2019/07/24 by Niv Ierushalmi, Ierushalmi, Niv, Maya Malik-Garbi +12 · 2 citations
Biochemistry, Genetics and Molecular Biology · Chemistry · Engineering · Physics and Astronomy · #Actin #Biological Physics (physics.bio-ph) #Biology #Biophysics #Cell #Cell biology #Cell division #Cellular Mechanics and Interactions #Chemistry #Contraction (grammar) #Cytoplasm #FOS: Physical sciences #Fluid Dynamics and Heat Transfer #Micro and Nano Robotics #Motility #Physics #Symmetry breaking #Xenopus #physics.bio-ph
paper · pdf · doi:10.48550/arxiv.1907.10642
arxiv created 2019/07/24 · openalex publication_date 2019/07/24 · arxiv updated 2019/07/26 · openalex created_date 2022/07/28 · openalex updated_date 2026/07/28
Centering and decentering of cellular components is essential for internal organization of cells and their ability to perform basic cellular functions such as division and motility. How cells achieve proper localization of their components is still not well-understood, especially in large cells such as oocytes. Here, we study actin-based positioning mechanisms in artificial cells with persistently contracting actomyosin networks, generated by encapsulating cytoplasmic Xenopus egg extracts into cell-sized water-in-oil droplets. We observe size-dependent localization of the contraction center, with a symmetric configuration in larger cells and a polar one in smaller cells. In the symmetric state, the contraction center is actively centered, via a hydrodynamic mechanism based on Darcy friction between the contracting network and the surrounding cytoplasm. During symmetry breaking, transient attachments to the cell boundary drive the contraction center to a polar location near the droplet boundary. Our findings demonstrate a robust, yet tunable, mechanism for subcellular localization.