TY - JOUR A1 - Huber, Florian A1 - Käs, Josef A1 - Stuhrmann, Björn T1 - Growing actin networks form lamellipodium and lamellum by self-assembly JF - Biophysical Journal N2 - Many different cell types are able to migrate by formation of a thin actin-based cytoskeletal extension. Recently, it became evident that this extension consists of two distinct substructures, designated lamellipodium and lamellum, which differ significantly in their kinetic and kinematic properties as well as their biochemical composition. We developed a stochastic two-dimensional computer simulation that includes chemical reaction kinetics, G-actin diffusion, and filament transport to investigate the formation of growing actin networks in migrating cells. Model parameters were chosen based on experimental data or theoretical considerations. In this work, we demonstrate the system's ability to form two distinct networks by self-organization. We found a characteristic transition in mean filament length as well as a distinct maximum in depolymerization flux, both within the first 1-2 microm. The separation into two distinct substructures was found to be extremely robust with respect to initial conditions and variation of model parameters. We quantitatively investigated the complex interplay between ADF/cofilin and tropomyosin and propose a plausible mechanism that leads to spatial separation of, respectively, ADF/cofilin- or tropomyosin-dominated compartments. Tropomyosin was found to play an important role in stabilizing the lamellar actin network. Furthermore, the influence of filament severing and annealing on the network properties is explored, and simulation data are compared to existing experimental data. KW - Open Archive Y1 - 2008 UR - http://www.ncbi.nlm.nih.gov/pubmed/18708450 U6 - https://doi.org/10.1529/biophysj.108.134817 SN - 1542-0086 VL - 95 IS - 12 SP - 5508 EP - 5523 PB - Biophysical Society ER - TY - JOUR A1 - Migueles, Jairo H. A1 - Rowlands, Alex V. A1 - Huber, Florian A1 - Sabia, Séverine A1 - van Hees, Vincent T. T1 - GGIR: A Research Community–Driven Open Source R Package for Generating Physical Activity and Sleep Outcomes From Multi-Day Raw Accelerometer Data JF - Journal for the Measurement of Physical Behaviour Y1 - 2019 U6 - https://doi.org/10.1123/jmpb.2018-0063 SN - 2575-6605 VL - 2 IS - 3 SP - 188 EP - 196 PB - Human Kinetics ER -