Journal Article

Membrane mediated motor kinetics in microtubule gliding assays

Quint, David A., Lopes, Joseph, Xu, Melissa, Chapman, Dail E., Gopinathan, Ajay, Hirst, Linda S.

2019

Overview

Motor-based transport mechanisms are critical for a wide range of eukaryotic cell functions, including the transport of vesicle cargos over long distances. Our understanding of the factors that control and regulate motors when bound to a lipid substrate is however incomplete. We used microtubule gliding assays on a lipid bilayer substrate to investigate the role of membrane diffusion in kinesin-1 on/off binding kinetics and thereby transport velocity. Fluorescence imaging experiments demonstrate motor clustering on single microtubules due to membrane diffusion in the absence of ATP, followed by rapid ATP-induced dissociation during gliding. Our experimental data combined with analytical modeling show that the on/off binding kinetics of the motors are impacted by diffusion and, as a consequence, both the effective binding and unbinding rates for motors are much lower than the expected bare rates. Our results suggest that motor diffusion in the membrane can play a significant role in transport by impacting motor kinetics and can therefore function as a regulator of intracellular transport dynamics.

• Publisher: Nature Publishing Group UK,Nature Publishing Group
• Subject: 631/57/2270 / 631/57/2272/1590 / 639/766/747 / Adenosine Triphosphate - metabolism / Animals / Diffusion / Experiments / Fluorescence Recovery After Photobleaching / Gliding / Humanities and Social Sciences / Image Processing, Computer-Assisted / Kinesin / Kinesin - chemistry / Kinesin - metabolism / Kinetics / Lipid bilayers / Lipid Bilayers - chemistry / Lipid Bilayers - metabolism / Lipids / Membranes / Microscopy, Fluorescence / Microtubules / Microtubules - chemistry / Microtubules - metabolism / multidisciplinary / Protein Binding / Proteins / Science / Science (multidisciplinary) / Swine