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Molines AT, Lemière J, Gazzola M, Steinmark IE, Edrington CH, Hsu CT, Real-Calderon P, Suhling K, Goshima G, Holt LJ, Thery M, Brouhard GJ, Chang F. Physical properties of the cytoplasm modulate the rates of microtubule polymerization and depolymerization. Dev Cell 2022; 57:466-479.e6. [PMID: 35231427 PMCID: PMC9319896 DOI: 10.1016/j.devcel.2022.02.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 11/01/2021] [Accepted: 01/31/2022] [Indexed: 11/20/2022]
Abstract
The cytoplasm is a crowded, visco-elastic environment whose physical properties change according to physiological or developmental states. How the physical properties of the cytoplasm impact cellular functions in vivo remains poorly understood. Here, we probe the effects of cytoplasmic concentration on microtubules by applying osmotic shifts to fission yeast, moss, and mammalian cells. We show that the rates of both microtubule polymerization and depolymerization scale linearly and inversely with cytoplasmic concentration; an increase in cytoplasmic concentration decreases the rates of microtubule polymerization and depolymerization proportionally, whereas a decrease in cytoplasmic concentration leads to the opposite. Numerous lines of evidence indicate that these effects are due to changes in cytoplasmic viscosity rather than cellular stress responses or macromolecular crowding per se. We reconstituted these effects on microtubules in vitro by tuning viscosity. Our findings indicate that, even in normal conditions, the viscosity of the cytoplasm modulates the reactions that underlie microtubule dynamic behaviors.
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Affiliation(s)
- Arthur T Molines
- Department of Cell and Tissue Biology, University of California, San Francisco, USA; Marine Biological Laboratory, Woods Hole, MA 02543, USA.
| | - Joël Lemière
- Department of Cell and Tissue Biology, University of California, San Francisco, USA
| | - Morgan Gazzola
- University of Grenoble-Alpes, CEA, CNRS, INRA, Interdisciplinary Research Institute of Grenoble, Laboratoire de Phyiologie Cellulaire & Vegétale, CytoMorpho Lab, 38054 Grenoble, France
| | | | | | - Chieh-Ting Hsu
- Department of Physics, McGill University, Montréal, Quebec, Canada
| | - Paula Real-Calderon
- Department of Cell and Tissue Biology, University of California, San Francisco, USA
| | - Klaus Suhling
- Department of Physics, King's College London, London, UK
| | - Gohta Goshima
- Sugashima Marine Biological Laboratory and Division of Biological Science, Graduate School of Science, Nagoya University, Toba City, Mie, Japan; Marine Biological Laboratory, Woods Hole, MA 02543, USA
| | - Liam J Holt
- Institute for Systems Genetics, New York University Langone Health, New York, NY 10016, USA; Marine Biological Laboratory, Woods Hole, MA 02543, USA
| | - Manuel Thery
- University of Grenoble-Alpes, CEA, CNRS, INRA, Interdisciplinary Research Institute of Grenoble, Laboratoire de Phyiologie Cellulaire & Vegétale, CytoMorpho Lab, 38054 Grenoble, France; Université de Paris, INSERM, CEA, Institut de Recherche Saint Louis, U 976, CytoMorpho Lab, 75010 Paris, France
| | - Gary J Brouhard
- Department of Biology, McGill University, Montréal, Quebec, Canada
| | - Fred Chang
- Department of Cell and Tissue Biology, University of California, San Francisco, USA; Marine Biological Laboratory, Woods Hole, MA 02543, USA.
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Kalra AP, Patel SD, Eakins BB, Riddell S, Kumar P, Winter P, Preto J, Carlson KW, Lewis JD, Rezania V, Tuszyński JA, Shankar K. Revealing and Attenuating the Electrostatic Properties of Tubulin and Its Polymers. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2021; 17:e2003560. [PMID: 33295102 DOI: 10.1002/smll.202003560] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 10/17/2020] [Indexed: 06/12/2023]
Abstract
Tubulin is an electrostatically negative protein that forms cylindrical polymers termed microtubules, which are crucial for a variety of intracellular roles. Exploiting the electrostatic behavior of tubulin and microtubules within functional microfluidic and optoelectronic devices is limited due to the lack of understanding of tubulin behavior as a function of solvent composition. This work displays the tunability of tubulin surface charge using dimethyl sulfoxide (DMSO) for the first time. Increasing the DMSO volume fractions leads to the lowering of tubulin's negative surface charge, eventually causing it to become positive in solutions >80% DMSO. As determined by electrophoretic mobility measurements, this change in surface charge is directionally reversible, i.e., permitting control between -1.5 and + 0.2 cm2 (V s)-1 . When usually negative microtubules are exposed to these conditions, the positively charged tubulin forms tubulin sheets and aggregates, as revealed by an electrophoretic transport assay. Fluorescence-based experiments also indicate that tubulin sheets and aggregates colocalize with negatively charged g-C3 N4 sheets while microtubules do not, further verifying the presence of a positive surface charge. This study illustrates that tubulin and its polymers, in addition to being mechanically robust, are also electrically tunable.
