DNA-PKcs kinase activity stabilizes the transcription factor Egr1 in activated immune cells

Abstract

DNA-dependent protein kinase catalytic subunit (DNA-PKcs) is known primarily for its function in DNA double-stranded break repair and nonhomologous end joining (NHEJ). However, DNA-PKcs also has a critical yet undefined role in immunity impacting both myeloid and lymphoid cell lineages spurring interest in targeting DNA-PKcs for therapeutic strategies in immune-related diseases. To gain insight into the function of DNA-PKcs within immune cells, we performed a quantitative phosphoproteomic screen in T cells to identify phosphorylation targets of DNA-PKcs. Our results indicate that DNA-PKcs phosphorylates the transcription factor Egr1 (early growth response protein 1) at serine 301. Expression of Egr1 is induced early upon T cell activation and dictates T cell response of and and of DNA-PKcs a DNA-PKcs of of serine to protein and transcription of in T Our identify DNA-PKcs a critical T cell activation and T cell and a in Egr1 DNA-dependent protein kinase catalytic subunit (DNA-PKcs) is known primarily for its function in DNA double-stranded break repair and nonhomologous end joining (NHEJ). However, DNA-PKcs also has a critical yet undefined role in immunity impacting both myeloid and lymphoid cell lineages spurring interest in targeting DNA-PKcs for therapeutic strategies in immune-related diseases. To gain insight into the function of DNA-PKcs within immune cells, we performed a quantitative phosphoproteomic screen in T cells to identify phosphorylation targets of DNA-PKcs. Our results indicate that DNA-PKcs phosphorylates the transcription factor Egr1 (early growth response protein 1) at serine 301. Expression of Egr1 is induced early upon T cell activation and dictates T cell response of and and of DNA-PKcs a DNA-PKcs of of serine to protein and transcription of in T Our identify DNA-PKcs a critical T cell activation and T cell and a in Egr1 function for DNA-dependent protein kinase catalytic subunit DNA-PKcs is in the and repair of DNA nonhomologous end joining (NHEJ). However, kinase of function in DNA-PKcs a in and and T cell in a repair DNA for repair of DNA of the catalytic subunit of the in and DNA-PKcs in primarily to the function of DNA-PKcs in is for and in immune cells in is in and DNA-PKcs in T DNA-dependent protein kinase in and and function a function for DNA-PKcs in the immune that is yet to cells a of the immune response T cell and a of to of T cells in and that T cell is critical for the of to T T cell activation that T cell and end is the activation of transcription that of and the and T cell of the transcription factor in T cells T cell a cell of transcription and T cells is that DNA-PKcs T cell immune cells, of transcription factor T cells, DNA-PKcs of both and a of and DNA-dependent protein kinase in and and function cells to DNA-dependent protein Our that DNA-PKcs also of the subunit of in T cells, and of DNA-PKcs of DNA-PKcs that DNA DNA-PKcs activation of the immune response the transcription factor and its into the to is a DNA 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protein kinase catalytic subunit DNA-PKcs is in the and repair of DNA nonhomologous end joining (NHEJ). 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DNA for indicate that DNA-PKcs a role in the of to the of DNA-PKcs the of to the and of DNA-PKcs in T we that DNA-PKcs also of the early response Egr1 (early growth response a transcription factor critical for is in T of early growth response is for the of cells to and and growth response the Egr1 within of to transcription of for immune cell function activation and early response in and of early response factor and of kinase of transcription and its a transcription factor in the the of targeting to T cell immunity and for T cells response the of Egr1 to a phosphorylation of DNA-PKcs. of DNA-PKcs of serine of Egr1 in of Egr1 protein to of of early Egr1 that DNA-PKcs a critical and transcription of T cell is DNA-PKcs of T the of in DNA-PKcs is we to identify DNA-PKcs phosphorylation targets in T cell To we performed a quantitative screen for T cells and and and a kinase of DNA-PKcs of a DNA-dependent protein kinase of DNA-PKcs of break of quantitative for a quantitative and of 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double-stranded DNA of is that is also a critical of the immune is a to DNA-PKcs. and to in both the and of and cells to T the kinase in cells the immune response and in in T cells is critical for immune of in in and a yet undefined of immune of to DNA-PKcs to T cell activation phosphoproteomic screen that the transcription factor Egr1 is a of DNA-PKcs. of Egr1 at DNA-PKcs is for protein and of the within Egr1 has to critical for of Egr1 in that kinase phosphorylates Egr1 within Egr1 to DNA and transcription kinase and a of its DNA and transcription in Our the of and the of Egr1 within of activation and in T cell to activation and early response in in the response a role for DNA-PKcs in and of Egr1 that has a immune response and a therapeutic for a of immune-related that DNA-PKcs is a critical of the T cell response to DNA-PKcs of DNA-PKcs T cells a of in response to in in a therapeutic for the of we in that the in DNA-PKcs to a in protein of the subunit the of Egr1 also in that Egr1 a critical of that phosphorylation of Egr1 DNA-PKcs its the in the of of Egr1 the in and in has for DNA-PKcs DNA-PKcs in phosphorylation at of the break repair kinase and that DNA-PKcs