7z88
From Proteopedia
DNA-PK in the intermediate state
Structural highlights
DiseasePRKDC_HUMAN Severe combined immunodeficiency due to DNA-PKcs deficiency. The disease is caused by mutations affecting the gene represented in this entry. FunctionPRKDC_HUMAN Serine/threonine-protein kinase that acts as a molecular sensor for DNA damage. Involved in DNA non-homologous end joining (NHEJ) required for double-strand break (DSB) repair and V(D)J recombination. Must be bound to DNA to express its catalytic properties. Promotes processing of hairpin DNA structures in V(D)J recombination by activation of the hairpin endonuclease artemis (DCLRE1C). The assembly of the DNA-PK complex at DNA ends is also required for the NHEJ ligation step. Required to protect and align broken ends of DNA. May also act as a scaffold protein to aid the localization of DNA repair proteins to the site of damage. Found at the ends of chromosomes, suggesting a further role in the maintenance of telomeric stability and the prevention of chromosomal end fusion. Also involved in modulation of transcription. Recognizes the substrate consensus sequence [ST]-Q. Phosphorylates 'Ser-139' of histone variant H2AX/H2AFX, thereby regulating DNA damage response mechanism. Phosphorylates DCLRE1C, c-Abl/ABL1, histone H1, HSPCA, c-jun/JUN, p53/TP53, PARP1, POU2F1, DHX9, SRF, XRCC1, XRCC1, XRCC4, XRCC5, XRCC6, WRN, MYC and RFA2. Can phosphorylate C1D not only in the presence of linear DNA but also in the presence of supercoiled DNA. Ability to phosphorylate p53/TP53 in the presence of supercoiled DNA is dependent on C1D. Contributes to the determination of the circadian period length by antagonizing phosphorylation of CRY1 'Ser-588' and increasing CRY1 protein stability, most likely through an indirect machanism. Interacts with CRY1 and CRY2; negatively regulates CRY1 phosphorylation.[1] [2] [3] [4] Publication Abstract from PubMedDNA-dependent protein kinase (DNA-PK), a multicomponent complex including the DNA-PK catalytic subunit and Ku70/80 heterodimer together with DNA, is central to human DNA damage response and repair. Using a DNA-PK-selective inhibitor (M3814), we identified from one dataset two cryo-EM structures of the human DNA-PK complex in different states, the intermediate state and the active state. Here we show that activation of the kinase is regulated through conformational changes caused by the binding ligand and the string region (residues 802-846) of the DNA-PK catalytic subunit, particularly the helix-hairpin-helix motif (residues 816-836) that interacts with DNA. These observations demonstrate the regulatory role of the ligand and explain why DNA-PK is DNA dependent. Cooperation and coordination among binding partners, disordered flexible regions and mechanically flexible HEAT repeats modulate the activation of the kinase. Together with previous findings, these results provide a better molecular understanding of DNA-PK catalysis. Human DNA-dependent protein kinase activation mechanism.,Liang S, Blundell TL Nat Struct Mol Biol. 2023 Feb;30(2):140-147. doi: 10.1038/s41594-022-00881-w. , Epub 2023 Jan 5. PMID:36604499[5] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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