title: Bidirectional membrane tube dynamics driven by nonprocessive motors.
abstract: In cells, membrane tubes are extracted by molecular motors. Although individual motors cannot provide enough force to pull a tube, clusters of such motors can. Here, we investigate, using a minimal in vitro model system, how the tube pulling process depends on fundamental properties of the motor species involved. Previously, it has been shown that processive motors can pull tubes by dynamic association at the tube tip. We demonstrate that, remarkably, nonprocessive motors can also cooperatively extract tubes. Moreover, the tubes pulled by nonprocessive motors exhibit rich dynamics as compared to those pulled by their processive counterparts. We report distinct phases of persistent growth, retraction, and an intermediate regime characterized by highly dynamic switching between the two. We interpret the different phases in the context of a single-species model. The model assumes only a simple motor clustering mechanism along the length of the entire tube and the presence of a length-dependent tube tension. The resulting dynamic distribution of motor clusters acts as both a velocity and distance regulator for the tube. We show the switching phase to be an attractor of the dynamics of this model, suggesting that the switching observed experimentally is a robust characteristic of nonprocessive motors. A similar system could regulate in vivo biological membrane networks.
authors.affiliation: Physics of Life Processes, Leiden Institute of Physics, Leiden University, Niels Bohrweg 2, 2333 CA Leiden, The Netherlands.
authors.forename: Paige M
authors.initials: PM
authors.lastname: Shaklee
authors.forename: Timon
authors.initials: T
authors.lastname: Idema
authors.forename: Gerbrand
authors.initials: G
authors.lastname: Koster
authors.forename: Cornelis
authors.initials: C
authors.lastname: Storm
authors.forename: Thomas
authors.initials: T
authors.lastname: Schmidt
authors.forename: Marileen
authors.initials: M
authors.lastname: Dogterom
mesh_terms: D000818:Animals; D003198:Computer Simulation; D029721:Drosophila Proteins / Q000378:metabolism; D004331:Drosophila melanogaster / Q000378:metabolism; D016547:Kinesins / Q000378:metabolism; D008954:Models, Biological; D020409:Molecular Motor Proteins / Q000378:metabolism*; D053835:Unilamellar Liposomes / Q000378:metabolism*
chemical_list: D029721:Drosophila Proteins; D020409:Molecular Motor Proteins; D053835:Unilamellar Liposomes; C066696:ncd protein, Drosophila; D016547:Kinesins