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bioRxiv · 10.1101/2022.05.04.490675

Actin nano-architecture of phagocytic podosomes

Herron, J. C.·Hu, S.·Watanabe, T.·Nogueira, A. T.·Liu, B.·Kern, M.·Arron, J.·Taylor, A.·Pablo, M.·Chew, T.-L.·Elston, T. C.·Hahn, K. M.
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Abstract

Podosomes are actin-enriched adhesion structures important for multiple cellular processes, including migration, bone remodeling, and phagocytosis. Here, we characterized the structure and organization of phagocytic podosomes using interferometric photoactivated localization microscopy (iPALM), a super-resolution microscopy technique capable of 15-20 nm resolution, together with structured illumination microscopy (SIM) and localization-based superresolution microscopy. Phagocytic podosomes were observed during frustrated phagocytosis, a model in which cells attempt to engulf micro-patterned IgG antibodies. For circular patterns, this resulted in regular arrays of podosomes with well-defined geometry. Using persistent homology, we developed a pipeline for semi-automatic identification and measurement of podosome features. These studies revealed an "hourglass" shape of the podosome actin core, a protruding "knob" at the bottom of the core, and two actin networks extending from the core. Additionally, the distributions of paxillin, talin, myosin II, -actinin, cortactin, and microtubules relative to actin were characterized.

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Herron, J. C., Hu, S., Watanabe, T., Nogueira, A. T., Liu, B., Kern, M., Arron, J., Taylor, A., Pablo, M., Chew, T.-L., Elston, T. C., Hahn, K. M.. 2022-05-05. Actin nano-architecture of phagocytic podosomes. https://doi.org/10.1101/2022.05.04.490675

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