SKM 2023 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 8: Cell Mechanics I
BP 8.6: Vortrag
Dienstag, 28. März 2023, 11:15–11:30, BAR Schö
Force generation in human blood platelets by filamentous actomyosin structures — •Anna Zelena1, Johannes Blumberg2, Ulrich S. Schwarz2, and Sarah Köster1 — 1Institute for X-Ray Physics, Georg-August-University of Göttingen, Germany — 2Institute for Theoretical Physics, University of Heidelberg, Germany
Blood platelets are central elements of the blood clotting response after wounding. Upon vessel damage, they adhere to the surrounding matrix of the vessel and contract the emerging blood clot, thus helping to restore normal blood flow. The blood clotting function of platelets has been shown to be directly connected to their mechanics and cytoskeletal organization. The reorganization of the platelet cytoskeleton during spreading occurs within minutes and leads to the formation of contractile actomyosin bundles, but it is not known how this structure formation corresponds to force generation. In this study, we combine fluorescence imaging of the actin structures with traction force measurements in a time-resolved manner. We find that force generation is localized in few hotspots, which spatially align very closely with the visualized end points of the fibrous actin structures and do not change much with time. Moreover we show that force generation is a very robust mechanism independent of changes in the amount of added thrombin in solution or fibrinogen coverage on the substrate, suggesting that force generation after platelet activation is a threshold phenomenon that ensures reliable blood clot contraction in diverse environments.