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Affiliation(s)
- Aarat P Kalra
- Department of Physics, University of Alberta, 11335 Saskatchewan Dr NW, Edmonton, Alberta, T6G 2M9, Canada
| | - Sahil D Patel
- Department of Physics, University of Alberta, 11335 Saskatchewan Dr NW, Edmonton, Alberta, T6G 2M9, Canada
| | - Boden B Eakins
- Department of Physics, University of Alberta, 11335 Saskatchewan Dr NW, Edmonton, Alberta, T6G 2M9, Canada
| | - Saralyn Riddell
- Department of Electrical and Computer Engineering, University of Alberta, 9107-116 St, Edmonton, Alberta, T6G 2V4, Canada
| | - Pawan Kumar
- Department of Electrical and Computer Engineering, University of Alberta, 9107-116 St, Edmonton, Alberta, T6G 2V4, Canada
| | - Philip Winter
- Department of Oncology, University of Alberta, Edmonton, Alberta, T6G 1Z2, Canada
| | - Jordane Preto
- Centre de Recherche en Cancérologie de Lyon, INSERM 1052, CNRS 5286, Université Claude Bernard Lyon 1, Lyon, 69008, France
| | - Kris W Carlson
- Department of Neurosurgery, Beth Israel Deaconess Medical Centre, Harvard Medical School, Boston, MA, 02215, USA
| | - John D Lewis
- Department of Oncology, University of Alberta, Edmonton, Alberta, T6G 1Z2, Canada
| | - Vahid Rezania
- Department of Physical Sciences, MacEwan University, Edmonton, Alberta, T5J 4S2, Canada
| | - Jack A Tuszyński
- Department of Physics, University of Alberta, 11335 Saskatchewan Dr NW, Edmonton, Alberta, T6G 2M9, Canada
| | - Karthik Shankar
- Department of Electrical and Computer Engineering, University of Alberta, 9107-116 St, Edmonton, Alberta, T6G 2V4, Canada
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3
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Kalra AP, Kar P, Preto J, Rezania V, Dogariu A, Lewis JD, Tuszynski JA, Shankar K. Behavior of α, β tubulin in DMSO-containing electrolytes. NANOSCALE ADVANCES 2019; 1:3364-3371. [PMID: 36133560 PMCID: PMC9418024 DOI: 10.1039/c9na00035f] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2019] [Accepted: 06/18/2019] [Indexed: 06/11/2023]
Abstract
α, β-tubulin is a cytoskeletal protein that forms cylindrical structures termed microtubules, which are crucial to the cell for a variety of roles. Microtubules are frequently modelled as one-dimensional bionanowires that act as ion transporters in the cell. In this work, we used dynamic light scattering (DLS) to measure the hydrodynamic diameter of tubulin in the presence of a polar aprotic co-solvent. We found that the hydrodynamic diameter increased with increasing DMSO volume fraction, almost doubling at 20% DMSO. To evaluate if this was due to an enlarged solvation shell, we performed reference interaction site model (RISM) simulations and found that the extent of solvation was unchanged. Using fluorescence microscopy, we then showed that tubulin was polymerization competent in the presence of colchicine, and thus inferred the presence of oligomers in the presence of DMSO, which points to its mechanism of action as a microtubule polymerization enhancing agent. Tubulin oligomers are known to form when microtubules depolymerize and are controversially implicated in microtubule polymerization. We show that DLS may be used to monitor early-state microtubule polymerization and is a viable alternative to fluorescence and electron microscopy-based methods. Our findings showing that DMSO causes tubulin oligomerization are thus of critical importance, both for creating bio-inspired nanotechnology and determining its biophysical roles in the cell.
