Phosphorylation of the transcriptional coregulator aNAC by DNA-PKcs regulates osteoblastogenesis
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PROVIDER: PRJNA594371 | ENA |
REPOSITORIES: ENA
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Project description:Phosphorylation of the transcriptional coregulator alphaNAC by DNA-PKcs regulates osteoblastogenesis
| PRJNA635498 | ENA
Project description:The αNAC (alpha chain of the Nascent polypeptide-Associated Complex) transcriptional coregulator is developmentally expressed in osteoblasts and regulates osteoblast differentiation in vitro and in vivo. αNAC can activate or repress gene transcription, a function that is dynamically regulated by post-translational modification. Phosphorylation of residue Ser132 stimulates the sumoylation of αNAC on Lys127 to repress gene expression. Using in vitro kinase assays, we show that Ser132 phosphorylation is mediated by the DNA-dependent protein kinase catalytic subunit (DNA-PKcs). Pharmacological inhibition of DNA-PKcs kinase activity or gene silencing of Prkdc (encoding DNA-PKcs) in murine osteoblastic MC3T3-E1 cells and human adipose-derived mesenchymal stromal cells markedly enhanced osteogenesis and the expression of osteoblast differentiation marker genes. ChIP-seq identified Ezh2 as a target of the αNAC/DNA-PKcs signaling pathway. Mechanistically, inhibition of DNA-PKcs repressed Ezh2 expression, induced cell cycle block, and increased osteogenesis by significantly enhancing the bone morphogenetic protein 2 (BMP-2) response in osteoblasts and other mesenchymal cells. Importantly, in vivo inhibition of the kinase enhanced bone biomechanical properties, and bones from osteoblast-specific conditional Prkdc-knockout mice exhibited increased stiffness. In conclusion, DNA-PKcs is a negative regulator of osteoblast differentiation, and therefore DNA-PKcs inhibitors may have therapeutic potential for bone regeneration and metabolic bone diseases.
2019-12-10 | GSE141686 | GEO
Project description:In order to identify pathways affected by inhibition of the DNA-dependent protein kinase, catalytic subunit in osteoblasts, we performed a whole genome gene expression profiling using the Affymetrix mouse GeneChip system (MoGene-2.0 gene ST arrays). The osteoblastic cell line MC3T3-E1 was grown in osteogenic medium and treated with DMSO (vehicle) or NU7441, an inhibitor of DNA-dependent protein kinase, for 14 days. Six biological samples were used in this experiment, three replicates in the control group and three replicates in the treated group. Isolated RNA was subjected to microarray analysis.
2020-05-28 | GSE151332 | GEO
Project description:The classical non-homologous end-joining (cNHEJ) pathway is a major DNA double-strand break repair pathway in mammalian cells and is required for lymphocyte development and maturation. The DNA-dependent protein kinase (DNA-PK) is a cNHEJ factor that encompasses the Ku70-Ku80 (KU) heterodimer and the large catalytic subunit (DNA-PKcs). In mouse models, loss of DNA-PKcs (DNA-PKcs-/-) abrogates end-processing (e.g., hairpin-opening), but not end-ligation, while expression of the kinase-dead DNA-PKcs protein (DNA-PKcsKD/KD) abrogates end-ligation, suggesting a kinases-dependent structural function of DNA-PKcs during cNHEJ. Lymphocyte development is abolished in DNA-PKcs-/- and DNA-PKcsKD/KD mice due to the requirement for both hairpin-opening and end-ligation during V(D)J recombination. DNA-PKcs itself is the best-characterized substrate of DNA-PK. The S2056-cluster is the best characterized auto-phosphorylation site on human DNA-PKcs. Here we show that radiation can induce phosphorylation of murine DNA-PKcs at the corresponding S2053 and generated knockin mouse models with alanine- (DNA-PKcsPQR) or phospho-mimetic aspartate (DNA-PKcsSD) substitutions at the S2053 cluster. Despite moderate radiation sensitivity in the DNA-PKcsPQR/PQR fibroblasts and lymphocytes, both DNA-PKcsPQR/PQR and DNA-PKcsSD/SD mice retain normal kinase activity, and undergo efficient V(D)J recombination and class switch recombination, indicating that phosphorylation at the S2053-cluster of mouse DNA-PKcs (corresponding to S2056 of human DNA-PKcs), although important for radiation resistance, is dispensable for the end-ligation and hairpin-opening function of DNA-PK essential for lymphocyte development.
