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• W2038771520 abstract "•Type I IFNs induce phosphorylation of ULK1 at serine 757•ULK activity mediates transcriptional activation of ISGs and activation of p38 MAPK•IFN-dependent activation of ULK1/2 is essential for generation of antiviral responses•ULK1 is required for IFN-induced antineoplastic effects in MPN progenitors We provide evidence that the Unc-51-like kinase 1 (ULK1) is activated during engagement of the type I interferon (IFN) receptor (IFNR). Our studies demonstrate that the function of ULK1 is required for gene transcription mediated via IFN-stimulated response elements (ISRE) and IFNγ activation site (GAS) elements and controls expression of key IFN-stimulated genes (ISGs). We identify ULK1 as an upstream regulator of p38α mitogen-activated protein kinase (MAPK) and establish that the regulatory effects of ULK1 on ISG expression are mediated possibly by engagement of the p38 MAPK pathway. Importantly, we demonstrate that ULK1 is essential for antiproliferative responses and type I IFN-induced antineoplastic effects against malignant erythroid precursors from patients with myeloproliferative neoplasms. Together, these data reveal a role for ULK1 as a key mediator of type I IFNR-generated signals that control gene transcription and induction of antineoplastic responses. We provide evidence that the Unc-51-like kinase 1 (ULK1) is activated during engagement of the type I interferon (IFN) receptor (IFNR). Our studies demonstrate that the function of ULK1 is required for gene transcription mediated via IFN-stimulated response elements (ISRE) and IFNγ activation site (GAS) elements and controls expression of key IFN-stimulated genes (ISGs). We identify ULK1 as an upstream regulator of p38α mitogen-activated protein kinase (MAPK) and establish that the regulatory effects of ULK1 on ISG expression are mediated possibly by engagement of the p38 MAPK pathway. Importantly, we demonstrate that ULK1 is essential for antiproliferative responses and type I IFN-induced antineoplastic effects against malignant erythroid precursors from patients with myeloproliferative neoplasms. Together, these data reveal a role for ULK1 as a key mediator of type I IFNR-generated signals that control gene transcription and induction of antineoplastic responses. Type I interferons (IFNs) are cytokines with important antitumor, antiviral, and immunomodulatory properties (González-Navajas et al., 2012González-Navajas J.M. Lee J. David M. Raz E. Immunomodulatory functions of type I interferons.Nat. Rev. Immunol. 2012; 12: 125-135PubMed Google Scholar, Bekisz et al., 2013Bekisz J. Sato Y. Johnson C. Husain S.R. Puri R.K. Zoon K.C. Immunomodulatory effects of interferons in malignancies.J. Interferon Cytokine Res. 2013; 33: 154-161Crossref PubMed Scopus (36) Google Scholar, Platanias, 2005Platanias L.C. Mechanisms of type-I- and type-II-interferon-mediated signalling.Nat. Rev. Immunol. 2005; 5: 375-386Crossref PubMed Scopus (2210) Google Scholar). These cytokines have clinical activity against viral infections and several human malignancies (Hervas-Stubbs et al., 2011Hervas-Stubbs S. Perez-Gracia J.L. Rouzaut A. Sanmamed M.F. Le Bon A. Melero I. Direct effects of type I interferons on cells of the immune system.Clin. Cancer Res. 2011; 17: 2619-2627Crossref PubMed Scopus (331) Google Scholar, Bekisz et al., 2013Bekisz J. Sato Y. Johnson C. Husain S.R. Puri R.K. Zoon K.C. Immunomodulatory effects of interferons in malignancies.J. Interferon Cytokine Res. 2013; 33: 154-161Crossref PubMed Scopus (36) Google Scholar, Kotredes and Gamero, 2013Kotredes K.P. Gamero A.M. Interferons as inducers of apoptosis in malignant cells.J. Interferon Cytokine Res. 2013; 33: 162-170Crossref PubMed Scopus (82) Google Scholar, Platanias, 2013Platanias L.C. Interferons and their antitumor properties.J. Interferon Cytokine Res. 2013; 33: 143-144Crossref PubMed Scopus (20) Google Scholar, Stein and Tiu, 2013Stein B.L. Tiu R.V. Biological rationale and clinical use of interferon in the classical BCR-ABL-negative myeloproliferative neoplasms.J. Interferon Cytokine Res. 2013; 33: 145-153Crossref PubMed Scopus (33) Google Scholar). Despite continuing efforts to define the precise mechanisms by which IFNs generate