The actin comet guides the way: How<scp>Listeria</scp>actin subversion has impacted cell biology, infection biology and structural biology

International audience; The discovery of the role of ActA to polymerise actin at one pole of Listeria monocytogenes represents a key event in the field of cellular microbiology. It uncovered much more than the molecular principle behind actin-based motility of Listeria within the cytosol of infected cells, and it changed the way how actin dynamics could be studied and eventually understood. The ActA discovery took place at a time when cell biology, biochemistry and microbiology came together in a very fruitful fashion. Here, we provide an overview of the science that took place around this event. Then, we outline the wide array of research fields that have been impacted by this finding. This ranges from structural and biophysical investigations on actin and its dynamics, the role of actin polymerisation during infection with different pathogens, to actin-dynamics during various pathologies. Like a comet in the sky, Pascale Cossart&#39;s work on ActA has inspired and will inspire generations of (life) scientists.