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Affiliation(s)
- Aarat P Kalra
- Department of Physics, University of Alberta 11335 Saskatchewan Dr NW Edmonton Alberta T6G 2M9 Canada
| | - Piyush Kar
- Department of Electrical and Computer Engineering, University of Alberta 9107-116 St Edmonton Alberta T6G 2V4 Canada
| | - Jordane Preto
- Department of Physics, University of Alberta 11335 Saskatchewan Dr NW Edmonton Alberta T6G 2M9 Canada
| | - Vahid Rezania
- Department of Physical Sciences, MacEwan University Edmonton Alberta T5J 4S2 Canada
| | - Aristide Dogariu
- CREOL, The College of Optics and Photonics, University of Central Florida Orlando FL 32816 USA
| | - John D Lewis
- Department of Oncology, University of Alberta Edmonton Alberta T6G 1Z2 Canada
| | - Jack A Tuszynski
- Department of Physics, University of Alberta 11335 Saskatchewan Dr NW Edmonton Alberta T6G 2M9 Canada
- Department of Oncology, University of Alberta Edmonton Alberta T6G 1Z2 Canada
| | - Karthik Shankar
- Department of Electrical and Computer Engineering, University of Alberta 9107-116 St Edmonton Alberta T6G 2V4 Canada
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4
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Inhibition of dendritic spine extension through acrolein conjugation with α-, β-tubulin proteins. Int J Biochem Cell Biol 2019; 113:58-66. [PMID: 31150838 DOI: 10.1016/j.biocel.2019.05.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2019] [Revised: 05/24/2019] [Accepted: 05/27/2019] [Indexed: 11/23/2022]
Abstract
We have recently found that conjugation of acrolein with a 50 kDa protein(s) is strongly associated with tissue damage during brain infarction. In the current study, the identity and function of the 50 kDa protein(s) conjugated with acrolein during brain infarction were investigated. The 50 kDa protein(s) conjugated with acrolein were identified as α- and β-tubulins. Ten cysteine residues in α- and β-tubulins (Cys25, 295, 347 and 376 in α-tubulin and Cys12, 129, 211, 239, 303 and 354 in β-tubulin) were mainly conjugated with acrolein. Since two cysteine residues of α-tubulin (Cys347 and 376) and four cysteine residues of β-tubulin (Cys12, 129, 239 and 354) were located at the interaction site of α- and β-tubulins, association between α- and β-tubulins to form microtubules was strongly inhibited by conjugation with acrolein. Accordingly, dendritic spine extension consisting of microtubules was greatly inhibited in acrolein-treated Neuro2a cells. The results strongly suggest that acrolein contributes to the functional losses in brain signaling through its conjugation with α- and β-tubulins.
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5
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Zhu C, Zuo Y, Liang B, Yue H, Yue X, Wen G, Wang R, Quan J, Du J, Bu X. Distinct tubulin dynamics in cancer cells explored using a highly tubulin-specific fluorescent probe. Chem Commun (Camb) 2015. [PMID: 26214302 DOI: 10.1039/c5cc04927j] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
A highly specific fluorescent probe (OC9) was discovered exhibiting tubulin-specific affinity fluorescence, which allowed selective labeling of cellular tubulin in microtubules. Moreover, distinct tubulin dynamics in various cellular bio-settings such as drug resistant or epithelial-mesenchymal transition (EMT) cancer cells were directly observed for the first time via OC9 staining.
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Affiliation(s)
- Cuige Zhu
- School of Pharmaceutical Sciences, Sun Yat-sen University, GuangZhou 510006, China.
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6
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Sperm flagellum volume determines freezability in red deer spermatozoa. PLoS One 2014; 9:e112382. [PMID: 25380133 PMCID: PMC4224448 DOI: 10.1371/journal.pone.0112382] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Accepted: 10/07/2014] [Indexed: 11/19/2022] Open
Abstract
The factors affecting the inter-individual differences in sperm freezability is a major line of research in spermatology. Poor sperm freezability is mainly characterised by a low sperm velocity, which in turn is associated with low fertility rates in most animal species. Studies concerning the implications of sperm morphometry on freezability are quite limited, and most of them are based on sperm head size regardless of the structural parts of the flagellum, which provides sperm motility. Here, for the first time, we determined the volumes of the flagellum structures in fresh epididymal red deer spermatozoa using a stereological method under phase contrast microscopy. Sperm samples from thirty-three stags were frozen and classified as good freezers (GF) or bad freezers (BF) at two hours post-thawing using three sperm kinetic parameters which are strongly correlated with fertility in this species. Fourteen stags were clearly identified as GF, whereas nineteen were BF. No significant difference in sperm head size between the two groups was found. On the contrary, the GF exhibited a lower principal piece volume than the BF (6.13 µm3 vs 6.61 µm3, respectively, p = 0.006). The volume of the flagellum structures showed a strong negative relationship with post-thawing sperm velocity. For instance, the volume of the sperm principal piece was negatively correlated with sperm velocity at two hours post-thawing (r = −0.60; p<0.001). Our results clearly show that a higher volume of the sperm principal piece results in poor freezability, and highlights the key role of flagellum size in sperm cryopreservation success.
