The secreted tyrosine phosphatase PtpA promotes Staphylococcus aureus survival in RAW 264.7 macrophages through decrease of the SUMOylation host response

Staphylococcus aureus is a human pathogen that is extremely adaptable and is the cause of a variety of nosocomial and community-acquired infectious diseases. During infection, S. aureus is able to affect the host cell in many ways to enable its own multiplication, spread, and evasion of the host immune defense. One of the mechanisms utilized by S. aureus to survive is to inhibit the SUMOylation of host proteins in order to increase its intracellular survival and persistence. Here, we show that the reduction in the levels of cellular SUMO-conjugated proteins in S. aureus strain Newman-infected RAW 264.7 cells is associated with the S. aureus secreted protein tyrosine phosphatase PtpA, which results in a reduction of ubiquitin-conjugating enzyme 9 (Ubc9) protein level, the critical enzyme of the SUMOylation modification. In addition, we demonstrate that the amino acid residue D120, which is essential for PtpA phosphatase activity, is required for this reduction. This study shows for the first time that S. aureus strain Newman impedes via PtpA the host SUMOylation response, which contributes to promoting the persistence of S. aureus within the host.