@article{HsuKrekhovTarantolaetal.2019,
  author    = {Hsu, H. F. and Krekhov, Andrey and Tarantola, Marco and Beta, Carsten and Bodenschatz, Eberhardt},
  title     = {Interplay between myosin II and actin dynamics in chemotactic amoeba},
  series = {New journal of physics : the open-access journal for physics},
  volume    = {21},
  journal   = {New journal of physics : the open-access journal for physics},
  number    = {11},
  publisher = {IOP Publ. Ltd.},
  address   = {Bristol},
  issn      = {1367-2630},
  doi       = {10.1088/1367-2630/ab5822},
  pages     = {15},
  year      = {2019},
  abstract  = {The actin cytoskeleton and its response to external chemical stimuli is fundamental to the mechano-biology of eukaryotic cells and their functions. One of the key players that governs the dynamics of the actin network is the motor protein myosin II. Based on a phase space embedding we have identified from experiments three phases in the cytoskeletal dynamics of starved Dictyostelium discoideum in response to a precisely controlled chemotactic stimulation. In the first two phases the dynamics of actin and myosin II in the cortex is uncoupled, while in the third phase the time scale for the recovery of cortical actin is determined by the myosin II dynamics. We report a theoretical model that captures the experimental observations quantitatively. The model predicts an increase in the optimal response time of actin with decreasing myosin II-actin coupling strength highlighting the role of myosin II in the robust control of cell contraction.},
  language  = {en}
}
@misc{BarbosaPfannesAnielskiGerhardtetal.2013,
  author    = {Barbosa Pfannes, Eva Katharina and Anielski, Alexander and Gerhardt, Matthias and Beta, Carsten},
  title     = {Intracellular photoactivation of caged cGMP induces myosin II and actin responses in motile cells},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-94984},
  pages     = {1456 -- 1463},
  year      = {2013},
  abstract  = {Cyclic GMP (cGMP) is a ubiquitous second messenger in eukaryotic cells. It is assumed to regulate the association of myosin II with the cytoskeleton of motile cells. When cells of the social amoeba Dictyostelium discoideum are exposed to chemoattractants or to increased osmotic stress, intracellular cGMP levels rise, preceding the accumulation of myosin II in the cell cortex. To directly investigate the impact of intracellular cGMP on cytoskeletal dynamics in a living cell, we released cGMP inside the cell by laser-induced photo-cleavage of a caged precursor. With this approach, we could directly show in a live cell experiment that an increase in intracellular cGMP indeed induces myosin II to accumulate in the cortex. Unexpectedly, we observed for the first time that also the amount of filamentous actin in the cell cortex increases upon a rise in the cGMP concentration, independently of cAMP receptor activation and signaling. We discuss our results in the light of recent work on the cGMP signaling pathway and suggest possible links between cGMP signaling and the actin system.},
  language  = {en}
}
@misc{AlonsoStangeBeta2018,
  author    = {Alonso, Sergio and Stange, Maike and Beta, Carsten},
  title     = {Modeling random crawling, membrane deformation and intracellular polarity of motile amoeboid cells},
  series = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe},
  journal   = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe},
  number    = {1014},
  issn      = {1866-8372},
  doi       = {10.25932/publishup-45974},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-459745},
  pages     = {24},
  year      = {2018},
  abstract  = {Amoeboid movement is one of the most widespread forms of cell motility that plays a key role in numerous biological contexts. While many aspects of this process are well investigated, the large cell-to-cell variability in the motile characteristics of an otherwise uniform population remains an open question that was largely ignored by previous models. In this article, we present a mathematical model of amoeboid motility that combines noisy bistable kinetics with a dynamic phase field for the cell shape. To capture cell-to-cell variability, we introduce a single parameter for tuning the balance between polarity formation and intracellular noise. We compare numerical simulations of our model to experiments with the social amoeba Dictyostelium discoideum. Despite the simple structure of our model, we found close agreement with the experimental results for the center-of-mass motion as well as for the evolution of the cell shape and the overall intracellular patterns. We thus conjecture that the building blocks of our model capture essential features of amoeboid motility and may serve as a starting point for more detailed descriptions of cell motion in chemical gradients and confined environments.},
  language  = {en}
}