antineoplastic responses, the sequence of events and the specific coordination of different IFN-activated signaling cascades required for such responses remain incompletely defined (Platanias, 2013Platanias L.C. Interferons and their antitumor properties.J. Interferon Cytokine Res. 2013; 33: 143-144Crossref PubMed Scopus (20) Google Scholar). All type I IFNs bind to type I IFN receptor (IFNR), the engagement of which activates JAK-STAT (Janus-activated kinase-signal transducer and activator of transcription) signaling pathways (Platanias, 2005Platanias L.C. Mechanisms of type-I- and type-II-interferon-mediated signalling.Nat. Rev. Immunol. 2005; 5: 375-386Crossref PubMed Scopus (2210) Google Scholar, Stark and Darnell, 2012Stark G.R. Darnell Jr., J.E. The JAK-STAT pathway at twenty.Immunity. 2012; 36: 503-514Abstract Full Text Full Text PDF PubMed Scopus (879) Google Scholar, Ivashkiv and Donlin, 2014Ivashkiv L.B. Donlin L.T. Regulation of type I interferon responses.Nat. Rev. Immunol. 2014; 14: 36-49Crossref PubMed Scopus (1623) Google Scholar). Beyond these pathways, activation of several other IFN-signaling cascades occurs during engagement of IFN receptors, including the p38 mitogen-activated protein kinase (MAPK) pathway (Uddin et al., 1999Uddin S. Majchrzak B. Woodson J. Arunkumar P. Alsayed Y. Pine R. Young P.R. Fish E.N. Platanias L.C. Activation of the p38 mitogen-activated protein kinase by type I interferons.J. Biol. Chem. 1999; 274: 30127-30131Crossref PubMed Scopus (207) Google Scholar, Li et al., 2004Li Y. Sassano A. Majchrzak B. Deb D.K. Levy D.E. Gaestel M. Nebreda A.R. Fish E.N. Platanias L.C. Role of p38alpha Map kinase in Type I interferon signaling.J. Biol. Chem. 2004; 279: 970-979Crossref PubMed Scopus (97) Google Scholar), the phosphatidylinositol 3-kinase (PI3K)-AKT pathway (Kaur et al., 2008aKaur S. Sassano A. Joseph A.M. Majchrzak-Kita B. Eklund E.A. Verma A. Brachmann S.M. Fish E.N. Platanias L.C. Dual regulatory roles of phosphatidylinositol 3-kinase in IFN signaling.J. Immunol. 2008; 181: 7316-7323Crossref PubMed Scopus (69) Google Scholar, Kaur et al., 2008bKaur S. Sassano A. Dolniak B. Joshi S. Majchrzak-Kita B. Baker D.P. Hay N. Fish E.N. Platanias L.C. Role of the Akt pathway in mRNA translation of interferon-stimulated genes.Proc. Natl. Acad. Sci. USA. 2008; 105: 4808-4813Crossref PubMed Scopus (163) Google Scholar), and the mammalian target of rapamycin complex 1 (mTORC1) and mTORC2 signaling cascades (Kaur et al., 2007Kaur S. Lal L. Sassano A. Majchrzak-Kita B. Srikanth M. Baker D.P. Petroulakis E. Hay N. Sonenberg N. Fish E.N. Platanias L.C. Regulatory effects of mammalian target of rapamycin-activated pathways in type I and II interferon signaling.J. Biol. Chem. 2007; 282: 1757-1768Crossref PubMed Scopus (94) Google Scholar, Kaur et al., 2012Kaur S. Sassano A. Majchrzak-Kita B. Baker D.P. Su B. Fish E.N. Platanias L.C. Regulatory effects of mTORC2 complexes in type I IFN signaling and in the generation of IFN responses.Proc. Natl. Acad. Sci. USA. 2012; 109: 7723-7728Crossref PubMed Scopus (41) Google Scholar, Kaur et al., 2014Kaur S. Kroczynska B. Sharma B. Sassano A. Arslan A.D. Majchrzak-Kita B. Stein B.L. McMahon B. Altman J.K. Su B. et al.Critical roles for Rictor/Sin1 complexes in interferon-dependent gene transcription and generation of antiproliferative responses.J. Biol. Chem. 2014; 289: 6581-6591Crossref PubMed Scopus (17) Google Scholar). The functions of these pathways are essential for optimal transcription and/or mRNA translation of various interferon-stimulated genes (ISGs) that are needed for the induction of IFN-responses (Kaur et al., 2007Kaur S. Lal L. Sassano A. Majchrzak-Kita B. Srikanth M. Baker D.P. Petroulakis E. Hay N. Sonenberg N. Fish E.N. Platanias L.C. Regulatory effects of mammalian target of rapamycin-activated pathways in type I and II interferon signaling.J. Biol. Chem. 2007; 282: 1757-1768Crossref PubMed Scopus (94) Google Scholar, Kaur et al., 2008bKaur S. Sassano A. Dolniak B. Joshi S. Majchrzak-Kita B. Baker D.P. Hay N. Fish E.N. Platanias L.C. Role of the Akt pathway in mRNA translation of interferon-stimulated genes.Proc. Natl. Acad. Sci. USA. 2008; 105: 4808-4813Crossref PubMed Scopus (163) Google Scholar, Kaur et al., 2014Kaur S. Kroczynska