The postdoc will work on an ERC Starting Grant-funded project focused on the molecular mechanisms of actin-based motility in intracellular bacterial pathogens. The project investigates how Shigella and Listeria hijack the host actin cytoskeleton to move inside infected cells. These bacteria use specialized surface proteins, IcsA and ActA, to recruit host actin-regulatory proteins and generate actin comet tails that propel the bacteria through the cytoplasm. The main goal of the postdoc project will be to understand how this process is regulated at the molecular and structural level.
The postdoc will establish and use in vitro reconstitution assays for actin-based motility, combining engineered bacterial systems displaying IcsA or ActA with purified host actin-regulatory proteins. Using fluorescence microscopy, the postdoc will quantify actin-tail formation, bacterial movement, filament elongation, and the effects of regulatory host factors on these processes. Candidate regulators will be selected based on preliminary mass-spectrometry data and literature, and their effects on actin-based motility will be tested biochemically and microscopically. A central part of the project will be structural analysis by cryo-electron tomography and, where applicable, single-particle cryo-EM. The postdoc will prepare vitrified samples of bacteria undergoing actin-based motility, collect and process cryo-ET data, and determine how bacterial effectors, host regulatory proteins and actin filaments are organized within actin comet tails. This work will make use of the in- house Talos Arctica electron microscope, which will be upgraded with a new camera through the ERC-funded investment.
Overall, the postdoc will contribute to a mechanistic model explaining how bacterial pathogens control the host actin cytoskeleton to drive intracellular motility.
