References of "Betz, Timo"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailActive Mechanics Reveal Molecular-Scale Force Kinetics in Living Oocytes
Ahmed, Wylie W.; Fodor, Etienne UL; Almonacid, Maria et al

in BIOPHYSICAL JOURNAL (2018), 114(7), 1667-1679

Active diffusion of intracellular components is emerging as an important process in cell biology. This process is mediated by complex assemblies of molecular motors and cytoskeletal filaments that drive ... [more ▼]

Active diffusion of intracellular components is emerging as an important process in cell biology. This process is mediated by complex assemblies of molecular motors and cytoskeletal filaments that drive force generation in the cytoplasm and facilitate enhanced motion. The kinetics of molecular motors have been precisely characterized in vitro by single molecule approaches, but their in vivo behavior remains elusive. Here we study the active diffusion of vesicles in mouse oocytes, where this process plays a key role in nuclear positioning during development, and combine an experimental and theoretical framework to extract molecular-scale force kinetics (force, power stroke, and velocity) of the in vivo active process. Assuming a single dominant process, we find that the nonequilibrium activity induces rapid kicks of duration tau similar to 300 mu s resulting in an average force of F similar to 0.4 pN on vesicles in in vivo oocytes, remarkably similar to the kinetics of in vitro myosin-V. Our results reveal that measuring in vivo active fluctuations allows extraction of the molecular-scale activity in agreement with single-molecule studies and demonstrates a mesoscopic framework to access force kinetics. [less ▲]

Detailed reference viewed: 25 (0 UL)
Full Text
Peer Reviewed
See detailActive cell mechanics: Measurement and theory
Ahmed, Wylie W.; Fodor, Etienne UL; Betz, Timo

in BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH (2015), 1853(11, B, SI), 3083-3094

Living cells are active mechanical systems that are able to generate forces. Their structure and shape are primarily determined by biopolymer filaments and molecular motors that form the cytoskeleton ... [more ▼]

Living cells are active mechanical systems that are able to generate forces. Their structure and shape are primarily determined by biopolymer filaments and molecular motors that form the cytoskeleton. Active force generation requires constant consumption of energy to maintain the nonequilibrium activity to drive organization and transport processes necessary for their function. To understand this activity it is necessary to develop new approaches to probe the underlying physical processes. Active cell mechanics incorporates active molecular-scale force generation into the traditional framework of mechanics of materials. This review highlights recent experimental and theoretical developments towards understanding active cell mechanics. We focus primarily on intracellular mechanical measurements and theoretical advances utilizing the Langevin framework. These developing approaches allow a quantitative understanding of nonequilibrium mechanical activity in living cells. This article is part of a Special Issue entitled: Mechanobiology. (C) 2015 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license [less ▲]

Detailed reference viewed: 80 (0 UL)