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7
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Nicholas MP, Rao L, Gennerich A. Covalent immobilization of microtubules on glass surfaces for molecular motor force measurements and other single-molecule assays. Methods Mol Biol 2014; 1136:137-69. [PMID: 24633798 PMCID: PMC4258907 DOI: 10.1007/978-1-4939-0329-0_9] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Rigid attachment of microtubules (MTs) to glass cover slip surfaces is a prerequisite for a variety of microscopy experiments in which MTs are used as substrates for MT-associated proteins, such as the molecular motors kinesin and cytoplasmic dynein. We present an MT-surface coupling protocol in which aminosilanized glass is formylated using the cross-linker glutaraldehyde, fluorescence-labeled MTs are covalently attached, and the surface is passivated with highly pure beta-casein. The technique presented here yields rigid MT immobilization while simultaneously blocking the remaining glass surface against nonspecific binding by polystyrene optical trapping microspheres. This surface chemistry is straightforward and relatively cheap and uses a minimum of specialized equipment or hazardous reagents. These methods provide a foundation for a variety of optical tweezers experiments with MT-associated molecular motors and may also be useful in other assays requiring surface-immobilized proteins.
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Affiliation(s)
- Matthew P Nicholas
- Department of Anatomy and Structural Biology, Gruss Lipper Biophotonics Center, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY, 10461, USA
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8
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Martí-Centelles V, Burguete MI, Luis SV. Kinetic analysis for macrocyclizations involving anionic template at the transition state. ScientificWorldJournal 2012; 2012:748251. [PMID: 22666148 PMCID: PMC3347868 DOI: 10.1100/2012/748251] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2011] [Accepted: 12/19/2011] [Indexed: 12/04/2022] Open
Abstract
Several kinetic models for the macrocyclization of a C2 pseudopeptide with a dihalide through a SN2 reaction have been developed. These models not only focus on the kinetic analysis of the main macrocyclization reaction, but also consider the
competitive oligomerization/polymerization processes yielding undesired oligomeric/polymeric byproducts. The effect of anions has also been included in the kinetic models, as they can act as catalytic templates in the transition state reducing and stabilizing the transition state. The corresponding differential equation systems for each kinetic model can be solved numerically. Through a comprehensive analysis of these results, it is possible to obtain a better understanding of the different parameters that are involved in the macrocyclization reaction mechanism and to develop strategies for the optimization of the desired processes.
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Affiliation(s)
- Vicente Martí-Centelles
- Departamento de Química Inorgánica y Orgánica, Universitat Jaume I, E12071 Castellón de la Plana, Spain
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9
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Abstract
SummaryWe evaluated the effect of glycerol on the perinuclear theca (PT) of boar sperm. Samples from six ejaculates obtained from three different boars were incubated in the detergent Brij 36-T. Spermatozoa were treated with a glycerol concentration of either 2 or 4%, and incubated for 10 or 30 min; two other samples were treated with protease inhibitors (PI; leupeptin or an inhibitor commercial cocktail), mixed with 4% glycerol, and incubated for 30 min. A third glycerol-free group was used as the control. The samples were processed for electron microscopy evaluation. The PT remained intact in 78% of the control samples while, after addition of glycerol for 30 min, the proportion of spermatozoa with disrupted or absent PT increased (P < 0.05). PT was preserved in PI samples, but PT changes increased (P < 0.05). Differences due to treatment with glycerol (2 or 4%) at 10 or 30 min were not observed. These results show, to our knowledge for the first time, the adverse effect of glycerol on the integrity of the PT.