B. Sharma B. Sassano A. Arslan A.D. Majchrzak-Kita B. Stein B.L. McMahon B. Altman J.K. Su B. et al.Critical roles for Rictor/Sin1 complexes in interferon-dependent gene transcription and generation of antiproliferative responses.J. Biol. Chem. 2014; 289: 6581-6591Crossref PubMed Scopus (17) Google Scholar). Although the relevance and functional importance of mTORC1 signals in promoting functional IFN responses is well established (Kaur et al., 2007Kaur S. Lal L. Sassano A. Majchrzak-Kita B. Srikanth M. Baker D.P. Petroulakis E. Hay N. Sonenberg N. Fish E.N. Platanias L.C. Regulatory effects of mammalian target of rapamycin-activated pathways in type I and II interferon signaling.J. Biol. Chem. 2007; 282: 1757-1768Crossref PubMed Scopus (94) Google Scholar), the precise mechanisms and distinct roles of downstream mTORC1 effectors in the process remain to be defined. Previous work has demonstrated that activated mTORC1 prevents autophagy by phosphorylation of serine 757 (Ser757) of Unc-51-like kinase 1 (ULK1) and by disrupting the interaction between ULK1 and AMP-activated protein kinase (AMPK) (Kim et al., 2011Kim J. Kundu M. Viollet B. Guan K.L. AMPK and mTOR regulate autophagy through direct phosphorylation of Ulk1.Nat. Cell Biol. 2011; 13: 132-141Crossref PubMed Scopus (4214) Google Scholar). ULK1 and ULK2 are the closely related mammalian homologs of the serine/threonine autophagy-related (ATG) protein kinase ATG1, the first identified ATG product in yeast, and both are involved in the regulation of autophagy (Alers et al., 2012Alers S. Löffler A.S. Wesselborg S. Stork B. The incredible ULKs.Cell Commun. Signal. 2012; 10: 7Crossref PubMed Scopus (68) Google Scholar). In the present study, we examined whether ULK1 is engaged in IFN signaling and what role it plays in the induction of type I IFN-mediated responses. Our studies provide evidence implicating ULK1 in type I IFN signaling and transcriptional activation of ISGs and define a mechanism by which such ULK1-mediated activity occurs in the IFN system, possibly involving regulation/activation of p38 MAPK. In initial studies, we examined whether type I IFN treatment induces phosphorylation of ULK1 in IFN-sensitive cells. Treatment of different IFN-sensitive malignant hematopoietic cell lines (U937, KT-1, and U266) with human IFNβ induced phosphorylation of ULK1 at the mTORC1 phosphorylation site (Kim et al., 2011Kim J. Kundu M. Viollet B. Guan K.L. AMPK and mTOR regulate autophagy through direct phosphorylation of Ulk1.Nat. Cell Biol. 2011; 13: 132-141Crossref PubMed Scopus (4214) Google Scholar), Ser757 (Figures 1A–1C). In contrast, there was no IFNβ-dependent induction of phosphorylation of ULK1 at Ser555 (Figures 1A–1C), the amino acid residue phosphorylated by AMPK (Bach et al., 2011Bach M. Larance M. James D.E. Ramm G. The serine/threonine kinase ULK1 is a target of multiple phosphorylation events.Biochem. J. 2011; 440: 283-291Crossref PubMed Scopus (167) Google Scholar). Previous studies have established that the serine/threonine protein kinase AKT is activated downstream of PI3K (Kaur et al., 2008aKaur S. Sassano A. Joseph A.M. Majchrzak-Kita B. Eklund E.A. Verma A. Brachmann S.M. Fish E.N. Platanias L.C. Dual regulatory roles of phosphatidylinositol 3-kinase in IFN signaling.J. Immunol. 2008; 181: 7316-7323Crossref PubMed Scopus (69) Google Scholar) and mTORC2 (Kaur et al., 2012Kaur S. Sassano A. Majchrzak-Kita B. Baker D.P. Su B. Fish E.N. Platanias L.C. Regulatory effects of mTORC2 complexes in type I IFN signaling and in the generation of IFN responses.Proc. Natl. Acad. Sci. USA. 2012; 109: 7723-7728Crossref PubMed Scopus (41) Google Scholar) during engagement of the type I IFNR and regulates downstream engagement of mTORC1 (Kaur et al., 2008bKaur S. Sassano A. Dolniak B. Joshi S. Majchrzak-Kita B. Baker D.P. Hay N. Fish E.N. Platanias L.C. Role of the Akt pathway in mRNA translation of interferon-stimulated genes.Proc. Natl. Acad. Sci. USA. 2008; 105: 4808-4813Crossref PubMed Scopus (163) Google Scholar). We examined whether engagement of ULK1 in IFN-signaling requires upstream AKT activity. For this, we determined the effects of IFNβ treatment on the phosphorylation of ULK1 using Akt1/2 double-knockout (Akt1/2−/−) mouse embryonic fibroblasts (MEFs) (Peng