title: "Cargo-mooring" as an operating principle for molecular motors.
abstract: Navigating through an ever-changing and unsteady environment, and utilizing chemical energy, molecular motors transport the cell׳s crucial components, such as organelles and vesicles filled with neurotransmitter. They generate force and pull cargo, as they literally walk along the polymeric tracks, e.g. microtubules. What we suggest in this paper is that the motor protein is not really pulling its load. The load is subject to diffusion and the motor may be doing little else than rectifying the fluctuations, i.e. ratcheting the load׳s diffusion. Below we present a detailed model to show how such ratcheting can quantitatively account for observed data. The consequence of such a mechanism is the dependence of the transport׳s speed and efficacy not only on the motor, but also on the cargo (especially its size) and on the environment (i.e. its viscosity and structure). Current experimental works rarely provide this type of information for in vivo studies. We suggest that even small differences between assays can impact the outcome. Our results agree with those obtained in wet laboratories and provide novel insight in a molecular motor׳s functioning.
authors: M. Smoluchowski Institute of Physics Jagiellonian University, Kraków, Poland; Unit of Pharmacoepidemiology and Pharmacoeconomics, Faculty of Pharmacy, Jagiellonian University Medical College, Kraków, Poland. Electronic address: bartek.lisowski@uj.edu.pl.
authors: Bartosz
authors: B
authors: Lisowski
authors: M. Smoluchowski Institute of Physics Jagiellonian University, Kraków, Poland; AGH University of Science and Technology, Institute of Automatics, Al. Mickiewicza 30, 30-059, Krakow, Poland.
authors: Łukasz
authors: Ł
authors: Kuśmierz
authors: M. Smoluchowski Institute of Physics Jagiellonian University, Kraków, Poland.
authors: Michał
authors: M
authors: Żabicki
authors: Department of Physics, East Carolina University, Greenville, NC 27858, USA.
authors: Martin
authors: M
authors: Bier
mesh_terms: D000818:Animals; D001665:Binding Sites; D001692:Biological Transport; D002021:Buffers; D003599:Cytoskeleton / Q000378:metabolism; D004058:Diffusion; D016547:Kinesins / Q000502:physiology*; D008870:Microtubules / Q000378:metabolism; D008954:Models, Biological; D020409:Molecular Motor Proteins / Q000378:metabolism*; D009218:Myosins / Q000378:metabolism; D018377:Neurotransmitter Agents; D052898:Optical Tweezers; D011336:Probability; D013314:Stress, Mechanical; D014783:Viscosity
chemical_list: D002021:Buffers; D020409:Molecular Motor Proteins; D018377:Neurotransmitter Agents; D009218:Myosins; D016547:Kinesins
keywords: 87.10.-e; 87.15.Vv; 87.16.Nn; 87.18.-h; Diffusion; Intracellular transport; Kinesin; Molecular motors