Blvd. East Ste 100. Syracuse NY 13210
| | | | - Emin C. Sener
- Department of Ophthalmology, Hacettepe University Hospitals, Ankara 06100, Turkey
| | - Bettina Wabbels
- Department of Ophthalmology, University of Bonn, Abbestr. 2, D-53127, Bonn, Germany
| | - Heide Hellebrand
- Department of Obstetrics and Gynaecology, Klinikum rechts der Isar, Technische Universität München, Ismaningerstr 22, 81675 Munich, Germany
| | - Thomas Meitinger
- Institute of Human Genetics, Klinikum rechts der Isar, Technische Universität München, Ismaningerstr 22, 81675 Munich, Germany
- Institute of Human Genetics, Helmholtz Zentrum München, Ingolstädter Landstr. 1, 85764 Neuherberg, Germany
| | - Teresa de Berardinis
- Department of Ophthalmologic Sciences, Faculty of Medicine and Surgery, University “Federico II”, Naples, Italy
| | - Adriano Magli
- Department of Ophthalmologic Sciences, Faculty of Medicine and Surgery, University “Federico II”, Naples, Italy
| | | | - Marco Pastore-Trossello
- Department of Neuro-Radiology, S.Orsola-Malpighi Hospital via Albertoni, 15, 40138, Bologna, Italy
| | - Feray Koc
- Department of Ophthalmology and Strabismus, and Neuroophthalmology, Acıbadem University Kocaeli Hospital, Kocaeli 41100 Turkey
| | - Agnes M. Wong
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, Toronto, Ontario Canada
| | - Alex V. Levin
- Pediatric Ophthalmology and Ocular Genetics, Wills Eye Institute, Philadelphia, PA
| | | | - Maria Descartes
- Department of Genetics, University of Alabama at Birmingham, Birmingham, Alabama
| | - Maree Flaherty
- Department of Ophthalmology, The Children’s Hospital at Westmead, Sydney, Australia
| | - Robyn V. Jamieson
- Department of Clinical Genetics, The Children’s Hospital at Westmead, Sydney, Australia
- The University of Sydney, Sydney, Australia
| | - H. U. Møller
- Department of Ophthalmology, Viborg Hospital, DK 8000 Viborg Denmark
| | - Ingo Meuthen
- Department of Hematology-Oncology, Kliniken der Stadt Köln, Neufelderstr. 32, 51067 Köln, Germany
| | - David F. Callen
- Breast Cancer Genetics Group, School of Medicine, University of Adelaide, Australia
| | - Janet Kerwin
- Institute of Human Genetics, Newcastle University, Newcastle upon Tyne NE1 3BZ, UK
| | - Susan Lindsay
- Institute of Human Genetics, Newcastle University, Newcastle upon Tyne NE1 3BZ, UK
- MRC-Wellcome Trust Human Developmental Biology Resource (Newcastle), Newcastle University, Newcastle upon Tyne NE1 3BZ, UK
| | - Alfons Meindl
- Department of Obstetrics and Gynaecology, Klinikum rechts der Isar, Technische Universität München, Ismaningerstr 22, 81675 Munich, Germany
| | - Mohan L. Gupta
- Division of Hematology/Oncology, Harvard Medical School, Boston, MA 02115, USA
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA 02115, USA
| | - David Pellman
- Division of Hematology/Oncology, Children’s Hospital Boston, Boston, MA 02115 USA
- Division of Hematology/Oncology, Harvard Medical School, Boston, MA 02115, USA
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA 02115, USA
| | - Elizabeth C. Engle
- Department of Neurology, Children’s Hospital Boston, Boston, MA 02115 USA
- FM Kirby Neurobiology Center, Children’s Hospital Boston, Boston, MA 02115 USA
- Program in Genomics, Children’s Hospital Boston, Boston, MA 02115 USA
- The Manton Center for Orphan Disease Research, Children’s Hospital Boston, Boston, MA 02115 USA
- Department of Medicine (Genetics), Children’s Hospital Boston, Boston, MA 02115 USA
- Department of Ophthalmology, Children’s Hospital Boston, Boston, MA 02115 USA
- Program in Neuroscience, Harvard Medical School, Boston, MA 02115, USA
- Department of Neurology, Harvard Medical School, Boston, MA 02115, USA
- Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA
