May regulate bacterial growth in response to external signals to facilitate adaptation to the host environment. In vitro, phosphorylates several substrates such as EmbR, DevR (DosR), DacB1 and Rv0681. ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Inhibited by the kinase inhibitors staurosporine and H-7. Repressed by low pH and heat shock. Up-regulated inside the host macrophages. Autophosphorylated on threonine and serine residues. Dephosphorylated by PstP. Deletion causes hypervirulence during the chronic phase of infection in BALB/c mice. Mutant displays increased resistance to acidified nitrite stress. Does not affect sensitivity to ethambutol. Belongs to the protein kinase superfamily. Ser/Thr protein kinase family.