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10
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Abstract
Microtubules are one of the three primary constituents of the eukaryotic cytoskeleton and are constructed from the protein tubulin. FtsZ is a close structural homologue of tubulin within prokaryotes, and plays an important structural role during cell division. This article compares what is known about the structures that these two homologues are able to form in vivo and in vitro and examines the evidence that the water in the immediate vicinity of the structures, particularly in microtubules, may play an important role in their formation and stability. The article then examines evidence that this hydration layer might help our understanding of how the structures formed by tubulin and FtsZ are stabilised by associated proteins and selected cations. The article then considers recent studies of the charge distribution and dipole moments of tubulin and extends this work to include the electrostatic characteristics of FtsZ. There is then an examination of the ways in which the electrostatic similarities and differences between the two proteins might be related to the similarities and differences in the filamentary structures that they form.
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Affiliation(s)
- Nigel Dyer
- MOAC Doctoral Training Centre, University of Warwick, Coventry CV4 7AL.
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11
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Vogl T, Ludwig S, Goebeler M, Strey A, Thorey IS, Reichelt R, Foell D, Gerke V, Manitz MP, Nacken W, Werner S, Sorg C, Roth J. MRP8 and MRP14 control microtubule reorganization during transendothelial migration of phagocytes. Blood 2004; 104:4260-8. [PMID: 15331440 DOI: 10.1182/blood-2004-02-0446] [Citation(s) in RCA: 259] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
AbstractMRP14 (S100A9) is the major calcium-binding protein of neutrophils and monocytes. Targeted gene disruption reveals an essential role of this S100 protein for transendothelial migration of phagocytes. The underlying molecular mechanism comprises major alterations of cytoskeletal metabolism. MRP14, in complex with its binding partner MRP8 (S100A8), promotes polymerization of microtubules. MRP14 is specifically phosphorylated by p38 mitogen-activated protein kinase (MAPK). This phosphorylation inhibits MRP8/MRP14-induced tubulin polymerization. Phosphorylation of MRP14 is antagonistically regulated by binding of MRP8 and calcium. The biologic relevance of these findings is confirmed by the fact that MAPK p38 fails to stimulate migration of MRP14-/- granulocytes in vitro and MRP14-/- mice show a diminished recruitment of granulocytes into the granulation tissue during wound healing in vivo. MRP14-/- granulocytes contain significantly less polymerized tubulin, which subsequently results in minor activation of Rac1 and Cdc42 after stimulation of p38 MAPK. Thus, the complex of MRP8/MRP14 is the first characterized molecular target integrating MAPK- and calcium-dependent signals during migration of phagocytes.
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Affiliation(s)
- Thomas Vogl
- Institute of Experimental Dermatology, Department of Pediatrics, University of Münster, Röntgenstrasse 21, D-48149 Münster, Germany
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12
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Beuria TK, Krishnakumar SS, Sahar S, Singh N, Gupta K, Meshram M, Panda D. Glutamate-induced assembly of bacterial cell division protein FtsZ. J Biol Chem 2003; 278:3735-41. [PMID: 12446699 DOI: 10.1074/jbc.m205760200] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The polymerization of FtsZ is a finely regulated process that plays an essential role in the bacterial cell division process. However, only a few modulators of FtsZ polymerization are known. We identified monosodium glutamate as a potent inducer of FtsZ polymerization. In the presence of GTP, glutamate enhanced the rate and extent of polymerization of FtsZ in a concentration-dependent manner; approximately 90% of the protein was sedimented as polymer in the presence of 1 m glutamate. Electron micrographs of glutamate-induced polymers showed large filamentous structures with extensive bundling. Furthermore, glutamate strongly stabilized the polymers against dilution-induced disassembly, and it decreased the GTPase activity of FtsZ. Calcium induced FtsZ polymerization and bundling of FtsZ polymers; interestingly, although 1 m glutamate produced a larger light-scattering signal than produced by 10 mm calcium, the amount of polymer sedimented in the presence of 1 m glutamate and 10 mm calcium was similar. Thus, the increased light scattering in the presence of glutamate must be due to its ability to induce more extensive bundling of FtsZ polymers than calcium. The data suggest that calcium and glutamate might induce FtsZ polymerization by different mechanisms.
