2015/10/31 by Wylie W. Ahmed, Wylie Ahmed, Etienne Fodor +10 · 2 citations
Biochemistry, Genetics and Molecular Biology · Chemistry · Physics and Astronomy · #Biology #Biophysics #Cellular Mechanics and Interactions #Chemistry #Classical mechanics #Diffusion #In vivo #Kinetics #Materials science #Mesoscopic physics #Micro and Nano Robotics #Microtubule and mitosis dynamics #Molecular motor #Myosin #Nanotechnology #Physics #Thermodynamics #cond-mat.soft #physics.bio-ph #q-bio.QM #q-bio.SC
paper · pdf · doi:10.1016/j.bpj.2018.02.009
published as Biophysical Journal 114,7, 1667(2018) · 20 pages, 4 figures, see ancillary files for Supplementary Materials, * equally contributing authors
arxiv created 2018/02/08 · openalex publication_date 2018/04/01 · arxiv updated 2018/04/12 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
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, however, 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 τ∼ 300 μs resulting in an average force of F ∼ 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.