Plays an important role in slowing down the growth of mycobacteria within the infected host. ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] More abundant in the cytosol than in the cell membrane. Expression decreases during infection of human macrophages. Autophosphorylated at serine and threonine residues. Mutants show increased growth within macrophages and a hypervirulence phenotype in severe combined immunodeficiency mice. Belongs to the protein kinase superfamily. Ser/Thr protein kinase family.