Role of the Putative Histidine Kinase BP1092 in Virulence Regulation and Intracellular Survival.

persists inside host cells, and virulence factors are crucial for intracellular adaptation. The regulation of virulence factor transcription primarily occurs through the modulation of the two-component system (TCS) known as BvgAS. However, additional regulatory systems have emerged as potential contributors to virulence regulation. Here, we investigate the impact of BP1092, a putative TCS histidine kinase that shows increased levels after bacterial internalization by macrophages, on proteome adaptation under nonmodulating (Bvg+) and modulating (Bvg-) conditions. Using mass spectrometry, we compare wild-type (wt), a BP1092-deficient mutant (Δ), and a Δ-complemented strain under both conditions. We find an altered abundance of 10 proteins, including five virulence factors. Specifically, under nonmodulating conditions, the mutant strain showed decreased levels of FhaB, FhaS, and Cya compared to the wt. Conversely, under modulating conditions, the mutant strain exhibited reduced levels of BvgA and BvgS compared to those of the wt. Functional assays further revealed that the deletion of BP1092 gene impaired ability to survive within human macrophage THP-1 cells. Taken together, our findings allow us to propose BP1092 as a novel player involved in the intricate regulation of virulence factors and thus in adaptation to the intracellular environment. The data have been deposited to the ProteomeXchange Consortium via the PRIDE partner repository with the data set identifier PXD041940.