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11
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Secondary mutations correct fitness defects in Toxoplasma gondii with dinitroaniline resistance mutations. Genetics 2008; 180:845-56. [PMID: 18780736 DOI: 10.1534/genetics.108.092494] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Dinitroanilines (oryzalin, trifluralin, ethafluralin) disrupt microtubules in protozoa but not in vertebrate cells, causing selective death of intracellular Toxoplasma gondii parasites without affecting host cells. Parasites containing alpha1-tubulin point mutations are dinitroaniline resistant but show increased rates of aberrant replication relative to wild-type parasites. T. gondii parasites bearing the F52Y mutation were previously demonstrated to spontaneously acquire two intragenic mutations that decrease both resistance levels and replication defects. Parasites bearing the G142S mutation are largely dependent on oryzalin for viable growth in culture. We isolated 46 T. gondii lines that have suppressed microtubule defects associated with the G142S or the F52Y mutations by acquiring secondary mutations. These compensatory mutations were alpha1-tubulin pseudorevertants or extragenic suppressors (the majority alter the beta1-tubulin gene). Many secondary mutations were located in tubulin domains that suggest that they function by destabilizing microtubules. Most strikingly, we identified seven novel mutations that localize to an eight-amino-acid insert that stabilizes the alpha1-tubulin M loop, including one (P364R) that acts as a compensatory mutation in both F52Y and G142S lines. These lines have reduced dinitroaniline resistance but most perform better than parental lines in competition assays, indicating that there is a trade-off between resistance and replication fitness.
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Affiliation(s)
- R G Burns
- Biophysics Section, Blackett Laboratory, Imperial College of Science, Technology and Medicine, London, UK SW7 2BZ
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13
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Gupta ML, Bode CJ, Thrower DA, Pearson CG, Suprenant KA, Bloom KS, Himes RH. beta-Tubulin C354 mutations that severely decrease microtubule dynamics do not prevent nuclear migration in yeast. Mol Biol Cell 2002; 13:2919-32. [PMID: 12181356 PMCID: PMC117952 DOI: 10.1091/mbc.e02-01-0003] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Microtubule dynamics are influenced by interactions of microtubules with cellular factors and by changes in the primary sequence of the tubulin molecule. Mutations of yeast beta-tubulin C354, which is located near the binding site of some antimitotic compounds, reduce microtubule dynamicity greater than 90% in vivo and in vitro. The resulting intrinsically stable microtubules allowed us to determine which, if any, cellular processes are dependent on dynamic microtubules. The average number of cytoplasmic microtubules decreased from 3 in wild-type to 1 in mutant cells. The single microtubule effectively located the bud site before bud emergence. Although spindles were positioned near the bud neck at the onset of anaphase, the mutant cells were deficient in preanaphase spindle alignment along the mother-bud axis. Spindle microtubule dynamics and spindle elongation rates were also severely depressed in the mutants. The pattern and extent of cytoplasmic microtubule dynamics modulation through the cell cycle may reveal the minimum dynamic properties required to support growth. The ability to alter intrinsic microtubule dynamics and determine the in vivo phenotype of cells expressing the mutant tubulin provides a critical advance in assessing the dynamic requirements of an essential gene function.
