1 research outputs found
Distribution of PDLIM1 at Actin-Rich Structures Generated by Invasive and Adherent Bacterial Pathogens
The enteric bacterial pathogens Listeria monocytogenes (Listeria) and enteropathogenic Escherichia coli (EPEC) remodel the eukaryotic actin cytoskeleton during their disease processes. Listeria generate slender actinârich comet/rocket tails to move intracellularly, and later, fingerâlike membrane protrusions to spread amongst host cells. EPEC remain extracellular, but generate similar actinârich membranous protrusions (termed pedestals) to move atop the host epithelia. These structures are crucial for disease as diarrheal (and systemic) infections are significantly abrogated during infections with mutant strains that are unable to generate the structures. The current repertoire of host components enriched within these structures is vast and diverse. In this protein catalog, we and others have found that host actin crosslinkers, such as palladin and αâactininâ1, are routinely exploited. To expand on this list, we set out to investigate the distribution of PDLIM1, a scaffolding protein and binding partner of palladin and αâactininâ1, during bacterial infections. We show that PDLIM1 localizes to the site of initial Listeria entry into cells. Following this, PDLIM1 localizes to actin filament clouds surrounding immotile bacteria, and then colocalizes with actin once the comet/rocket tails are generated. Unlike palladin or αâactininâ1, PDLIM1 is maintained within the actinârich core of membrane protrusions. Conversely, αâactininâ1, but not PDLIM1 (or palladin), is enriched at the membrane invagination that internalizes the Listeriaâcontaining membrane protrusion. We also show that PDLIM1 is a component of the EPEC pedestal core and that its recruitment is dependent on the bacterial effector Tir. Our findings highlight PDLIM1 as another protein present within pathogenâinduced actinârich structures