Strength and stability of active ligand-receptor bonds: a microtubule attached to a wall by molecular motor tethers

Abstract

We develop a stochastic kinetic model of a pre-formed attachment of a mictrotuble (MT) with a cell cortex, in which the MT is tethered to the cell by a group of active motor proteins. Such an attachment is a particularly unique case of ligand-receptor bonds: The MT ligand changes its length (and thus binding sites) with time by polymerization-depolymerization kinetics, while multiple motor receptors tend to walk actively along the MT length. These processes, combined with force-mediated unbinding of the motors, result in an elaborate behavior of the MT connection to the cell cortex. We present results for the strength and lifetime of the system through the well-established force-clamp and force-ramp protocols when external tension is applied to the MT. The simulation results reveal that the MT-cell attachment behaves as a catch-bond or slip-bond depending on system parameters. We provide analytical approximations of the lifetime and discuss implications of our results on in-vitro experiments.

arXiv commentThoroughly revised model, data, figures, text, bibliography and authorship

References in corpus (10)

• Tug-of-war as a cooperative mechanism for bidirectional cargo transport by molecular motors
• Stochastic mechano-chemical kinetics of molecular motors: a multidisciplinary enterprise from a physicist's perspective
• Ligand-Receptor Interactions
• Active diffusion of motor particles
• Depinning of semiflexible polymers in (1+1) dimensions
• Novel steady state of a microtubule assembly in a confined geometry
• Forced desorption of semiflexible polymers, adsorbed and driven by molecular motors
• Feedback Mechanism for Microtubule Length Regulation by Stathmin Gradients
• Distribution of lifetimes of kinetochore-microtubule attachments: interplay of energy landscape, molecular motors and microtubule (de-)polymerization
• Molecular force spectroscopy of kinetochore-microtubule attachment {\it in silico}: Mechanical signatures of an unusual catch bond and collective effects