Hydrodynamic flow caused by active transport along cytoskeletal elements

¹  Van 't Hoff Institute for Molecular Sciences (HIMS), Universiteit van Amsterdam - Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands
²  Departament de Física Fonamental, Universitat de Barcelona - Carrer Martí i Franqués 1, 08028-Barcelona, Spain
³  Wageningen University, Laboratory of Plant Cell Biology - Arboretumlaan 4, 6703 BD Wageningen, The Netherlands

Received: 9 July 2006
Accepted: 12 February 2007

Abstract

We develop a simple lattice model to describe the hydrodynamic influence of active mass transport along bio-filaments on freely diffusing mass in the cell. To quantify the overall mass transport we include Brownian motion, excluded volume interactions, active transport along the filaments, and hydrodynamic interactions. The model shows that the hydrodynamic forces induced by molecular motors attached to the filaments give rise to a non-negligible flux close to the filament. This additional flux appears to have two effects. Depending on the degree of filament occupation it can exert a sufficiently large influence on unbound motors and cargo to modify their transport and also regulate the flux of motors bound to the filament. We expect such a mechanism is important in situations found in plant cells, where directional transport spans the entire cell. In particular, it can explain the cytoplasmic streaming observed in plant cells.