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BP: Fachverband Biologische Physik

BP 33: Cytoskeletal Filaments II

BP 33.3: Talk

Thursday, March 15, 2018, 15:30–15:45, H 1028

Size-dependent phagosomal transport depends on microtubules, actin filaments and associated motors — •Steve Keller, Konrad Berghoff, and Holger Kress — University of Bayreuth, Bayreuth, Germany

The internalization and intracellular degradation of pathogens by macrophages is an essential part of the mammalian immune response. The associated intracellular transport of the phagosome from the cell periphery to the perinuclear region is crucial for the phagosome maturation. To date biochemical factors are known to influence the fate of phagosomes. Here we show that the phagosomal transport is also strongly influenced by the size of the phagosomes and that this size-dependent transport depends on microtubules, actin filaments and associated motors. We found that large phagosomes are transported very persistently to the nucleus with almost no centrifugal motion, whereas small phagosomes show strong bidirectional transport. Our investigation of the molecular basis of this size-dependent transport suggests that dynein motors and the intracellular distribution of microtubules strongly influence the centripetal transport of large phagosomes. Additionally, our findings indicate that actin filament-associated motors and the distribution of actin filaments strongly influence the bidirectional transport of small phagosomes. Our findings suggest that a simple size-dependent cellular sorting mechanism might exist that supports inward transport of large phagocytosed bacteria for facilitating their digestion and that simultaneously supports outward transport of small bacterial fragments for example for antigen presentation.