Protein: HIPA_ECOLI
Sequence: MPKLVTWMNNQRVGELTKLANGAHTFKYAPEWLASRYARPLSLSLPLQRGNITSDAVFNFFDNLLPDSPIVRDRIVKRYHAKSRQPFDLLSEIGRDSVGAVTLIPEDETVTHPIMAWEKLTEARLEEVLTAYKADIPLGMIREENDFRISVAGAQEKTALLRIGNDWCIPKGITPTTHIIKLPIGEIRQPNATLDLSQSVDNEYYCLLLAKELGLNVPDAEIIKAGNVRALAVERFDRRWNAERTVLLRLPQEDMCQTFGLPSSVKYESDGGPGIARIMAFLMGSSEALKDRYDFMKFQVFQWLIGATDGHAKNFSVFIQAGGSYRLTPFYDIISAFPVLGGTGIHISDLKLAMGLNASKGKKTAIDKIYPRHFLATAKVLRFPEVQMHEILSDFARMIPAALDNVKTSLPTDFPENVVTAVESNVLRLHGRLSREYGSK
What is the function of this protein?
Toxic component of a type II toxin-antitoxin (TA) system, first identified by mutations that increase production of persister cells, a fraction of cells that are phenotypic variants not killed by antibiotics, which lead to multidrug tolerance (PubMed:6348026, PubMed:8021189, PubMed:16707675, PubMed:26222023).  Persistence may be ultimately due to global remodeling of the persister cell's ribosomes (PubMed:25425348).  Phosphorylates Glu-tRNA-ligase (AC P04805, gltX, on 'Ser-239') in vivo (PubMed:24095282, PubMed:24343429).  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 (p)ppGpp levels, which inhibits replication, transcription, translation and cell wall synthesis, reducing growth and leading to persistence and multidrug resistance (PubMed:24095282, PubMed:24343429).  Once the level of HipA exceeds a threshold cells become dormant, and the length of dormancy is determined by how much HipA levels exceed the threshold (PubMed:20616060).  The hipA7 mutation (a double G22S D291A mutation) leads to increased generation of persister cells (cells that survive antibiotic treatment) probably by entering into a dormant state, as well as cold-sensitivity (PubMed:14622409, PubMed:16707675).  Wild-type cells produce persisters at a frequency of 10(-6) to 10(-5) whereas hipA7 cells produce about 100-fold more persisters (PubMed:14622409, PubMed:16707675, PubMed:25425348).  hipA7 decreases the affinity for antitoxin HipB, leading to increased HipA levels and persistence (PubMed:20616060); depending on the protein level, can be toxic enough to reduce cell growth or even kill cells.  Generation of persister cells requires (p)ppGpp as cells lacking relA or relA/spoT generate fewer or no persister cells respectively compared to hipA7 (PubMed:14622409).  The toxic effect of HipA is neutralized by its cognate antitoxin HipB (PubMed:20616060).  Also neutralized by overexpression of gltX (PubMed:24343429, PubMed:28430938).  With HipB acts as a corepressor for transcription of the hipBA promoter (PubMed:8021189); binding of HipA-HipB to DNA induces a 70 degree bend (PubMed:19150849, PubMed:26222023).  This brings together and dimerizes 2 HipA molecules, which distorts the promoter region, preventing sigma-factor binding; additionally HipA and HipB would physically prevent RNA core polymerase from contacting the -35 promoter box (PubMed:26222023).  May play a role in biofilm formation (PubMed:23329678).
What are the official names of this protein?
Serine/threonine-protein kinase toxin HipA, Ser/Thr-protein kinase HipA, Toxin HipA.
What is the protein family that this protein belongs to?
Belongs to the HipA Ser/Thr kinase family.