@article{open3399,
          volume = {19},
          number = {12},
           month = {December},
          author = {Prabhat Ranjan Singh and Harsh Goar and Partha Paul and Khushboo Mehta and Bhanwar Bamniya and Anil Kumar Vijjamarri and Roohi Bansal and Hina Khan and Subramanian Karthikeyan and Dibyendu Sarkar},
            note = {Copyright of this article belongs to Pub Med Central},
           title = {Dual functioning by the PhoR sensor is a key determinant to Mycobacterium tuberculosis virulence},
       publisher = {Pub Med Central},
            year = {2023},
         journal = {PLoS Genet.},
           pages = {e1011070},
             url = {http://crdd.osdd.net/open/3399/},
        abstract = {PhoP-PhoR, one of the 12 two-component systems (TCSs) that empower M. tuberculosis to sense and adapt to diverse environmental conditions, remains essential for virulence, and therefore, represents a major target to develop novel anti-TB therapies. Although both PhoP and PhoR have been structurally characterized, the signal(s) that this TCS responds to remains unknown. Here, we show that PhoR is a sensor of acidic pH/high salt conditions, which subsequently activate PhoP via phosphorylation. In keeping with this, transcriptomic data uncover that acidic pH- inducible expression of PhoP regulon is significantly inhibited in a PhoR-deleted M. tuberculosis. Strikingly, a set of PhoP regulon genes displayed a low pH-dependent activation even in the absence of PhoR, suggesting the presence of non-canonical mechanism(s) of PhoP activation. Using genome-wide interaction-based screening coupled with phosphorylation assays, we identify a non-canonical mechanism of PhoP phosphorylation by the sensor kinase PrrB. To investigate how level of P{\texttt{\char126}}PhoP is regulated, we discovered that in addition to its kinase activity PhoR functions as a phosphatase of P{\texttt{\char126}}PhoP. Our subsequent results identify the motif/residues responsible for kinase/phosphatase dual functioning of PhoR. Collectively, these results uncover that contrasting kinase and phosphatase functions of PhoR determine the homeostatic mechanism of regulation of intra-mycobacterial P{\texttt{\char126}}PhoP which controls the final output of the PhoP regulon. Together, these results connect PhoR to pH-dependent activation of PhoP with downstream functioning of the regulator. Thus, PhoR plays a central role in mycobacterial adaptation to low pH conditions within the host macrophage phagosome, and a PhoR-deleted M. tuberculosis remains significantly attenuated in macrophages and animal models.}
}