Protein kinase that regulates many aspects of mycobacterial physiology. Is a key component of a signal transduction pathway that regulates cell growth, cell shape and cell division via phosphorylation of target proteins (By similarity). Probably phosphorylates RseA (PubMed:20025669). ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] By K-252a. Homodimer. The PASTA domains interact with peptidoglycans and are required for PknB localization. Autophosphorylated. Dephosphorylated by PstP (By similarity). When depleted (with anti-sense RNA) no vancomycin-induced degradation of RseA is seen. Belongs to the protein kinase superfamily. Ser/Thr protein kinase family.