Berlin 2015 – scientific programme

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BP: Fachverband Biologische Physik

BP 16: Posters: Cell adhesion, mechanics and migration

BP 16.29: Poster

Monday, March 16, 2015, 17:30–19:30, Poster A

Characterization of intracellular phagosome transport — •Steve Keller, Konrad Berghoff, and Holger Kress — Department of Physics, University of Bayreuth, Bayreuth, Germany

As one of the key processes during the immune response, phagocytosis of bacteria plays a significant role in the mammalian immune system. During phagocytosis invaders larger than a few hundred nanometers are internalized by macrophages followed by lysosome fusion and digestion. A key part of this maturation process is the phagosomal transport from the cell membrane to the perinuclear region. While on average, phagosomes are transported to this region, individual phagosomes undergo complex motion which frequently consists of directed transport with interjacent phases of putative random motion. Up to now it is largely unknown what determines these high phagosome to phagosome variations of the individual transport paths. Natural differences between these phagosomes in vivo are their size and shape as well as the position, where the first contact to the cell membrane and the subsequent engulfment occurs. To investigate these naturally occurring phagosome variations systematically, we move IgG-coupled polystyrene beads with different diameters to well-defined positions at the cell membrane of J774 macrophages by using holographic optical tweezers. By tracking the bead motion during and after internalisation, we are able to characterize the transport of individual phagosomes. Preliminary results indicate that larger particles move faster and in a more persistent way towards the perinuclear region whereas smaller particles move slower with more interjacent phases of random motion.