et al., 2003Peng X.D. Xu P.Z. Chen M.L. Hahn-Windgassen A. Skeen J. Jacobs J. Sundararajan D. Chen W.S. Crawford S.E. Coleman K.G. Hay N. Dwarfism, impaired skin development, skeletal muscle atrophy, delayed bone development, and impeded adipogenesis in mice lacking Akt1 and Akt2.Genes Dev. 2003; 17: 1352-1365Crossref PubMed Scopus (645) Google Scholar). Treatment of Akt1/2+/+ MEFs with mouse IFNβ resulted in phosphorylation of ULK1 on Ser757 (Figure 1D). However, IFNβ-induced phosphorylation of ULK1 on Ser757 was defective in Akt1/2−/− MEFs (Figure 1D). In contrast, there was no IFNβ-dependent induction of phosphorylation of ULK1 at Ser555 in both Akt1/2+/+ and Akt1/2−/− MEFs (Figure 1D). Together, these data suggest that upstream AKT activity is essential for regulation of type I IFN-induced phosphorylation of ULK1 on Ser757. Our data establish that ULK1 is activated via the type I IFNR. As the generation of IFN responses depends on expression of ISGs and their protein products (Darnell et al., 1994Darnell Jr., J.E. Kerr I.M. Stark G.R. Jak-STAT pathways and transcriptional activation in response to IFNs and other extracellular signaling proteins.Science. 1994; 264: 1415-1421Crossref PubMed Scopus (4912) Google Scholar, Stark and Darnell, 2012Stark G.R. Darnell Jr., J.E. The JAK-STAT pathway at twenty.Immunity. 2012; 36: 503-514Abstract Full Text Full Text PDF PubMed Scopus (879) Google Scholar, Cheon et al., 2014Cheon H. Borden E.C. Stark G.R. Interferons and their stimulated genes in the tumor microenvironment.Semin. Oncol. 2014; 41: 156-173Abstract Full Text Full Text PDF PubMed Scopus (142) Google Scholar), we initiated studies to determine whether ULK1 controls type I IFN-dependent gene transcription. Initially, we determined whether ULK1/2 activity is required for transcriptional activation via IFN-stimulated response elements (ISRE) or IFNγ activation site (GAS) elements in luciferase reporter assays, using MEFs with targeted disruption of both the Ulk1 and Ulk2 genes. For these studies, we used Ulk1/2+/+ and Ulk1/2−/− MEFs (Cheong et al., 2011Cheong H. Lindsten T. Wu J. Lu C. Thompson C.B. Ammonia-induced autophagy is independent of ULK1/ULK2 kinases.Proc. Natl. Acad. Sci. USA. 2011; 108: 11121-11126Crossref PubMed Scopus (257) Google Scholar), as ULK1 and ULK2 kinases were previously shown to have at least partially redundant functions in fibroblasts (Kundu et al., 2008Kundu M. Lindsten T. Yang C.Y. Wu J. Zhao F. Zhang J. Selak M.A. Ney P.A. Thompson C.B. Ulk1 plays a critical role in the autophagic clearance of mitochondria and ribosomes during reticulocyte maturation.Blood. 2008; 112: 1493-1502Crossref PubMed Scopus (416) Google Scholar, Lee and Tournier, 2011Lee E.J. Tournier C. The requirement of uncoordinated 51-like kinase 1 (ULK1) and ULK2 in the regulation of autophagy.Autophagy. 2011; 7: 689-695Crossref PubMed Scopus (120) Google Scholar). IFNβ-dependent transcriptional activation via either ISRE or GAS elements was significantly reduced in the absence of Ulk1 and Ulk2 expression (Figures 2A and 2B ). To further define the role of ULK1/2 in ISG regulation, we sought to identify IFN-inducible genes differentially expressed in Ulk1/2+/+ and Ulk1/2−/− MEFs, using genome Illumina microarrays. Using principal component analysis (PCA) of differentially expressed genes, we found that the three biological replicates of gene expression profiles cluster together and that the control and IFNβ-treated Ulk1/2+/+ and Ulk1/2−/− cells represent separated groups (Figure S1A). Comparison of the transcriptomic profiles revealed IFN-inducible expression of 356 genes in Ulk1/2+/+ MEFs (Figure 2C), whereas only 264 genes were inducible in Ulk1/2−/− MEFs (Figure 2D). Notably, although 225 genes were induced in both Ulk1/2+/+ and Ulk1/2−/− MEFs (Figures 2E and 2F), the expression of 84 of these genes was significantly higher in the Ulk1/2+/+ MEFs compared to the Ulk1/2−/− MEFs (Figure 2F and Table S1, genes highlighted in red). 