LPS ubiquitylation and innate immunity

Our ability to fight infections relies not on the capacity of our professional immune system to defend our body but also on the skills of individual cells to defend themselves. How professional immune cells contribute to innate and acquired immunity has long been studied. Much less is known about how regular body cells defend themselves against pathogens, a process known as cell-autonomous immunity. Inspired by the ability of unicellular organisms to rely exclusively on cell-autonomous defences, we investigate how mammalian cells protect their interior against bacterial invasion.

Our recent work has revealed a novel principle of cell-autonomous immunity. We discovered that mammalian cells convert cytosol-invading bacteria into pro-inflammatory and anti-bacterial signalling platforms by depositing host proteins into polyvalent arrays at bacterial surfaces. Examples include the ubiquitylation of bacterial LPS (the first known instance of ubiquitylation targeting a non-proteinaceous substrate) (Otten Nature 2021) and the deposition of GBPs, a family of interferon-induced GTPases, which are essential for anti-bacterial autophagy and caspase-4—dependent pyroptotic cell death, respectively (Wandel Nat Immunol 2020, Falcon Mol Cell 2019, Noad Nat Microbiol 2017, Wandel, Cell Host Microbe 2017).

A position for an enthusiastic PhD student interested in host-pathogen interactions is available. Work will focus on the transformation of bacterial surfaces into signalling platforms. Potential projects include the functional and structural characterization of LPS ubiquitylation by RNF213, the investigation how GBPs detect bacteria, and the identification of novel anti-bacterial effector mechanisms triggered by polyvalent protein coats on bacterial surfaces.