Hairpin Opening and Overhang Processing by an Artemis/DNA-Dependent Protein Kinase Complex in Nonhomologous End Joining and V(D)J Recombination

• Published in: Cell 2002-03, Vol.108 (6), p.781-794
• Main Authors: Ma, Yunmei, Pannicke, Ulrich, Schwarz, Klaus, Lieber, Michael R.
• Format: Article
• Language: English
• Subjects: Adenosine Triphosphate - metabolism; Animals; beta-Lactamases - genetics; beta-Lactamases - metabolism; DNA, Single-Stranded - chemistry; DNA, Single-Stranded - metabolism; DNA-Activated Protein Kinase; DNA-Binding Proteins - metabolism; Endonucleases - genetics; Endonucleases - metabolism; Enzyme Activation; HMGB1 Protein - metabolism; Homeodomain Proteins - metabolism; Humans; Nuclear Proteins; Phosphorylation; Protein-Serine-Threonine Kinases - genetics; Protein-Serine-Threonine Kinases - metabolism; Recombination, Genetic - physiology
• ISSN: 0092-8674; 1097-4172
• DOI: 10.1016/S0092-8674(02)00671-2

Mutations in the Artemis protein in humans result in hypersensitivity to DNA double-strand break-inducing agents and absence of B and T lymphocytes (radiosensitive severe combined immune deficiency [RS-SCID]). Here, we report that Artemis forms a complex with the 469 kDa DNA-dependent protein kinase (DNA-PK cs) in the absence of DNA. The purified Artemis protein alone possesses single-strand-specific 5′ to 3′ exonuclease activity. Upon complex formation, DNA-PK cs phosphorylates Artemis, and Artemis acquires endonucleolytic activity on 5′ and 3′ overhangs, as well as hairpins. Finally, the Artemis:DNA-PK cs complex can open hairpins generated by the RAG complex. Thus, DNA-PK cs regulates Artemis by both phosphorylation and complex formation to permit enzymatic activities that are critical for the hairpin-opening step of V(D)J recombination and for the 5′ and 3′ overhang processing in nonhomologous DNA end joining.