131 genes were found to be induced only in the Ulk1/2+/+ MEFs (Figures 2E and 2G; Table S2), whereas 39 unique genes were induced in the Ulk1/2−/− MEFs (Figures 2E and 2H; Table S3). The differentially expressed genes between Ulk1/2+/+ and Ulk1/2−/− MEFs were classified among biochemical pathways using the KEGG database (Tables S4, S5, and S6). Most of the genes whose transcriptional induction by IFNβ treatment was defective or decreased in Ulk1/2−/− MEFs could be classified among biochemical pathways that regulate adaptive and innate immunity, as well as antiviral, antiproliferative, and pro-apoptotic responses (Table S4, genes highlighted in red and green; Table S5). In contrast, genes induced by IFNβ only in Ulk1/2−/− MEFs could be classified among biochemical pathways that are involved in cell adhesion and DNA transcription (Table S6). A functional gene network, generated using IPA 2014 software, is shown in Figure S1B and demonstrates relationships among the 215 genes whose expression is defective or decreased in the absence of Ulk1/2. In further studies, we confirmed the requirement for ULK1/2 activity in the expression of several key ISGs using qRT-PCR (Figures 3A–3I). Among the genes whose expression was found defective in the absence of Ulk1/2 were Cxcl10 (Zhang et al., 2005Zhang H.M. Yuan J. Cheung P. Chau D. Wong B.W. McManus B.M. Yang D. Gamma interferon-inducible protein 10 induces HeLa cell apoptosis through a p53-dependent pathway initiated by suppression of human papillomavirus type 18 E6 and E7 expression.Mol. Cell. Biol. 2005; 25: 6247-6258Crossref PubMed Scopus (54) Google Scholar) and Eif2ak2 (García et al., 2006García M.A. Gil J. Ventoso I. Guerra S. Domingo E. Rivas C. Esteban M. Impact of protein kinase PKR in cell biology: from antiviral to antiproliferative action.Microbiol. Mol. Biol. Rev. 2006; 70: 1032-1060Crossref PubMed Scopus (583) Google Scholar, McAllister and Samuel, 2009McAllister C.S. Samuel C.E. The RNA-activated protein kinase enhances the induction of interferon-beta and apoptosis mediated by cytoplasmic RNA sensors.J. Biol. Chem. 2009; 284: 1644-1651Crossref PubMed Scopus (85) Google Scholar), both of which are involved in the induction of antiviral effects and control of apoptosis. The induction of several other genes whose function was necessary for generation for IFN biological responses was also defective in Ulk1/2−/− cells, including Irgm2 (Hunn et al., 2008Hunn J.P. Koenen-Waisman S. Papic N. Schroeder N. Pawlowski N. Lange R. Kaiser F. Zerrahn J. Martens S. Howard J.C. Regulatory interactions between IRG resistance GTPases in the cellular response to Toxoplasma gondii.EMBO J. 2008; 27: 2495-2509Crossref PubMed Scopus (118) Google Scholar), Gch1 (Rani et al., 2007Rani M.R. Shrock J. Appachi S. Rudick R.A. Williams B.R. Ransohoff R.M. Novel interferon-beta-induced gene expression in peripheral blood cells.J. Leukoc. Biol. 2007; 82: 1353-1360Crossref PubMed Scopus (39) Google Scholar, Alp and Channon, 2004Alp N.J. Channon K.M. Regulation of endothelial nitric oxide synthase by tetrahydrobiopterin in vascular disease.Arterioscler. Thromb. Vasc. Biol. 2004; 24: 413-420Crossref PubMed Scopus (430) Google Scholar), Ifit3 (Schmeisser et al., 2010Schmeisser H. Mejido J. Balinsky C.A. Morrow A.N. Clark C.R. Zhao T. Zoon K.C. Identification of alpha interferon-induced genes associated with antiviral activity in Daudi cells and characterization of IFIT3 as a novel antiviral gene.J. Virol. 2010; 84: 10671-10680Crossref PubMed Scopus (57) Google Scholar, Liu et al., 2011Liu X.Y. Chen W. Wei B. Shan Y.F. Wang C. IFN-induced TPR protein IFIT3 potentiates antiviral signaling by bridging MAVS and TBK1.J. Immunol. 2011; 187: 2559-2568Crossref PubMed Scopus (111) Google Scholar); Oasl2 (Zhu et al., 2014Zhu J. Zhang Y. Ghosh A. Cuevas R.A. Forero A. Dhar J. Ibsen M.S. Schmid-Burgk J.L. Schmidt T. Ganapathiraju M.K. et al.Antiviral activity of human OASL protein is mediated by enhancing signaling of the RIG-I RNA sensor.Immunity. 2014; 40: 936-948Abstract Full Text Full Text PDF PubMed Scopus (160) Google Scholar), Irf7 (Sharma et al., 2003Sharma S. tenOever B.R. Grandvaux N. Zhou G.P. Lin R. Hiscott J. Triggering the interferon antiviral response through an IKK-related pathway.Science. 2003; 300: 1148-1151Crossref PubMed Scopus (1324) Google Scholar, Honda et al., 2005Honda K. Yanai H. Negishi H. Asagiri M. Sato M. Mizutani T. Shimada N. Ohba Y. Takaoka A. Yoshida N. Taniguchi T. IRF-7 is the master regulator of type-I interferon-dependent immune responses.Nature. 