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BP: Fachverband Biologische Physik

BP 24: Poster B: Active Biological Matter, Cell Mechanics, Systems Biology, Computational Biophysics, etc.

BP 24.27: Poster

Tuesday, March 23, 2021, 16:00–18:30, BPp

A matter of size: Understanding size-dependent organelle transport in cells — •Simon Wieland^1,2, David Gitschier¹, Marius M. Kaiser¹, Christina Steininger¹, Wolfgang Groß¹, Adam G. Hendricks³, and Holger Kress¹ — ¹Biological Physics Group, University of Bayreuth, Bayreuth — ²Animal Ecology I, University of Bayreuth, Bayreuth — ³Department of Bioengineering, McGill University, Montreal

Intracellular transport of organelles is essential for numerous cellular processes, including phagocytosis. Earlier findings indicate that the persistence of organelle transport during phagocytosis strongly depends on cargo size. To understand this behavior on a molecular level, we systematically quantified the size-dependence of phagosomal transport forces using magnetic tweezers. We found that transport forces increase with organelle size. With a simple geometrical model taking the distribution of microtubules around the organelles into account, we explain the scaling behavior of the transport forces. Our findings indicate that intracellular organelles displace microtubules from their original positions, leading to an increased microtubule density at the organelles surface, and thus an increased number of binding possibilities for molecular motors. Additionally, we performed immunofluorescence experiments on isolated phagosomes, allowing us to identify and estimate the relative number of molecular motors on the organelles. Quantifying the size-dependence of phagosomal transport can lead to a deeper understanding of intracellular organelle transport and the dynamics of interactions between molecular motors and the cytoskeleton.