'Switch-like' transition from random to directed motility of microtubules by a yeast dynein

Processive transport by multiple molecular motors that step stochastically, requires a form of mechanical coupling. In a quantitative microtubule (MT) gliding assay with yeast cytoplasmic dynein, we investigate the nature of this coupling by examining the effect of MT length and motor density on tra...

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Bibliographic Details
Published inbioRxiv
Main Authors Jain, Kunalika, Khetan, Neha, Athale, Chaitanya A
Format Paper
LanguageEnglish
Published Cold Spring Harbor Cold Spring Harbor Laboratory Press 28.08.2017
Subjects
Dynein
Gliding
Mechanical properties
Microtubules
Mitosis
Motility
Stochasticity
Velocity
Yeast
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Summary:Processive transport by multiple molecular motors that step stochastically, requires a form of mechanical coupling. In a quantitative microtubule (MT) gliding assay with yeast cytoplasmic dynein, we investigate the nature of this coupling by examining the effect of MT length and motor density on transport. We find speed and velocity have a length dependence for low motor numbers, but are independent of MT length for high motor densities. The dependence of speed, velocity and degree of randomness of MT transport is best understood when evaluated in terms of the numbers of motors bound to a filament. A model of collective transport of MTs, based on stochastic stepping and asymmetric detachment rates, reproduces the experimental trends of decreasing diffusivity with increasing number of motors. Additionally, the model predicts a 'switch-like' increase in directionality of MT transport above a threshold number of motors. Such a rapid transition from random to directed motility with increasing numbers of yeast dyneins, could play a role in vivo during mitosis in the 'search and orientation' of the Saccharomyces cerevisiae nucleus.
DOI:10.1101/181404