2005; 434: 772-777Crossref PubMed Scopus (1696) Google Scholar, Colina et al., 2008Colina R. Costa-Mattioli M. Dowling R.J. Jaramillo M. Tai L.H. Breitbach C.J. Martineau Y. Larsson O. Rong L. Svitkin Y.V. et al.Translational control of the innate immune response through IRF-7.Nature. 2008; 452: 323-328Crossref PubMed Scopus (247) Google Scholar), Irf9 (Darnell et al., 1994Darnell Jr., J.E. Kerr I.M. Stark G.R. Jak-STAT pathways and transcriptional activation in response to IFNs and other extracellular signaling proteins.Science. 1994; 264: 1415-1421Crossref PubMed Scopus (4912) Google Scholar, van Boxel-Dezaire et al., 2006van Boxel-Dezaire A.H. Rani M.R. Stark G.R. Complex modulation of cell type-specific signaling in response to type I interferons.Immunity. 2006; 25: 361-372Abstract Full Text Full Text PDF PubMed Scopus (406) Google Scholar), and Isg54/Ifit2 (Yang et al., 2012Yang Z. Liang H. Zhou Q. Li Y. Chen H. Ye W. Chen D. Fleming J. Shu H. Liu Y. Crystal structure of ISG54 reveals a novel RNA binding structure and potential functional mechanisms.Cell Res. 2012; 22: 1328-1338Crossref PubMed Scopus (56) Google Scholar) (Figures 3A–3I). To determine whether ULK1 expression is required for transcriptional activation of IFN-induced genes in other cell types, studies were performed with human U937 cells in which ULK1 was knocked down using specific small interfering RNAs (siRNAs) (Figure 3J). We found decreased IFN-inducible mRNA expression of ISG15 and ISG54 (Figures 3K and 3L), genes with crucial roles in the induction of IFN responses (Lenschow et al., 2007Lenschow D.J. Lai C. Frias-Staheli N. Giannakopoulos N.V. Lutz A. Wolff T. Osiak A. Levine B. Schmidt R.E. García-Sastre A. et al.IFN-stimulated gene 15 functions as a critical antiviral molecule against influenza, herpes, and Sindbis viruses.Proc. Natl. Acad. Sci. USA. 2007; 104: 1371-1376Crossref PubMed Scopus (398) Google Scholar, Yang et al., 2012Yang Z. Liang H. Zhou Q. Li Y. Chen H. Ye W. Chen D. Fleming J. Shu H. Liu Y. Crystal structure of ISG54 reveals a novel RNA binding structure and potential functional mechanisms.Cell Res. 2012; 22: 1328-1338Crossref PubMed Scopus (56) Google Scholar), further establishing a key role for ULK1 in type I IFN signaling. It has been extensively established that ULK1 regulates the induction of autophagy (Kim et al., 2011Kim J. Kundu M. Viollet B. Guan K.L. AMPK and mTOR regulate autophagy through direct phosphorylation of Ulk1.Nat. Cell Biol. 2011; 13: 132-141Crossref PubMed Scopus (4214) Google Scholar, Russell et al., 2013Russell R.C. Tian Y. Yuan H. Park H.W. Chang Y.Y. Kim J. Kim H. Neufeld T.P. Dillin A. Guan K.L. ULK1 induces autophagy by phosphorylating Beclin-1 and activating VPS34 lipid kinase.Nat. Cell Biol. 2013; 15: 741-750Crossref PubMed Scopus (989) Google Scholar). In addition, there is also evidence for IFN-dependent induction of autophagy (Ambjørn et al., 2013Ambjørn M. Ejlerskov P. Liu Y. Lees M. Jäättelä M. Issazadeh-Navikas S. IFNB1/interferon-β-induced autophagy in MCF-7 breast cancer cells counteracts its proapoptotic function.Autophagy. 2013; 9: 287-302Crossref PubMed Scopus (56) Google Scholar, Schmeisser et al., 2014Schmeisser H. Bekisz J. Zoon K.C. New function of type I IFN: induction of autophagy.J. Interferon Cytokine Res. 2014; 34: 71-78Crossref PubMed Scopus (87) Google Scholar). We determined whether inhibition of autophagy modulates IFN-dependent transcriptional activation. The effects of siRNA-mediated knockdown of ATG5, a protein required in the early stages of autophagosome formation (Mizushima et al., 2001Mizushima N. Yamamoto A. Hatano M. Kobayashi Y. Kabeya Y. Suzuki K. Tokuhisa T. Ohsumi Y. Yoshimori T. Dissection of autophagosome formation using Apg5-deficient mouse embryonic stem cells.J. Cell Biol. 2001; 152: 657-668Crossref PubMed Scopus (1138) Google Scholar), were initially determined. No significant differences in IFN-dependent Isg15, Isg54, and Irf9 mRNA expression were observed between control cells and cells in which ATG5 was knocked down (Figures 4A–4D). Consistent with this, treatment of cells with the autophagy inhibitors chloroquine or bafilomycin A1 (Klionsky et al., 2008Klionsky D.J. Elazar Z. Seglen P.O. Rubinsztein D.C. Does bafilomycin A1 block the fusion of autophagosomes with lysosomes?.Autophagy. 