Effect of temperature and pressure on polymerisation equilibrium of neuronal microtubules

Engelborghs, Yves; Heremans, Karel; Maeyer, L. C. M. De; Hoebeke, Johan

doi:10.1038/259686a0

Cited by 69 publications

(29 citation statements)

References 15 publications

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“…Hypo-osmotic shock causes a dramatic but transient tubulin depolymerization, which is rapidly reversed. Tubulin has been reported to be depolymerized by increased pressure (Engelborghs et al, 1976;Larsen et al, 2000), and the time course of tubulin disruption observed here, that is, disruption within 2 minutes and recovery by 4 minutes, is certainly compatible with a direct linkage to the transient pressure increase inside the cell. Other studies commenting on the effect of osmotic shock on microtubules have suggested that perturbation of microtubule kinetics either has no effect on, or inhibits, the RVD (Downey et al, 1995;Edmonds and Koenig, 1990;Shen et al, 1999;Zhang et al, 1997), and that hypotonicity may stabilize microtubules and stimulate tubulin synthesis (Haussinger et al, 1994).…”

Section: Discussionsupporting

confidence: 65%

Keratin mutations of epidermolysis bullosa simplex alter the kinetics of stress response to osmotic shock

D’Alessandro

Reverter

Morley

et al. 2002

Journal of Cell Science

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pathways were induced faster, as seen by early activation of JNK, ATF-2 and c-Jun. We demonstrate that the speed of a cell's response to hypotonic stress, by activation of the SAPK/JNK pathway, is correlated with the clinical severity of the mutation carried. The response to hypo-osmotic shock constitutes a discriminating stress assay to distinguish between the effects of different keratin mutations and is a potentially valuable tool in developing therapeutic strategies for keratin-based skin fragility disorders.

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Section: Discussionsupporting

confidence: 65%

Keratin mutations of epidermolysis bullosa simplex alter the kinetics of stress response to osmotic shock

D’Alessandro

Reverter

Morley

et al. 2002

Journal of Cell Science

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“…The increase in pressure produced by centrifugation at 100000 x g in the conditions described in Fig. 1 has been shown not to cause depolymerization of microtubules formed at 37 "C [16,17].…”

Section: Separation Of Polymerized From Non-polymerized Tubulin In Crmentioning

confidence: 99%

Quantification and Properties of Tubulin Polymerization in Crude Brain Extracts and Preparations of Microtubular and Purified Tubulin

Sandoval

Cuatrecasas

1978

Eur J Biochem

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Removal of assembled tubulin by centrifugation, followed by measurement in the supernatant of the residual colchicine binding capacity of the non-polymerized, non-precipitable tubulin, is a sensitive and reliable method of measuring tubulin polymerization. This method can be used in both crude and purified preparations of brain tubulin and allows the molar quantification of the total, polymerized and non-polymerized tubulin species in each sample.Only 40-50% of the total tubulin present in crude adult brain extracts is capable of polymerizing when incubated with GTP. The percentage of tubulin polymerizing with GTP is slightly higher in crude foetal brain extracts than in the adult. tubulin which can aggregate or polymerize (e.g. actin, filamin, neurofilament subunits), and preparations of purified tubulin contain high-molecular-weight proteins which by forming filaments [6] may also interfere with the quantification of tubulin polymerization by these methods.Measurement of the amount of tubulin which does not polymerize under given conditions can be an effective method of quantifying tubulin assembly in vitro, provided that the assembled tubulin is initially separated from other tubulin forms (dimers, rings, aggregates) and that a specific and exact method is available for the molar quantification of tubulin.The present study describes the selective removal of assembled tubulin by centrifugation from preparations

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“…The recent results of Margolis and Wilson (5), which showed that the pathway for microtubule assembly is not the pathway for microtubule disassembly, raise further questions concerning reversibility. A point of additional confusion is the numerous and varied enthalpies which have been reported from studies using van't Hoff analysis (6)(7)(8)(9) and direct calorimetry (10)(11)(12).…”

mentioning

confidence: 99%

Observation of an exothermic process associated with the in vitro polymerization of brain tubulin.

Berkowitz¹,

Veliçelebi²,

Sutherland³

et al. 1980

Proc. Natl. Acad. Sci. U.S.A.

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The polymerization of tubulin has been studied with a high-sensitivity differential scannin microcalorimeter, with results which indicate that microtu ule assembly can proceed via one or possibly two exothermic reactions. The amount of heat evolution has been found to be far in excess of GTP hydrolysis. The heat liberated has been observed to depend strongly upon the exact experimental conditions, varying from many hundreds of kilocalories per mole of tubulin dimer when dilute tubulin solutions are heated rapidly to a few kilocalories per mole of tubulin dimer when concentrated tubulin solutions are heated slowly. The results are tentatively interpreted in terms of the existence of at least two pathways or the ormation of energetically distinct polymers. These findings indicate the importance of kinetic factors in studying tubulin polymerization.Microtubules are a class of organelles that appear to be present in all eukaryotic cells. These structures are thought to function as a cytoskeleton (to maintain the shape and form of cells) or in the transport of various macromolecules and supramolecular structures [for a recent review of these organelles see Dustin (1)]. Because the temporal and spatial control of the assembly and disassembly of microtubules is believed to be a key factor in cellular function, an understanding of the mechanism or mechanisms involved in this process is of great importance.Since the discovery of the conditions necessary for the in vitro assembly of cytoplasmic microtubules (2), a considerable amount of biochemical and biophysical work has been directed toward unraveling the mechanism of the polymerization and depolymerization of tubulin, the major protein subunit of microtubules, which has a molecular weight of 110,000 (3). Although various models have been proposed [which are summarized in a recent review by Kirschner (4)], there is no general agreement as to their validity. In all these models it has been assumed that the assembly of microtubules is reversible, and that its temperature-dependent behavior shows it to be an endothermic reaction. However, if GTP hydrolysis is indeed coupled to this process, a question arises as to its thermodynamic reversibility. The recent results of Margolis and Wilson (5), which showed that the pathway for microtubule assembly is not the pathway for microtubule disassembly, raise further questions concerning reversibility.

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Effect of temperature and pressure on polymerisation equilibrium of neuronal microtubules

Cited by 69 publications

References 15 publications

Keratin mutations of epidermolysis bullosa simplex alter the kinetics of stress response to osmotic shock

Keratin mutations of epidermolysis bullosa simplex alter the kinetics of stress response to osmotic shock

Quantification and Properties of Tubulin Polymerization in Crude Brain Extracts and Preparations of Microtubular and Purified Tubulin

Observation of an exothermic process associated with the in vitro polymerization of brain tubulin.

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