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Binding, Tubulin leads to Disruption, Microtubule dynamics
Key Event Relationship Overview
AOPs Referencing Relationship
|AOP Name||Adjacency||Weight of Evidence||Quantitative Understanding||Point of Contact||Author Status||OECD Status|
|Chemical binding to tubulin in oocytes leading to aneuploid offspring||adjacent||High||Cataia Ives (send email)||Open for citation & comment||EAGMST Under Review|
Life Stage Applicability
|All life stages||High|
Key Event Relationship Description
Chemicals that bind to tubulin on colchicine or vinca domain directly interfere with the addition of new tubulin dimers to the microtubules. The result of this process is a net loss of microtubules (i.e., microtubule depolymerization).
Evidence Collection Strategy
Evidence Supporting this KER
Strong based on biological plausibility and available empirical data. There is no uncertainty.
The weight of evidence for this KER is strong. The majority of work for this KER has been derived from research on the prototypical chemical colchicine; however, information is also available for other chemicals such as podophillotoxin, vinblastin, and colcemid. There is high biological plausibility for the binding of colchicine to tubulin leading to microtubule depolymerization, which is one of the most studied chemical interactions with a biological molecule [Margolis and Wilson, 1977; Garland, 1978; Ravelli et al., 2004]. There is extensive understanding of the chemistry of both the binding interactions and the subsequent interference with microtubule dynamics. Depolymerization following colchicine exposure has been measured in frog and mouse eggs, and in human cells, including eggs, in culture [Salmon et al., 1984; Wilson et al., 1984; Ibanez et al., 2003; Liu et al., 2010].
Uncertainties and Inconsistencies
No apparent uncertainties or inconsistencies. This KER is biologically plausible and broadly accepted. Indeed, in vitro assays to measure tubulin depolymerization are well standardized and represent the gold standard to determine whether a chemical is binding to tubulin.
Known modulating factors
Microtubules assembled in vitro contain several minor protein components that have been referred to as microtubule-associated proteins (MAPs). Several of these proteins are believed to play a role in the microtubule assembly process [Kakiu & Sato, 2016]. MAPs have been shown to inhibit colchicine binding to tubulin in a competitive manner. In contrast, Mg2+, which also induces microtubule assembly in vitro, had no effect on colchicine binding to tubulin [Nunez J et al. 1978].
Microtubule assembly is inhibited by approximately 50% when half of the tubulin dimers are bound by colchicine [Margolis et al., 1980], and a concentration of 2.5 μM of colchicine is needed to inhibit microtubule polymerization by 50% [Zavala et al., 1980].
Colchicine binds slowly to tubulin, in contrast to Combretastatin A4, which binds in a relatively fast, temperature-dependent manner. The rate of Colchicine binding has a rate constant of ~102 M-1 s-1 as determined by an isotopic labeling technique [Gaarland D.L. 1978]. Hovever, colchicine dissociates from tubulin over 100 times slower than combretastatin A-4, with a half.life of 405 min at 37 °C, compared to 3.6 min of CA4 [Lin et al. 1989].
Known Feedforward/Feedback loops influencing this KER
To our knowledge, there are no feedback loops influencing this KER.
Domain of Applicability
This KER has been demonstrated in multiple species including sea urchins, frogs, mice, rats, cows, and human cells in culture.
Bhattacharyya B, Panda D, Gupta S, Banerjee M. 2008. Anti-mitotic activity of colchicine and the structural basis for its interaction with tubulin. Med Res Rev 28:155-183.
Brunner M, Albertini S, Würgler FE. 1991. Effects of 10 known or suspected spindle poisons in the in vitro porcine brain tubulin assembly assay. Mutagen 6:65-70.
Garland DL. 1978. Kinetics and mechanism of colchicine binding to tubulin: Evidence for ligand-induced conformational change. Biochemistry 17:4266–4272.
Hastie SB. 1991. Interaction of colchicine with tubulin. Pharmacol Ther 51:377-401.
Kakui Y, Sato M. 2016. Differentiating the roles of microtubule-associated proteins at meiotic kinetochores during chromosome segregation. Chromosoma 125:309-320.
Ibanez E, Albertini DF, Overstrom EW. 2003. Demecolcine-induced oocyte enucleation for somatic cell cloning: Coordination between cell-cycle egress, kinetics of cortical cytoskeletal interactions, and second polar body extrusion. Biol Reprod 68:1249–1258.
Linn CM, Ho HH, Pettit GR, Hamel E. 1989. Antimitotic natural products combretastatin A-4 ad combretastatin A: studies on the mechanism of their inhibition of the binding of colchicine to tubulin. Biochemistry 28:6984-6991.
Liu S, Li Y, Feng HL, Yan JH, Li M, Ma SY, Chen ZJ. 2010. Dynamic modulation of cytoskeleton during in vitro maturation in human oocytes. Am J Obstet Gynecol 203:151.e151–157.
Nunez J, Fellous A, Francon J, Lennon AN. 1978. Competitive inhibition of colchicine binding to tubulin by microtubule-associated proteins. Proc Natl Acad Sci USA 76:86-90.
Margolis RL, Wilson L. 1977. Addition of colchicine-tubulin complex to microtubule ends: the mechanism of substoichiometric colchicine poisoning. Proc Natl Acad Sci U S A 74:3466-3470.
Margolis RL, Rauch CT, Wilson L. 1980. Mechanism of colchicine-dimer addition to microtubule polymerization mechanism. Biochemistry 19:5550-5557.
Pettit GR, Toki B, Herald DL, Verdier-Pinard P, Boyd MR, Hamel E, Pettit RK. 1998. Antineoplastic agents. 379. Synthesis of phenstatin phosphate. J Med Chem 41:1688-1695.
Ravelli RB, Gigant B, Curmi PA, Jourdain I, Lachkar S, Sobel A, Knossow M. 2004. Insight into tubulin regulation from a complex with colchicine and a stathmin-like domain. Nature 428:198–202.
Salmon ED, McKeel M, Hays T. 1984. Rapid rate of tubulin dissociation from microtubules in the mitotic spindle in vivo measured by blocking polymerization with colchicine. J Cell Biol 99:1066–1075.
Wallin M, Hartley-Asp B. 1993. Effects of potential aneuploidy inducing agents on microtubule assembly in vitro. Mutat Res 287:17-22.
Wilson L, Miller HP, Pfeffer TA, Sullivan KF, Detrich HW,3. 1984. Colchicine-binding activity distinguishes sea urchin egg and outer doublet tubulins. J Cell Biol 99:37–41