2008; 4: 849-850Crossref PubMed Scopus (353) Google Scholar) did not significantly affect ISG mRNA expression (Figures 4E–4G), further establishing that ULK1 promotes type I IFN-dependent transcriptional activation of key target genes in an autophagy-independent manner. To define the mechanisms by which ULK1 activity may regulate type I IFN-dependent transcriptional activation, we examined whether it is required for activation of pathways that control type I IFN-dependent transcriptional activation of sensitive genes. As activation of Stat1 is essential for transcriptional induction of genes that contain ISRE or GAS elements in their promoters (Stark and Darnell, 2012Stark G.R. Darnell Jr., J.E. The JAK-STAT pathway at twenty.Immunity. 2012; 36: 503-514Abstract Full Text Full Text PDF PubMed Scopus (879) Google Scholar), we first determined if phosphorylation/activation of Stat1 is Ulk1/2 dependent in MEFs. IFNβ-dependent phosphorylation of Stat1 on serine 727 and tyrosine 701 was inducible in both Ulk1/2+/+ and Ulk1/2−/− MEFs (Figure 5A), indicating that the functions of ULK1/2 are not required for type I IFN-induced activation of Stat1. As Stat1 is a key type I IFN-regulated protein involved in complexes that control both ISRE- and GAS-dependent transcription, these studies suggested that the effects of ULK1/2 on type I IFN-inducible transcriptional activation are independent of modulation of the classical STAT pathways. Previous studies have demonstrated that the p38 MAPK pathway complements the function of STAT pathways and plays a critical role in type I IFN-induced transcriptional activation via both ISRE and GAS elements (Uddin et al., 1999Uddin S. Majchrzak B. Woodson J. Arunkumar P. Alsayed Y. Pine R. Young P.R. Fish E.N. Platanias L.C. Activation of the p38 mitogen-activated protein kinase by type I interferons.J. Biol. Chem. 1999; 274: 30127-30131Crossref PubMed Scopus (207) Google Scholar, Uddin et al., 2000Uddin S. Lekmine F. Sharma N. Majchrzak B. Mayer I. Young P.R. Bokoch G.M. Fish E.N. Platanias L.C. The Rac1/p38 mitogen-activated protein kinase pathway is required for interferon alpha-dependent transcriptional activation but not serine phosphorylation of Stat proteins.J. Biol. Chem. 2000; 275: 27634-27640Abstract Full Text Full Text PDF PubMed Scopus (174) Google Scholar, Li et al., 2004Li Y. Sassano A. Majchrzak B. Deb D.K. Levy D.E. Gaestel M. Nebreda A.R. Fish E.N. Platanias L.C. Role of p38alpha Map kinase in Type I interferon signaling.J. Biol. Chem. 2004; 279: 970-979Crossref PubMed Scopus (97) Google Scholar). We examined the possibility that the effects of ULK1/2 on ISG transcription are mediated by effects on p38 MAPK activity. We found that IFNβ-induced phosphorylation of p38 MAPK was substantially decreased in Ulk1/2−/− MEFs as compared to Ulk1/2+/+ MEFs (Figure 5B). Additionally, this defective p38 MAPK phosphorylation could be rescued by ectopic re-expression of wild-type ULK1 (ULK1 WT), but not a kinase-inactive ULK1 mutant (ULK1 K46I) (Egan et al., 2011Egan D.F. Shackelford D.B. Mihaylova M.M. Gelino S. Kohnz R.A. Mair W. Vasquez D.S. Joshi A. Gwinn D.M. Taylor R. et al.Phosphorylation of ULK1 (hATG1) by AMP-activated protein kinase connects energy sensing to mitophagy.Science. 2011; 331: 456-461Crossref PubMed Scopus (1731) Google Scholar) (Figure 5C). Complementation of Ulk1/2−/− MEFs with ULK1 WT also restored IFN-induced transcriptional activation via GAS elements (Figure 5D). Moreover, we found that p38α MAPK is phosphorylated by ULK1 kinase in in vitro assays (Figures 5E and S2), further suggesting that p38 MAPK mediates the regulatory effects of Ulk1 in type I IFN-dependent transcriptional activity. To define whether the defective type I IFN-dependent gene transcription seen in Ulk1/2−/− MEFs has consequences in the generation of antiviral responses by type I IFNs, the ability of mouse IFNα to protect cells from encephalomyocarditis virus (EMCV) infection was compared in Ulk1/2+/+ and Ulk1/2−/− MEFs. Ulk1/2−/− MEFs were much more sensitive to EMCV infection compared to Ulk1/2+/+ MEFs (Figure S3). Specifically, at least a 50-fold reduction in infective dose was required to induce comparable EMCV-induced cytopathic effects (CPE) in the Ulk" @default.
