How to clear a pathogen during inflammation: switching from phagocytosis to macropinocytosis through coronin 1 phosphorylation

The processes that allow phagocytes to eliminate pathogenic microbes under inflammatory conditions remain incompletely understood. Recent work has implicated coronin 1 in the modulation of endocytic traffic upon macrophage activation. While in resting macrophages, uptake occurs largely through receptor-mediated phagocytosis, inflammatory stimuli such as interferon-and tumor necrosis factor-were found to activate macropinocytic uptake of cargo through phosphatidyl-3 kinase activation in a coronin 1-dependent manner. In this commentary we will briefly describe these recently published results, and discuss how this inducible pathway may serve to clear the inflammatory site from large amounts of infectious material and couple pathogen clearance to a proper activation of immune responses.