title: Steady-state EB cap size fluctuations are determined by stochastic microtubule growth and maturation.
abstract: Growing microtubules are protected from depolymerization by the presence of a GTP or GDP/Pi cap. End-binding proteins of the EB1 family bind to the stabilizing cap, allowing monitoring of its size in real time. The cap size has been shown to correlate with instantaneous microtubule stability. Here we have quantitatively characterized the properties of cap size fluctuations during steady-state growth and have developed a theory predicting their timescale and amplitude from the kinetics of microtubule growth and cap maturation. In contrast to growth speed fluctuations, cap size fluctuations show a characteristic timescale, which is defined by the lifetime of the cap sites. Growth fluctuations affect the amplitude of cap size fluctuations; however, cap size does not affect growth speed, indicating that microtubules are far from instability during most of their time of growth. Our theory provides the basis for a quantitative understanding of microtubule stability fluctuations during steady-state growth.
authors.affiliation: The Francis Crick Institute, London NW1 1AT, United Kingdom.|Centre for Mathematics and Physics in Life Sciences and Experimental Biology, University College London, London WC1E 6BT, United Kingdom.
authors.forename: Jamie
authors.initials: J
authors.lastname: Rickman
authors.affiliation: The Francis Crick Institute, London NW1 1AT, United Kingdom.
authors.forename: Christian
authors.initials: C
authors.lastname: Duellberg
authors.affiliation: The Francis Crick Institute, London NW1 1AT, United Kingdom.
authors.forename: Nicholas I
authors.initials: NI
authors.lastname: Cade
authors.affiliation: Centre for Mathematics and Physics in Life Sciences and Experimental Biology, University College London, London WC1E 6BT, United Kingdom.
authors.forename: Lewis D
authors.initials: LD
authors.lastname: Griffin
authors.affiliation: The Francis Crick Institute, London NW1 1AT, United Kingdom; Thomas.Surrey@crick.ac.uk.
authors.forename: Thomas
authors.initials: T
authors.lastname: Surrey
mesh_terms: D006153:Guanosine Diphosphate / Q000378:metabolism; D006160:Guanosine Triphosphate / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D008870:Microtubules / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding; D014404:Tubulin / Q000737:chemistry / Q000378:metabolism
chemical_list: D014404:Tubulin; D006153:Guanosine Diphosphate; D006160:Guanosine Triphosphate
keywords: EB1; GTP cap; biochemical network; dynamic instability; microtubules