title: Entropic forces drive contraction of cytoskeletal networks.
abstract: The cytoskeleton is a network of interconnected protein filaments, which provide a three-dimensional scaffold for cells. Remodeling of the cytoskeleton is important for key cellular processes, such as cell motility, division, or morphogenesis. This remodeling is traditionally considered to be driven exclusively by processes consuming chemical energy, such as the dynamics of the filaments or the action of molecular motors. Here, we review two mechanisms of cytoskeletal network remodeling that are independent of the consumption of chemical energy. In both cases directed motion of overlapping filaments is driven by entropic forces, which arise from harnessing thermal energy present in solution. Entropic forces are induced either by macromolecular crowding agents or by diffusible crosslinkers confined to the regions where filaments overlap. Both mechanisms increase filament overlap length and lead to the contraction of filament networks. These force-generating mechanisms, together with the chemical energy-dependent mechanisms, need to be considered for the comprehensive quantitative picture of the remodeling of cytoskeletal networks in cells.
authors.affiliation: B CUBE - Center for Molecular Bioengineering, Technische Universität Dresden, Dresden, Germany.|Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany.
authors.forename: Marcus
authors.initials: M
authors.lastname: Braun
authors.affiliation: B CUBE - Center for Molecular Bioengineering, Technische Universität Dresden, Dresden, Germany.|Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany.|Institute of Biotechnology CAS, BIOCEV Center, Vestec, Czech Republic.
authors.forename: Zdenek
authors.initials: Z
authors.lastname: Lansky
authors.affiliation: Martin Fisher School of Physics, Brandeis University, Waltham, MA, USA.
authors.forename: Feodor
authors.initials: F
authors.lastname: Hilitski
authors.affiliation: Martin Fisher School of Physics, Brandeis University, Waltham, MA, USA.
authors.forename: Zvonimir
authors.initials: Z
authors.lastname: Dogic
authors.affiliation: B CUBE - Center for Molecular Bioengineering, Technische Universität Dresden, Dresden, Germany.|Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Diez
mesh_terms: D001696:Biomechanical Phenomena; D002455:Cell Division; D002465:Cell Movement; D003599:Cytoskeleton / Q000378:metabolism* / Q000648:ultrastructure; D019277:Entropy; D005057:Eukaryotic Cells / Q000378:metabolism / Q000648:ultrastructure; D006801:Humans; D008869:Microtubule-Associated Proteins / Q000378:metabolism*; D008870:Microtubules / Q000378:metabolism* / Q000648:ultrastructure; D020409:Molecular Motor Proteins / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000378:metabolism / Q000648:ultrastructure; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*
chemical_list: C472767:Ase1 protein, S cerevisiae; D008869:Microtubule-Associated Proteins; D020409:Molecular Motor Proteins; D029701:Saccharomyces cerevisiae Proteins
keywords: cytoskeleton; depletion forces; entropic forces; entropy; filament crosslinkers; force generation; molecular motors