2019-04-17 | GSE129895 | GEO
Project description:The non-homologous end-joining (NHEJ) pathway is a major DNA double-strand break repair pathway in mammals and is essential for lymphocyte development. Ku70 and Ku80 heterodimer (KU) initiates NHEJ, thereby recruiting and activating the catalytic subunit of DNA-dependent protein kinase (DNA-PKcs). While DNA-PKcs deletion only moderately impairs end-ligation, the expression of Kinase-dead DNA-PKcs completely abrogates NHEJ. Active DNA-PK phosphorylates DNA-PKcs at two clusters – PQR around S2056 (S2053 in mouse) and ABCDE around T2609. Alanine substitution at the S2056 cluster moderately compromises end-ligation on plasmid-based assays. But mice carrying alanine substitution at all 5 serine residues within the S2056 cluster (DNA-PKcsPQR/PQR) display no defect in lymphocyte development, leaving the physiological significance of S2056 cluster phosphorylation elusive. XLF is a non-essential NHEJ factor. Xlf-/- mice have substantial peripheral lymphocytes that are completely abolished by the loss of DNA-PKcs, the related ATM kinases, other chromatin associated DNA damage response factors (e.g., 53BP1, MDC1, H2AX, MRI, etc.) or RAG2-C-terminal regions, suggesting functional redundancy. While ATM inhibition does not further compromise end-ligation, here we show that in XLF-deficient background, DNA-PKcs S2056 cluster phosphorylation is critical for normal lymphocyte development. Chromosomal V(D)J recombination from DNA-PKcsPQR/PQRXlf-/- B cells is efficient but often has large deletions that jeopardize lymphocyte development. Class switch recombination junctions from DNA-PKcsPQR/PQRXlf-/- mice are less efficient and the residual junctions display decreased fidelity and increased deletion. These findings establish a role for DNA-PKcs S2056 cluster phosphorylation in physiological chromosomal NHEJ, implying that S2056 cluster phosphorylation contributes to the synergy between XLF and DNA-PKcs in end-ligation.
2023-05-01 | GSE228850 | GEO
Project description:The DNA-dependent protein kinase (DNA-PK), which is composed of the KU heterodimer and the large catalytic subunit (DNA-PKcs), is a classical non-homologous end-joining (cNHEJ) factor. Naïve B cells undergo class switch recombination (CSR) to generate antibodies with different isotypes by joining two DNA double-strand breaks at different switching regions via the cNHEJ pathway. DNA-PK and the cNHEJ pathway play important roles in the DNA repair phase of CSR. To initiate cNHEJ, KU binds to DNA ends and recruits and activates DNA-PK. Activated DNA-PK phosphorylates DNA-PKcs at the S2056 and T2609 clusters. Loss of T2609 cluster phosphorylation increases radiation sensitivity but whether T2609 phosphorylation has a role in physiological DNA repair remains elusive. Using the DNA-PKcs5A mouse model carrying alanine substitutions at the T2609 cluster, here we show that loss of T2609 phosphorylation of DNA-PKcs does not affect the CSR efficiency. Yet, the CSR junctions recovered from DNA-PKcs5A/5A B cells reveal increased chromosomal translocations, extensive use of distal switch regions (consistent with end-resection), and preferential usage of micro-homology – all signs of the alternative end-joining pathway. Thus, these results uncover a role of DNA-PKcs T2609 phosphorylation in promoting cNHEJ repair pathway choice during CSR.