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• W2038771520 date "2015-04-01" @default.
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• W2038771520 title "Central Role of ULK1 in Type I Interferon Signaling" @default.
• W2038771520 cites W1523693806 @default.
• W2038771520 cites W1591054413 @default.
• W2038771520 cites W1964271390 @default.
• W2038771520 cites W1970637701 @default.
• W2038771520 cites W1973454407 @default.
• W2038771520 cites W1975924645 @default.
• W2038771520 cites W1976117598 @default.
• W2038771520 cites W1978527132 @default.
• W2038771520 cites W1982906324 @default.
• W2038771520 cites W1983919608 @default.
• W2038771520 cites W1989773068 @default.
• W2038771520 cites W1994828005 @default.
• W2038771520 cites W1998147787 @default.
• W2038771520 cites W1999211990 @default.
• W2038771520 cites W2000177767 @default.
• W2038771520 cites W2011678998 @default.
• W2038771520 cites W2016771009 @default.
• W2038771520 cites W2017010917 @default.
• W2038771520 cites W2019665042 @default.
• W2038771520 cites W2024706907 @default.
• W2038771520 cites W2025848587 @default.
• W2038771520 cites W2029275361 @default.
• W2038771520 cites W2030739472 @default.
• W2038771520 cites W2037516919 @default.
• W2038771520 cites W2038139581 @default.
• W2038771520 cites W2040653543 @default.
• W2038771520 cites W2040656353 @default.
• W2038771520 cites W2041817127 @default.
• W2038771520 cites W2044411751 @default.
• W2038771520 cites W2048246423 @default.
• W2038771520 cites W2050310145 @default.
• W2038771520 cites W2052483921 @default.
• W2038771520 cites W2054702239 @default.
• W2038771520 cites W2061348529 @default.
• W2038771520 cites W2063756127 @default.
• W2038771520 cites W2065582101 @default.
• W2038771520 cites W2070897164 @default.
• W2038771520 cites W2076801755 @default.
• W2038771520 cites W2078844752 @default.
• W2038771520 cites W2079694321 @default.
• W2038771520 cites W2084880831 @default.
• W2038771520 cites W2085258486 @default.
• W2038771520 cites W2085325045 @default.
• W2038771520 cites W2088011467 @default.
• W2038771520 cites W2088793850 @default.
• W2038771520 cites W2091018161 @default.
• W2038771520 cites W2097922857 @default.
• W2038771520 cites W2098664515 @default.
• W2038771520 cites W2103659405 @default.
• W2038771520 cites W2108002172 @default.
• W2038771520 cites W2108736984 @default.
• W2038771520 cites W2110719003 @default.
• W2038771520 cites W2112895187 @default.
• W2038771520 cites W2114683059 @default.
• W2038771520 cites W2116778443 @default.
• W2038771520 cites W2119223703 @default.
• W2038771520 cites W2124597799 @default.
• W2038771520 cites W2128402485 @default.
• W2038771520 cites W2128657750 @default.
• W2038771520 cites W2129415910 @default.
• W2038771520 cites W2137563421 @default.
• W2038771520 cites W2154164244 @default.
• W2038771520 cites W2161234475 @default.
• W2038771520 cites W2163270903 @default.
• W2038771520 cites W2169231285 @default.
• W2038771520 cites W2327797349 @default.
• W2038771520 doi "https://doi.org/10.1016/j.celrep.2015.03.056" @default.
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