Toxic component of a type II toxin-antitoxin (TA) system. Phosphorylates Glu-tRNA-ligase (GltX, on 'Ser-239') in vivo. Phosphorylation of GltX prevents it from being charged, leading to an increase in uncharged tRNA(Glu). This induces amino acid starvation and the stringent response via RelA/SpoT and increased ppGpp levels, which inhibits replication, transcription, translation and cell wall synthesis, reducing growth and leading to multidrug resistance and persistence. Low level expression of HipA induces dormancy and depending on the protein level, can be toxic enough to reduce cell growth or even kill cells. Low levels of wild-type HipA lead to high beta-lactam antibiotic tolerance of the survivor cells, also dependent on relA and relA/spoT. The toxic effect of HipA is neutralized by its cognate antitoxin HipB. With HipB acts as a corepressor for transcription of the hipBA promoter; binding to DNA induces a 70 degree bend (By similarity). ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Forms a HipA(2)HipB(2) heterotetramer which can interact with DNA. Autophosphorylates intermolecularly on Ser-150; phosphorylated form not seen to bind ATP and no longer has kinase activity. Deletion of the hipB-hipA operon has no effect on virulence in mouse infection; the disrupted strain is as virulent as wild-type. Belongs to the HipA Ser/Thr kinase family. Extended N-terminus.