title: Microtubule aging probed by microfluidics-assisted tubulin washout.
abstract: Microtubules switch stochastically between phases of growth and shrinkage. The molecular mechanism responsible for the end of a growth phase, an event called catastrophe, is still not understood. The probability for a catastrophe to occur increases with microtubule age, putting constraints on the possible molecular mechanism of catastrophe induction. Here we used microfluidics-assisted fast tubulin washout experiments to induce microtubule depolymerization in a controlled manner at different times after the start of growth. We found that aging can also be observed in this assay, providing valuable new constraints against which theoretical models of catastrophe induction can be tested. We found that the data can be quantitatively well explained by a simple kinetic threshold model that assumes an age-dependent broadening of the protective cap at the microtubule end as a result of an evolving tapered end structure; this leads to a decrease of the cap density and its stability. This analysis suggests an intuitive picture of the role of morphological changes of the protective cap for the age dependence of microtubule stability.
authors.affiliation: Lincoln's Inn Fields Laboratory, Francis Crick Institute, London WC2A 3LY, United Kingdom.
authors.forename: Christian
authors.initials: C
authors.lastname: Duellberg
authors.affiliation: Lincoln's Inn Fields Laboratory, Francis Crick Institute, London WC2A 3LY, United Kingdom.
authors.forename: Nicholas Ian
authors.initials: NI
authors.lastname: Cade
authors.affiliation: Lincoln's Inn Fields Laboratory, Francis Crick Institute, London WC2A 3LY, United Kingdom thomas.surrey@crick.ac.uk.
authors.forename: Thomas
authors.initials: T
authors.lastname: Surrey
mesh_terms: D051339:Actin Depolymerizing Factors; D000367:Age Factors; D000818:Animals; D006160:Guanosine Triphosphate / Q000737:chemistry; D007700:Kinetics; D044085:Microfluidics / Q000379:methods*; D008870:Microtubules / Q000378:metabolism*; D008954:Models, Biological; D008962:Models, Theoretical; D013552:Swine; D014404:Tubulin / Q000378:metabolism*
chemical_list: D051339:Actin Depolymerizing Factors; D014404:Tubulin; D006160:Guanosine Triphosphate