2020-07-18 | GSE154210 | GEO
Project description:The DNA-dependent protein kinase (DNA-PK), composed of the KU heterodimer and the 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. Beyond DNA, KU also binds to RNA, with unknown significance in mammals. Using mouse models, we uncovered an unexpected role for DNA-PK in ribosomal RNA (rRNA) biogenesis and hematopoiesis. Expression of kinase-dead (KD) DNA-PKcs (DNA-PKcsKD/KD) abroagates cNHEJ2. But DNA-PKcsKD/KDTp53-/- mice develop myeloid disease rather than pro-B cell lymphoma, like other cNHEJ/Tp53-deficient mice3. DNA-PKcs is its own the best substrate. Blocking DNA-PKcs phosphorylation at the T2609, but not the S2056 cluster leads to KU-dependent 18S rRNA processing defects, compromises global protein synthesis in hematopoietic cells and causes bone marrow failure in mice. KU drives assembly of DNA-PKcs on a broad array of cellular RNAs, including the U3 small nucleolar RNA (snoRNA), which is essential for 18S rRNA processing4. U3 activates purified DNA-PK and triggers T2609 phosphorylation. DNA-PK, but not other cNHEJ factors, resides in nucleoli in an rRNA-dependent manner and is co-purified with the small subunit (SSU) processome. Together our data show that DNA-PK has RNA-dependent, but cNHEJ-independent, functions during ribosome biogenesis that require DNA-PKcs’ kinase activity and T2609 cluster’s phosphorylation.
2020-01-05 | GSE109026 | GEO
Project description:Long non-coding RNAs (lncRNAs) play important roles in cancer development and progression; however, their contributions to gastric cancer metastasis remain largely unknown. By lncRNA microarray screening, our study showed that 10 lncRNAs are dysregulated in gastric cancer tissues with or without lymph node metastasis, of which lnc-LEMGC ranks as one of the most significantly downregulated lncRNAs. Lnc-LEMGC inhibited cell migration and invasion both in vitro and in vivo, by combining with protein DNA-PKcs. Importantly, nucleotides 1,300–1,800 of lnc-LEMGC prevented DNA-PKcs phosphorylation of serine 2056 and partially abrogated the effects of downstream effectors, transforming growth factor alpha, EGFR, Src kinase, paxillin, and focal adhesion kinase, in the epidermal growth factor receptor (EGFR) pathway. The results of this study extend our knowledge of lncRNA’s molecular mechanisms, in which lnc-LEMGC functions by directly suppressing the phosphorylation of its combined protein DNA-PKcs and inactivating the DNA-PKcs downstream EGFR signaling.
2021-07-21 | GSE180443 | GEO
Project description:Two DNA repair pathways, non-homologous end joining (NHEJ) and alternative end joining (A-EJ), are involved in V(D)J recombination and chromosome translocation. Previous studies reported distinct repair mechanisms for chromosome translocation, with NHEJ predominantly involved in human and A-EJ in mice. NHEJ depends on DNA-PKcs, a critical partner in synapsis formation and downstream component activation. While DNA-PKcs inhibition promotes chromosome translocations harboring microhomologies in mice, its synonymous effect in human is not known. We find partial DNA-PKcs inhibition in human cell lines leads to increased genome-wide translocations composed mostly of direct joints, indicating the continued involvement of dampened NHEJ in these processes. In contrast, complete DNA-PKcs inhibition and genetic inhibition DNA-PKcs kinase domain substantially increased microhomology-mediated end joining (MMEJ), thus bridging the two different translocation mechanisms between human and mice. Similar to a previous study on Ku70 deletion, DNA-PKcs deletion in G1/G0-phase mouse pro-B cell lines, impair the recombination of RAG1/2-mediated DNA double-strand breaks (DSBs). This DNA-PKcs-deficient repair mechanism exhibited reduced V(D)J recombination efficiency, increased end resection, decreased polymerase-mediated insertions, loss of recombination fidelity and generated relatively higher rates of chromosome translocation as a consequence of dysregulated coding and signal end joining. Our study underscores DNA-PKcs in suppressing illegitimate chromosome rearrangement in both species.
2023-12-30 | GSE249453 | GEO
Project description:Integrative structure modelling was applied to understand how auto-phosphorylation of the ABCDE cluster in DNA-PKcs can occur. We used crosslinking restraints to assign sequence to structurally unassigned helices in DNA-PKcs s in the largely disordered region containing the ABCDE cluster. Our final model positions the ABCDE cluster at the end of the second helices, suggesting that phosphorylation occurs through trans-auto-phosphorylation, or through a large conformational change in the disordered region for cis-auto-phosphorylation.
2019-12-10 | PXD016639 | Pride