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Affiliation(s)
- Mohan L Gupta
- Department of Molecular Biosciences, University of Kansas, Lawrence 66045, USA
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Gupta ML, Bode CJ, Dougherty CA, Marquez RT, Himes RH. Mutagenesis of beta-tubulin cysteine residues in Saccharomyces cerevisiae: mutation of cysteine 354 results in cold-stable microtubules. CELL MOTILITY AND THE CYTOSKELETON 2001; 49:67-77. [PMID: 11443737 DOI: 10.1002/cm.1021] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Cysteine residues play important roles in the control of tubulin function. To determine which of the six cysteine residues in beta-tubulin are critical to tubulin function, we mutated the cysteines in Saccharomyces cerevisiae beta-tubulin individually to alanine and serine residues. Of the twelve mutations, only three produced significant effects: C12S, C354A, and C354S. The C12S mutation was lethal in the haploid, but the C12A mutation had no observable phenotype. Based on interactive views of the electron crystallographic structure of tubulin, we suggest that substitution of serine for cysteine at this position has a destabilizing effect on the interaction of tubulin with the exchangeable GTP. The two C354 mutations, although not lethal, produced dramatic effects on microtubules and cellular processes that require microtubules. The C354 mutant cells had decreased growth rates, a slowed mitosis, increased resistance to benomyl, and impaired nuclear migration and spindle assembly. The C354A mutation produced a more severe phenotype than the C354S mutation: the haploid cells had chromosome segregation defects, only 50% of cells in a culture were viable, and a significant percentage of the cells were misshapened. Cytoplasmic microtubules in the C354S and C354A cells were longer than in the control strain and spindle structures appeared shorter and thicker. Both cytoplasmic and spindle microtubules in the two C354 mutants were extremely stable to cold temperature. After 24 h at 4 degrees C, the microtubules were still present and, in fact, very long and thick tubulin polymers had formed. Evidence exists to indicate that the C354 residue in mammalian tubulin is near the colchicine binding site and the electron crystal structure of tubulin places the residue at the interface between the alpha- and beta-subunits. The sulfhydryl group is situated in a polar environment, which may explain why the alanine mutation is more severe than the serine mutation. When the C12S and the two C354 mutations were made in a diploid strain, the mutated tubulin was incorporated into microtubules and the resulting heterozygotes had phenotypes that were intermediate between those of the mutated haploids and the wild-type strains. The results suggest that the C12 and C354 residues play important roles in the structure and function of tubulin.
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Affiliation(s)
- M L Gupta
- Department of Molecular Biosciences, University of Kansas, Lawrence, Kansas 66045-2106, USA
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15
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Detrich HW, Parker SK, Williams RC, Nogales E, Downing KH. Cold adaptation of microtubule assembly and dynamics. Structural interpretation of primary sequence changes present in the alpha- and beta-tubulins of Antarctic fishes. J Biol Chem 2000; 275:37038-47. [PMID: 10956651 DOI: 10.1074/jbc.m005699200] [Citation(s) in RCA: 126] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The microtubules of Antarctic fishes, unlike those of homeotherms, assemble at very low temperatures (-1.8 degrees C). The adaptations that enhance assembly of these microtubules are intrinsic to the tubulin dimer and reduce its critical concentration for polymerization at 0 degrees C to approximately 0.9 mg/ml (Williams, R. C., Jr., Correia, J. J., and DeVries, A. L. (1985) Biochemistry 24, 2790-2798). Here we demonstrate that microtubules formed by pure brain tubulins of Antarctic fishes exhibit slow dynamics at both low (5 degrees C) and high (25 degrees C) temperatures; the rates of polymer growth and shortening and the frequencies of interconversion between these states are small relative to those observed for mammalian microtubules (37 degrees C). To investigate the contribution of tubulin primary sequence variation to the functional properties of the microtubules of Antarctic fishes, we have sequenced brain cDNAs that encode 9 alpha-tubulins and 4 beta-tubulins from the yellowbelly rockcod Notothenia coriiceps and 4 alpha-tubulins and 2 beta-tubulins from the ocellated icefish Chionodraco rastrospinosus. The tubulins of these fishes were found to contain small sets of unique or rare residue substitutions that mapped to the lateral, interprotofilament surfaces or to the interiors of the alpha- and beta-polypeptides; longitudinal interaction surfaces are not altered in the fish tubulins. Four changes (A278T and S287T in alpha; S280G and A285S in beta) were present in the S7-H9 interprotofilament "M" loops of some monomers and would be expected to increase the flexibility of these regions. A fifth lateral substitution specific to the alpha-chain (M302L or M302F) may increase the hydrophobicity of the interprotofilament interaction. Two hydrophobic substitutions (alpha:S187A in helix H5 and beta:Y202F in sheet S6) may act to stabilize the monomers in conformations favorable to polymerization. We propose that cold adaptation of microtubule assembly in Antarctic fishes has occurred in part by evolutionary restructuring of the lateral surfaces and the cores of the tubulin monomers.
