Regensburg 2022 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 13: Cytoskeleton

BP 13.1: Hauptvortrag

Mittwoch, 7. September 2022, 09:30–10:00, H15

Cortex mechanics - how subtle modifications matter — •Andreas Janshoff — Institute of Physical Chemistry, Tammannstr. 6, University of Goettingen, 37077 Goettingen

Cell cortices are responsible for the resilience and morphological dynamics of cells. Measuring their mechanical properties is impeded by contributions from other filament types, organelles, and the crowded cytoplasm. Therefore, we established two routes to examine its essential features using i) a bottom-up approach to create artificial minimal actin cortices (MACs) and b) by extracting cortices from living cells. Apical cell membranes of confluent MDCK II cells as well as MACs were deposited or formed on porous substrates and either locally deformed using an atomic force microscope setup or explored by microrheology techniques. Force cycles could be described with a time-dependent area compressibility modulus obeying the same power law as employed for whole cells. We found that subtle modifications such as the composition of the plasma membrane and origin of actin, i.e., the chosen isoform or its posttranslational modification are important for the dynamics and mechanics of the cortex. We found that the presence of phosphatidylserine in the inner leaflet of the plasma membranes is crucial for cortex contractility and efficient binding of F-actin to the membrane.