TPL-2 kinase induces phagosome acidification to promote macrophage killing of Staphylococcus aureus

ABSTRACT: Tumor Progression Locus 2 (TPL-2) kinase mediates Toll-like Receptor (TLR) activation of ERK1/2 and p38-alpha MAP kinases in myeloid cells to modulate expression of key cytokines in innate immunity. This study identified a novel MAP kinase-independent regulatory function for TPL-2 in phagosome maturation, an essential process for killing of phagocytosed bacteria. TPL-2 catalytic activity was demonstrated to induce phagosome acidification and proteolysis in primary mouse and human macrophages following uptake of latex beads. Mass spectrometry analysis revealed that blocking TPL-2 catalytic activity significantly altered the protein composition of phagosomes, particularly reducing the abundance of V-ATPase proton pump subunits. Furthermore, TPL-2 was shown to stimulate the phosphorylation of DMXL1, a critical regulator of V-ATPases, to induce phagosome acidification. Consistent with these results, TPL-2 catalytic activity was required for phagosome acidification, activation of phagosome acid-sensitive cathepsins and the efficient killing of Staphylococcus aureus following phagocytic uptake by macrophages. These results indicate that TPL-2 controls the innate immune response of macrophages to bacteria via MAP kinase regulation of gene expression and V-ATPase induction of phagosome maturation.

INSTRUMENT(S):

ORGANISM(S): Mus Musculus (mouse)

TISSUE(S): Bone Marrow, Macrophage

SUBMITTER: Matthias Trost  

LAB HEAD: Matthias Trost

PROVIDER: PXD020401 | Pride | 2021-02-11

REPOSITORIES: Pride