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Affiliation(s)
- H W Detrich
- Department of Biology, Northeastern University, Boston, Massachusetts 02115, USA
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17
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Rasmussen RK, Ji H, Eddes JS, Moritz RL, Reid GE, Simpson RJ, Dorow DS. Two-dimensional electrophoretic analysis of mixed lineage kinase 2 N-terminal domain binding proteins. Electrophoresis 1998; 19:809-17. [PMID: 9629920 DOI: 10.1002/elps.1150190535] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The mixed lineage kinase 2 (MLK2) protein contains several structurally distinct domains including an src homology (SH) 3 domain, a kinase catalytic domain, two leucine zippers, a basic motif and a cdc42/rac interactive binding motif. These domains have been recognized mainly for their involvement in protein-protein interactions in signal transduction networks. The SH3 domain in particular has been implicated in control of signaling events. To identify proteins that interact with MLK2, the N-terminal 100 amino acids, including the SH3 domain, were expressed as a glutathione S-transferase (GST) fusion protein. This fusion protein (MLK2N) was used as an affinity ligand to isolate binding proteins from lysates of 35S-radiolabeled MDA-MB231 breast carcinoma cells. When the radiolabeled binding proteins were subjected to 2-DE, proteins of Mr 55,000, 31,500 and 34,000 bound consistently to the MLK2N domain fusion protein, but not to the GST control. Two of the binding proteins were isolated from whole cell lysates by preparative 2-DE and subjected to in-gel digestion and capillary or microbore reverse-phase high performance liquid chromatography (RP-HPLC). Resultant peptides were analyzed by peptide mass fingerprinting, N-terminal Edman degradation or tandem mass spectrometry. The 55,000 protein was identified as the cytoskeletal protein, beta-tubulin, and this was verified by immunoblotting of proteins in the MLK2N binding fraction with anti-tubulin antibodies. The 31,500 protein has been identified as prohibitin, a protein that has been implicated in both signal transduction and cell cycle arrest.
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Affiliation(s)
- R K Rasmussen
- Trescowthick Research Center, Peter MacCallum Cancer Institute, Melbourne, Victoria, Australia
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Abstract
The polymerization dynamics of microtubules are central to their biological functions. Polymerization dynamics allow microtubules to adopt spatial arrangements that can change rapidly in response to cellular needs and, in some cases, to perform mechanical work. Microtubules utilize the energy of GTP hydrolysis to fuel a unique polymerization mechanism termed dynamic instability. In this review, we first describe progress toward understanding the mechanism of dynamic instability of pure tubulin and then discuss the function and regulation of microtubule dynamic instability in living cells.
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Affiliation(s)
- A Desai
- Department of Biochemistry and Biophysics, University of California, San Francisco 94143, USA.
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Affiliation(s)
- B Winsor
- Institut de Biologie Moléculaire et Cellulaire, UPR 9005 du CNRS, Strasbourg, France
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Burns RG. Identification of two new members of the tubulin family. CELL MOTILITY AND THE CYTOSKELETON 1995; 31:255-8. [PMID: 7553912 DOI: 10.1002/cm.970310402] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Analysis of the delta- and epsilon-tubulin sequences indicates that they both consist of two structural domains of which the N-terminal domain can bind to alpha/beta heterodimers while the C-terminal domain probably binds to a non-tubulin protein. Both additional tubulins probably bind GTP but lack GTPase activity, while their synthesis requires the TCP1 chaperonine but is not autoregulated. Although these properties resemble those of gamma-tubulin, the low sequence identity (Table I) demonstrates that the gamma-, delta-, and epsilon-proteins should be classed as different members of the tubulin family. The identification of these additional members is unexpected. Examination of the cellular expression and distribution of the delta- and epsilon-tubulins, and whether other organisms contain homologous genes, may reveal further features of the eukaryotic cytoskeleton.
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Affiliation(s)
- R G Burns
- Biophysics Section, Blackett Laboratory, Imperial College of Science, Technology and Medicine, London, United Kingdom
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