2. Academic Validation
  3. DNA-PKcs has KU-dependent function in rRNA processing and haematopoiesis

DNA-PKcs has KU-dependent function in rRNA processing and haematopoiesis

  • Nature. 2020 Mar;579(7798):291-296. doi: 10.1038/s41586-020-2041-2.
Zhengping Shao # 1 2,  Ryan A Flynn # 3,  Jennifer L Crowe # 1 4,  Yimeng Zhu # 1 2,  Jialiang Liang 5,  Wenxia Jiang 1 2,  Fardin Aryan 5,  Patrick Aoude 5,  Carolyn R Bertozzi 3 6,  Verna M Estes 1 2,  Brian J Lee 1 2,  Govind Bhagat 2 7 8 9,  Shan Zha 10 11 12 13 14,  Eliezer Calo 15 16
Affiliations

Affiliations

  • 1 Institute for Cancer Genetics, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, USA.
  • 2 Herbert Irving Comprehensive Cancer Center, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, USA.
  • 3 Department of Chemistry, Stanford University, Stanford, CA, USA.
  • 4 Graduate Program of Pathobiology and Molecular Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, USA.
  • 5 Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA.
  • 6 Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA.
  • 7 Department of Pediatrics, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, USA.
  • 8 Department of Pathology and Cell Biology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, USA.
  • 9 Department of Immunology and Microbiology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, USA.
  • 10 Institute for Cancer Genetics, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, USA. [email protected].
  • 11 Herbert Irving Comprehensive Cancer Center, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, USA. [email protected].
  • 12 Department of Pediatrics, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, USA. [email protected].
  • 13 Department of Pathology and Cell Biology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, USA. [email protected].
  • 14 Department of Immunology and Microbiology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, USA. [email protected].
  • 15 Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA. [email protected].
  • 16 Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, USA. [email protected].
  • # Contributed equally.
PMID: 32103174 DOI: 10.1038/s41586-020-2041-2
Abstract

The DNA-dependent protein kinase (DNA-PK), which comprises the KU heterodimer and a catalytic subunit (DNA-PKcs), is a classical non-homologous end-joining (cNHEJ) factor1. KU binds to DNA ends, initiates cNHEJ, and recruits and activates DNA-PKcs. KU also binds to RNA, but the relevance of this interaction in mammals is unclear. Here we use mouse models to show that DNA-PK has an unexpected role in the biogenesis of ribosomal RNA (rRNA) and in haematopoiesis. The expression of kinase-dead DNA-PKcs abrogates cNHEJ2. However, most mice that both expressed kinase-dead DNA-PKcs and lacked the tumour suppressor TP53 developed myeloid disease, whereas all other previously characterized mice deficient in both cNHEJ and TP53 expression succumbed to pro-B cell lymphoma3. DNA-PK autophosphorylates DNA-PKcs, which is its best characterized substrate. Blocking the phosphorylation of DNA-PKcs at the T2609 cluster, but not the S2056 cluster, led to KU-dependent defects in 18S rRNA processing, compromised global protein synthesis in haematopoietic cells and caused bone marrow failure in mice. KU drives the assembly of DNA-PKcs on a wide range of cellular RNAs, including the U3 small nucleolar RNA, which is essential for processing of 18S rRNA4. U3 activates purified DNA-PK and triggers phosphorylation of DNA-PKcs at T2609. DNA-PK, but not other cNHEJ factors, resides in nucleoli in an rRNA-dependent manner and is co-purified with the small subunit processome. Together our data show that DNA-PK has RNA-dependent, cNHEJ-independent functions during ribosome biogenesis that require the kinase activity of DNA-PKcs and its phosphorylation at the T2609 cluster.

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