title: Myosin II Activity Softens Cells in Suspension.
abstract: The cellular cytoskeleton is crucial for many cellular functions such as cell motility and wound healing, as well as other processes that require shape change or force generation. Actin is one cytoskeleton component that regulates cell mechanics. Important properties driving this regulation include the amount of actin, its level of cross-linking, and its coordination with the activity of specific molecular motors like myosin. While studies investigating the contribution of myosin activity to cell mechanics have been performed on cells attached to a substrate, we investigated mechanical properties of cells in suspension. To do this, we used multiple probes for cell mechanics including a microfluidic optical stretcher, a microfluidic microcirculation mimetic, and real-time deformability cytometry. We found that nonadherent blood cells, cells arrested in mitosis, and naturally adherent cells brought into suspension, stiffen and become more solidlike upon myosin inhibition across multiple timescales (milliseconds to minutes). Our results hold across several pharmacological and genetic perturbations targeting myosin. Our findings suggest that myosin II activity contributes to increased whole-cell compliance and fluidity. This finding is contrary to what has been reported for cells attached to a substrate, which stiffen via active myosin driven prestress. Our results establish the importance of myosin II as an active component in modulating suspended cell mechanics, with a functional role distinctly different from that for substrate-adhered cells.
authors.affiliation: Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge, United Kingdom; Biotechnology Center, Technische Universität Dresden, Dresden, Germany.
authors.forename: Chii J
authors.initials: CJ
authors.lastname: Chan
authors.affiliation: Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge, United Kingdom; Biotechnology Center, Technische Universität Dresden, Dresden, Germany.
authors.forename: Andrew E
authors.initials: AE
authors.lastname: Ekpenyong
authors.affiliation: Biotechnology Center, Technische Universität Dresden, Dresden, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Golfier
authors.affiliation: Biotechnology Center, Technische Universität Dresden, Dresden, Germany.
authors.forename: Wenhong
authors.initials: W
authors.lastname: Li
authors.affiliation: Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge, United Kingdom; Wellcome Trust/Medical Research Council Stem Cell Institute, Cambridge, United Kingdom.
authors.forename: Kevin J
authors.initials: KJ
authors.lastname: Chalut
authors.affiliation: Biotechnology Center, Technische Universität Dresden, Dresden, Germany.
authors.forename: Oliver
authors.initials: O
authors.lastname: Otto
authors.affiliation: Institute of Complex Systems, Forschungszentrum Jülich, Jülich, Germany.
authors.forename: Jens
authors.initials: J
authors.lastname: Elgeti
authors.affiliation: Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge, United Kingdom; Biotechnology Center, Technische Universität Dresden, Dresden, Germany.
authors.forename: Jochen
authors.initials: J
authors.lastname: Guck
authors.affiliation: Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge, United Kingdom; Department of Physics, Saarland University, Saarbrücken, Germany. Electronic address: f.lautenschlaeger@physik.uni-saarland.de.
authors.forename: Franziska
authors.initials: F
authors.lastname: Lautenschläger
mesh_terms: D016475:3T3 Cells; D008841:Actin Cytoskeleton / Q000737:chemistry / Q000378:metabolism; D000818:Animals; D002448:Cell Adhesion; D002462:Cell Membrane / Q000378:metabolism* / Q000648:ultrastructure; D004548:Elasticity; D006367:HeLa Cells; D006801:Humans; D051379:Mice; D044085:Microfluidics; D024462:Myosin Type II / Q000737:chemistry / Q000378:metabolism*
chemical_list: D024462:Myosin Type II