TY - JOUR
T1 - Active Mechanics Reveal Molecular-Scale Force Kinetics in Living Oocytes
AU - Ahmed, Wylie W.
AU - Fodor, Etienne
AU - Almonacid, Maria
AU - Bussonnier, Matthias
AU - Verlhac, Marie-Helene
AU - Gov, Nir
AU - Visco, Paolo
AU - van Wijland, Frederic
AU - Betz, Timo
N1 - We thank Jacques Prost, Cécile Sykes, Julie Plastino, and Jean-Francois Joanny for helpful discussions. We thank Melina Schuh (MPI Göttingen) for providing the MyoVb tail plasmid, Clément Campillo for help with synthetic vesicle experiments, and Amanda Remorino for critical reading of the manuscript. W.W.A. is a recipient of postdoctoral fellowships from La Fondation Pierre-Gilles de Gennes and Marie Curie Actions ( FP7-MC-IIF-624887 ). M.A. is a recipient of postdoctoral fellowships from the Ligue Nationale contre le Cancer and from the Labex MemoLife. M.B. is a recipient of an AXA PhD fellowship. N.S.G. gratefully acknowledges funding from the Israel Science Foundation ( 580/12 ). M.-H.V. gratefully acknowledges the ANR (ANR-DIVACEN N°14-CE11 ) and the FRM Label ( DEQ20150331758 ). T.B. was supported by the French Agence Nationale de la Recherche ( ANR-11-JSV5-0002 ) and the Deutsche Forschungsgemeinschaft as well as by a Cells-in-Motion Cluster of Excellence grant ( EXC 1003 – CiM ) from the University of Münster , Germany. Author Contributions W.W.A. and T.B. conceived and supervised the project. W.W.A., M.B., M.A., and M.-H.V. performed experiments. É.F., N.S.G., P.V., and F.v.W. developed the theoretical model and performed simulations. W.W.A. and É.F. integrated experiment and theory. All authors contributed to data analysis and/or interpretation. W.W.A. and T.B. wrote the manuscript, which was seen and corrected by all authors.
PY - 2018/4/10
Y1 - 2018/4/10
N2 - 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 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.
AB - 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 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.
UR - http://www.scopus.com/inward/record.url?scp=85044998451&partnerID=8YFLogxK
U2 - https://doi.org/10.1016/j.bpj.2018.02.009
DO - https://doi.org/10.1016/j.bpj.2018.02.009
M3 - مقالة
C2 - 29642036
SN - 0006-3495
VL - 114
SP - 1667
EP - 1679
JO - Biophysical Journal
JF - Biophysical Journal
IS - 7
ER -