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Affiliation(s)
- Tushar K Beuria
- School of Biosciences and Bioengineering, Indian Institute of Technology, Bombay, Powai, Mumbai 400 076, India
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13
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Vater W, Böhm KJ, Unger E. Tubulin assembly in the presence of calcium ions and taxol: microtubule bundling and formation of macrotubule-ring complexes. CELL MOTILITY AND THE CYTOSKELETON 1997; 36:76-83. [PMID: 8986379 DOI: 10.1002/(sici)1097-0169(1997)36:1<76::aid-cm7>3.0.co;2-f] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
It has been confirmed that taxol is able to prevent Ca(2+)-induced inhibition of microtubule formation from tubulin in the presence of microtubule-associated proteins. However, by means of electron microscopy and scanning force microscopy it could be demonstrated that assembly in the presence of Ca2+ and taxol leads to structural aberrations. The kind of aberration depends on the order of addition of taxol and Ca2+ to tubulin. When taxol was added first, microtubules were formed preferentially. But, these microtubules typically associated with each other by close wall-to-wall alignments or they formed complexes with some C-shaped protofilament ribbons, resulting in microtubule bundles or doublet- and triplet-like microtubule structures, respectively. When Ca2+ was added first, macrotubules, rings, and ring crystals were the dominant assembly products. Mostly, the macrotubules were also bundled or they enclosed rings in their lumen. The findings clearly demonstrate the potency of Ca2+ to induce different polymorphic assemblies with additional protofilament associations, not realized in microtubules.
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Affiliation(s)
- W Vater
- Institute of Molecular Biotechnology, Research Group of Electron Microscopy and Molecular Cytology, Jena, Germany
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14
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Abstract
The main advantage to using frozen semen in any breeding program is faster genetic gain for the inherited trait desired. Milk production of dairy cows doubled (from 26,000 to 52,000 kg of milk/cow per year) between 1950 and 1980, because the dairy industry was using semen only from bulls with the greatest genetic potential for milk production. This genetic gain could have been achieved without the use of frozen semen; however, the time required to achieve that same genetic progress would have been lengthened exceedingly. Fertility rates using frozen stallion spermatozoa are not equal to that of fresh semen, but with careful management of both the stallion and the mare fertility rates of 40% to 60% can be achieved for a single mare reproductive cycle and fertility rates of 60% to 75% during the course of a breeding season can be expected for a number of stallions. Because pregnancy rates have increased and because many breed registries now condone the use of frozen stallion semen, more people in the equine industry are using frozen semen. It has been the attempt of this article to make the practitioner aware of some of the problems that can occur when processing, freezing, storing, and using frozen semen, and how to control those problems. The practitioner also should be aware that there is large variation in semen quality from stallions, and that spermatozoa from some of the problem stallions can be improved by altering a "standard protocol," but that semen from some stallions will not cryopreserve effectively, regardless of the efforts put forth.
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Affiliation(s)
- J K Graham
- Department of Physiology, Colorado State University, Fort Collins, USA
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15
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Vater W, Fritzsche W, Schaper A, Böhm KJ, Unger E, Jovin TM. Scanning force microscopy of microtubules and polymorphic tubulin assemblies in air and in liquid. J Cell Sci 1995; 108 ( Pt 3):1063-9. [PMID: 7622594 DOI: 10.1242/jcs.108.3.1063] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We have investigated microtubules (MTs) and polymorphic assemblies, formed in vitro from isolated microtubule protein, by scanning force microscopy (SFM) in air and in liquid. Immobilization of MTs was achieved by placing a drop of the assembly solution on a polylysine-coated coverslip. After washing with taxol and air drying, the characteristic microtubular fibrous morphology appeared in the SFM. The MTs formed a network similar to that obtained by transmission electron microscopy (TEM). A height of approximately 9.5 nm for dried MTs was computed from the surface topography. Glutaraldehyde fixation of the MTs yielded higher structures (approximately 14 nm), which swelled to approximately 20 nm after rehydration, a value close to the MT diameter of approximately 25 nm determined from TEM images of ultrathin sections. The protofilament pattern of the MTs and surface attached MT-associated proteins were not apparent from SFM, although the height along the long axis of the MTs appeared slightly modulated. In addition to MTs, various polymorphic tubulin assemblies including ribbons, hoops and double-walled MTs were visualized by SFM.
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Affiliation(s)
- W Vater
- Institut für Molekulare Biotechnologie, Forschungsgruppe Elektronenmikroskopie und Molekulare Zytologie, Jena, Germany
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16
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Abstract
Empirical approaches to semen cryopreservation have resulted in the production of young in a broad range of species. However, acceptable levels of fertility in most domestic animal species has not been achieved. In this review, an attempt has been made to describe the complexity of the sperm plasma membrane and the many steps in a cryopreservation procedure where membrane perturbations can occur. Improvement in sperm cryopreservation procedures will require a careful consideration of the complexity of the sperm plasma membrane, the interaction of its components and the influence of cooling, freezing and thawing on these interactions.
