Protein kinase that regulates many aspects of mycobacterial physiology, and is critical for growth in vitro and survival of the pathogen in the host (PubMed:25713147). Is a key component of a signal transduction pathway that regulates cell growth, cell shape and cell division via phosphorylation of target proteins such as FtsZ, Wag31, GlmU, PstP, EmbR and Rv1422 (PubMed:15985609, PubMed:16817899, PubMed:19121323, PubMed:21190553, PubMed:21423706). Also catalyzes the phosphorylation of the proteasome alpha-subunit (PrcA) and unprocessed proteasome beta-subunit (pre-PrcB), which results in the inhibition of processing of pre-PrcB and assembly of the proteasome complex, and thereby enhances the mycobacterial resistance to H(2)O(2); PknA thus plays an important role in the oxidative stress response by impeding the formation of holo-proteasome in M.tuberculosis under H(2)O(2) stress (PubMed:25224505). Shows a strong preference for Thr versus Ser as the phosphoacceptor. ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Is activated by autophosphorylation of activation loop threonine residues, which results in conformational change and allows substrate binding. It seems that following ATP binding, phosphate is first transferred to Thr-180 via a cis mechanism to activate the kinase activity; phosphorylation of Thr-180 triggers PknA to phosphorylate Thr-172/Thr-174 via a trans mechanism. Phosphorylation of all of the activation loop threonines is necessary for efficient catalytic activity. The majority of the cells displays PknA expression at the membrane perimeter along the length of the cell, whereas a minor population shows PknA to localize at either or both poles (uni- and bipolar; 16 and 14%, respectively) and occasionally to both the poles and the midcell (12%). Expressed predominantly in exponential phase. The extracellular domain is dispensable for cell growth and survival in vitro (PubMed:25713147). The catalytic activity of PknA is confined within the N-terminal 283 amino acids (PubMed:25665034). Autophosphorylated (PubMed:16739134) (PubMed:25665034) (PubMed:25586004). Phosphorylation of Thr-180 in the activation loop is critical for the functionality of PknA (PubMed:25665034). Autophosphorylation level increases in the presence of H(2)O(2) suggesting that PknA is activated by H(2)O(2) (PubMed:25224505). Phosphorylation of the activation loop at Thr-172 of PknA is critical for bacterial growth; PknA autophosphorylates its activation loop independent of PknB (PubMed:25713147). Dephosphorylated by PstP (PubMed:16817899). PknA depletion in M.tuberculosis results in cell death and aberrant cell morphology, and leads to complete clearance of the pathogen from the host tissues using the murine infection model. Overexpression causes major growth and morphological changes that indicate defects in cell wall synthesis and possibly in cell division. Belongs to the protein kinase superfamily. Ser/Thr protein kinase family. The article by Sureka et al was retracted by the editors after publication. Concerns were raised regarding the results presented in multiple figure panels. The raw data or replacement panels that were available did not satisfactorily address all the issues, thus questioning the integrity of the data.