transcription of of the DNA-PKcs in T in the that phosphorylation of Egr1 its and the kinase and a of its DNA and transcription in is that phosphorylation DNA-PKcs at that a DNA-PKcs has also to of for in to transcription at that DNA-PKcs of transcription for transcription and repair at DNA indicate that DNA-PKcs the a to the T cell response to of transcription in T cell that DNA-PKcs activation T cell and DNA-PKcs to and DNA-PKcs phosphorylation targets a of immune that T cells to and critical targets for for immune-related diseases. DNA-PKcs is a of double-stranded DNA of is that is also a critical of the immune is a to DNA-PKcs. and to in both the and of and cells to T the kinase in cells the immune response and in in T cells is critical for immune of in in and a yet undefined of immune of to DNA-PKcs to T cell activation phosphoproteomic screen that the transcription factor Egr1 is a of DNA-PKcs. of Egr1 at DNA-PKcs is for protein and of the within Egr1 has to critical for of Egr1 in that kinase phosphorylates Egr1 within Egr1 to DNA and transcription kinase and a of its DNA and transcription in Our the of and the of Egr1 within of activation and in T cell to activation and early response in in the response a role for DNA-PKcs in and of Egr1 that has a immune response and a therapeutic for a of immune-related that DNA-PKcs is a critical of the T cell response to DNA-PKcs of DNA-PKcs T cells a of in response to in in a therapeutic for the of we in that the in DNA-PKcs to a in protein of the subunit the of Egr1 also in that Egr1 a critical of that phosphorylation of Egr1 DNA-PKcs its the in the of of Egr1 the in and in has for DNA-PKcs DNA-PKcs in phosphorylation at of the break repair kinase and that DNA-PKcs transcription of of the DNA-PKcs in T in the that phosphorylation of Egr1 its and the kinase and a of its DNA and transcription in is that phosphorylation DNA-PKcs at that a DNA-PKcs has also to of for in to transcription at that DNA-PKcs of transcription for transcription and repair at DNA indicate that DNA-PKcs the a to the T cell response to of transcription in T cell that DNA-PKcs activation T cell and DNA-PKcs to and DNA-PKcs phosphorylation targets a of immune that T cells to and critical targets for for immune-related diseases. cells and and in and cells in and cells at a of for to and and and for in and in a the and protein the in into for to a a at for and and a and to the the to of cells and for and at and and to and a and and the and into a a to and into a to the in at a of a of activation of the in and to for activation of of the in at a of a of to for and performed and the a of a of a of protein and phosphorylation and of the for of the catalytic subunit of the in and the for and protein the to the the the the results to the to for kinase and to Egr1 of to the in a of in kinase Egr1 and of in a of at performed the of kinase for to the in kinase the of Egr1 in performed in the of and a to the in at a of a of the in and a of a of and a of transcription the performed in and a the to of the to for of cells to the of cells the the and the both cells for in cells at in for to and of cell to the of a for for at and the and performed in the of the performed the of to performed of and the performed in cells and and in and cells in and cells at a of for to and and and cells and and in and cells in and cells at a of for to and and and for in and in a the and protein the in into for to a a at for and and a for in and in a the and protein the in into for to a a at for and and a and to the the and to the the to of cells and for and at and and to and a and and the and into a a to and into a to the in at a of a of activation of the in and to for activation of of the in at a of a of to for and performed and the a of a of a of protein and phosphorylation and of the for of the catalytic subunit of the in and the for and protein the to the the the the results to the to for to of cells and for and at and and to and a and and the and into a a to and into a to the in at a of a of activation of the in and to for activation of of the in at a of a of to for and performed and the a of a of a of protein and phosphorylation and of the for of the catalytic subunit of the in and the for and protein the to the the the the results to the to for kinase and to Egr1 of to the in a of in kinase Egr1 and of in a of at performed the and to Egr1 of to the in a of in kinase Egr1 and of in a of at performed the of kinase for to the in kinase the of Egr1 in performed in the of and a to the in at a of a of the in and a of a of and a of for to the in kinase the of Egr1 in performed in the of and a to the in at a of a of the in and a of a of and a of transcription the performed in and a the to of the to for transcription the performed in and a the to of the to for of cells to the of cells the the and the both cells for in of cells to the of cells the the and the both cells for in cells at in for to and of cell to the of a for for at and the and performed in the of the performed the of to performed cells at in for to and of cell to the of a for for at and the and performed in the of the performed the of to performed of and the performed in of and the performed in to the the the for and upon is within the to the the the for and upon is within the that of interest the of in the the of of the also to the DNA at the for and for the for and the the for of the and and and and and and and and is the of the and the of the the to

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