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Affiliation(s)
- J E Parks
- Department of Animal Science, Cornell University Ithaca, NY 14853 USA
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17
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Abstract
This review summarizes recent data for cryopreservation of poultry sperm and data establishing the contraceptive effect of glycerol. Successful cryopreservation protocols for bovine sperm are compared to the requirements for rooster sperm, with emphasis on glycerol-induced alterations in avian reproductive systems. It has been shown that molar concentrations of glycerol can affect (a) physical features of the cytoplasm (cytoplasmic organization and viscosity), (b) permeability and stability of the membrane bilayer(s), and (c) noncovalent attachment of proteins to the sperm surface. Perturbing effects of glycerol on sperm metabolism and the essentiality of maintaining bioenergetic balance during the temperature changes associated with any cryopreservation protocol are discussed. Emphasis is placed on the processes in avian reproduction that may be altered by interactions with glycerol. Finally, we discuss the potential value of using available genetic models (lines of roosters differing in the capacity of their sperm to survive a freeze-thaw cycle) to clarify and overcome damage to poultry sperm induced by cryopreservation.
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Affiliation(s)
- R H Hammerstedt
- Biochemistry Program, Pennsylvania State University, University Park 16802
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Schilstra MJ, Bayley PM, Martin SR. The effect of solution composition on microtubule dynamic instability. Biochem J 1991; 277 ( Pt 3):839-47. [PMID: 1678598 PMCID: PMC1151320 DOI: 10.1042/bj2770839] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The exchange of tubulin dimer into steady-state microtubules was studied over a range of solution conditions, in order to assess the effects of various common buffer components on the dynamic instability of microtubules. In comparison with standard buffer conditions (100 mM-Pipes buffer, pH 6.5, containing 0.1 mM-EGTA, 1.8 mM-MgC12 and 1 M-glycerol), the rate and extent of exchange, and thus of dynamic instability, are suppressed by increasing the concentration of glycerol above 2 M. Exchange is enhanced by the addition of further Mg2+ (up to 17 mM) or by the addition of Ca2+ (up to 0.4 mM). Phosphate ion (150 mM) has relatively little effect on the dynamic behaviour of microtubules, as judged by the exchange method. The findings are interpreted within the framework of the Lateral Cap model for microtubule dynamic instability, in terms of the effects of these changes on the intrinsic rate constants of the system. By contrast, the extent of tubulin exchange depends selectively on the value of the dissociation rate constant for tubulin-GDP. A decrease in the extent of exchange, and hence in dynamic activity, is associated with a decreased value for this rate constant, and vice versa. The results also show good agreement of predictions of the model in treating the observed variations in the dynamic properties of individual microtubules, induced by different solution conditions.
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Affiliation(s)
- M J Schilstra
- Division of Physical Biochemistry, National Institute for Medical Research, London, U.K
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Minotti AM, Barlow SB, Cabral F. Resistance to antimitotic drugs in Chinese hamster ovary cells correlates with changes in the level of polymerized tubulin. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(19)67891-9] [Citation(s) in RCA: 168] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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Unger E, Böhm KJ, Vater W. Structural diversity and dynamics of microtubules and polymorphic tubulin assemblies. ELECTRON MICROSCOPY REVIEWS 1990; 3:355-95. [PMID: 2103347 DOI: 10.1016/0892-0354(90)90007-f] [Citation(s) in RCA: 60] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Tubulin, the main protein of microtubules (MTs), has the potency of forming a variety of other assembly products in vitro: rings, ring-crystals, C- and S-shaped ribbons, 10 nm fibres, hoops, sheets, heaped sheets, MT doublets, MT triplets, double-wall MTs, microtubules, curled ribbons, and paracrystals. The supramolecular subunits of all of them are the protofilaments which might be arranged either parallel to the axis (e.g., in MTs, ribbons) or curved (e.g., in hoops, microtubules). There is strong evidence that in the second case the protofilaments have an inside-out orientation compared to MTs. All assembly products mentioned are described structurally and their relevance to the in vivo situation is considered. Moreover, MTs and the other assemblies undergo permanent changes. These dynamics occurring in both individual assemblies and assembly populations are discussed from the structural point of view.
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Affiliation(s)
- E Unger
- Academy of Sciences of the G.D.R., Central Institute of Microbiology and Experimental Therapy, Jena
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Wandosell F, Villanueva N, Serrano L, Avila J. Analysis of drug-tubulin interaction by trypsin cleavage: comparison for colchicine, podophyllotoxin, griseofulvin, vinblastine and taxol. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. B, COMPARATIVE BIOCHEMISTRY 1986; 85:635-8. [PMID: 2878792 DOI: 10.1016/0305-0491(86)90060-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Trypsin preferentially cleaves the alpha subunit of depolymerized tubulin or vinblastine induced aggregates (in which longitudinal interactions between tubulin molecules could take place). No cleavage was found for tubulin polymerized into microtubules (containing lateral and longitudinal tubulin interactions), in the presence of taxol. In the presence of colchicine or podophyllotoxin the alpha subunit was partially protected from proteolytic digestion. Trypsin digestion pattern varied upon the addition of different concentrations of griseofulvin. At the higher concentration used, in which microtubules assembly was inhibited, both tubulin subunits were cleaved.
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Bayley PM, Butler FM, Clark DC, Manser EJ, Martin SR. The assembly of microtubule protein in vitro. The kinetic role in microtubule elongation of oligomeric fragments containing microtubule-associated proteins. Biochem J 1985; 227:439-55. [PMID: 4004773 PMCID: PMC1144863 DOI: 10.1042/bj2270439] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The kinetics of assembly were studied for bovine and pig microtubule protein in vitro over a range of conditions of pH, temperature, nucleotide and protein concentration. The kinetics are in general biphasic with two major processes of similar amplitude but separated in rate by one order of magnitude. Rates and amplitudes are complex functions of solution conditions. The rates of the fast phase and the slow phase attain limiting values as a function of increasing protein concentration, and are more stringently limited at pH 6.5 than pH 6.95. Such behaviour indicates that mechanisms other than the condensation polymerization of tubulin dimer become rate-limiting at higher protein concentration. The constancy of the wavelength-dependence of light-scattering and ultrastructural criteria indicate that microtubules of normal morphology are formed in both phases of the assembly process. Electrophoretic analysis of assembling microtubule protein shows that MAP- (microtubule-associated-protein-)rich microtubules are formed during the fast phase. The rate of dissociation of oligomeric species on dilution of microtubule protein closely parallels the fast-phase rate in magnitude and temperature-dependence. We propose that the rate of this process constitutes an upper limit to the rate of the fast phase of assembly. The kinetics of redistribution of MAPs from MAP-rich microtubules may be a factor limiting the slow-phase rate. A working model is derived for the self-assembly of microtubule protein incorporating the dissociation and redistribution mechanisms that impose upper limits to the rates of assembly attainable by bimolecular addition reactions. Key roles are assigned to MAP-containing fragments in both phases of microtubule elongation. Variations in kinetic behaviour with solution conditions are inferred to derive from the nature and properties of fragments formed from oligomeric species after the rapid temperature jump. The model accounts for the limiting rate behaviour and indicates experimental criteria to be applied in evaluating the relative contributions of alternative pathways.
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Böhm KJ, Vater W, Fenske H, Unger E. Effect of microtubule-associated proteins on the protofilament number of microtubules assembled in vitro. BIOCHIMICA ET BIOPHYSICA ACTA 1984; 800:119-26. [PMID: 6743686 DOI: 10.1016/0304-4165(84)90049-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
In order to demonstrate the effect of microtubule-associated proteins on the protofilament number of microtubules, we used different systems of microtubule formation in vitro in which these proteins are either functionally eliminated (by DNA or glycerol) or absent (purified tubulin). The results obtained by electron microscopy of ultrathin-sectioned material indicate that under standard conditions in the presence of microtubule-associated proteins microtubules are formed consisting predominantly of 14 protofilaments. In cases of deficiency of microtubule-associated proteins, the mean value of the protofilament number is lower, and the protofilament number within the microtubule population varies remarkably. On the other hand, the action of microtubule-associated proteins is enhanced by histones resulting in increased protofilament numbers. A model is proposed illustrating that the quality and the quantity of microtubule-associated proteins bound to microtubules determine the curvature between the protofilaments and restrict the variety of their binding angles. In this way the microtubule-associated proteins may be regarded as an important factor in determining the structural fidelity of microtubules.
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Keates RA. Griseofulvin at low concentration inhibits the rate of microtubule polymerization in vitro. Biochem Biophys Res Commun 1981; 102:746-52. [PMID: 7306181 DOI: 10.1016/s0006-291x(81)80195-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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