{"doi":"10.1016/j.jbc.2021.101240","title":"Cytokine exposure mediates transcriptional activation of the orphan nuclear receptor Nur77 in hematopoietic cells","abstract":"The orphan nuclear receptor Nur77 is an immediate-early response gene that based on tissue and cell context is implicated in a plethora of cellular processes, including proliferation, differentiation, apoptosis, metabolism, and inflammation. Nur77 has a ligand-binding pocket that is obstructed by hydrophobic side groups. Naturally occurring, cell-endogenous ligands have not been identified, and Nur77 transcriptional activity is thought to be regulated through posttranslational modification and modulation of protein levels. To determine whether Nur77 is transcriptionally active in hematopoietic cells in vivo, we used an upstream activating sequence (UAS)-GFP transgenic reporter. We found that Nur77 is transcriptionally inactive in vivo in hematopoietic cells under basal conditions, but that activation occurs following cytokine exposure by G-CSF or IL-3. We also identified a series of serine residues required for cytokine-dependent transactivation of Nur77. Moreover, a kinase inhibitor library screen and proximity labeling-based mass spectrometry identified overlapping kinase pathways that physically interacted with Nur77 and whose inhibition abrogated cytokine-induced activation of Nur77. We determined that transcriptional activation of Nur77 by G-CSF or IL-3 requires functional JAK and mTor signaling since their inhibition leads to Nur77 transcriptional inactivation. Thus, intracellular cytokine signaling networks appear to regulate Nur77 transcriptional activity in mouse hematopoietic cells. The orphan nuclear receptor Nur77 is an immediate-early response gene that based on tissue and cell context is implicated in a plethora of cellular processes, including proliferation, differentiation, apoptosis, metabolism, and inflammation. Nur77 has a ligand-binding pocket that is obstructed by hydrophobic side groups. Naturally occurring, cell-endogenous ligands have not been identified, and Nur77 transcriptional activity is thought to be regulated through posttranslational modification and modulation of protein levels. To determine whether Nur77 is transcriptionally active in hematopoietic cells in vivo, we used an upstream activating sequence (UAS)-GFP transgenic reporter. We found that Nur77 is transcriptionally inactive in vivo in hematopoietic cells under basal conditions, but that activation occurs following cytokine exposure by G-CSF or IL-3. We also identified a series of serine residues required for cytokine-dependent transactivation of Nur77. Moreover, a kinase inhibitor library screen and proximity labeling-based mass spectrometry identified overlapping kinase pathways that physically interacted with Nur77 and whose inhibition abrogated cytokine-induced activation of Nur77. We determined that transcriptional activation of Nur77 by G-CSF or IL-3 requires functional JAK and mTor signaling since their inhibition leads to Nur77 transcriptional inactivation. Thus, intracellular cytokine signaling networks appear to regulate Nur77 transcriptional activity in mouse hematopoietic cells. Nuclear receptor subfamily 4 group A member 1 (NR4A1; also termed Nur77/TR3/NGFIB) is an orphan member of the nuclear receptor superfamily. Nur77 has the typical structure of a nuclear receptor: an N-terminal transactivation domain, a conserved DNA-binding domain (DBD), and a C-terminal ligand-binding domain (LBD) with a C-terminal helix that provides ligand-dependent coactivator interactions (the AF2 domain) (1Brelivet Y. Rochel N. Moras D. Structural analysis of nuclear receptors: From isolated domains to integral proteins.Mol. Cell. Endocrinol. 2012; 348: 466-473Crossref PubMed Scopus (44) Google Scholar, 2Wu L. Chen L. Characteristics of Nur77 and its ligands as potential anticancer compounds (review).Mol. Med. Rep. 2018; 18: 4793-4801PubMed Google Scholar). The transcriptional activity of most nuclear receptors depends on the presence versus absence of small-molecule ligands (3Niu H. Fujiwara H. di Martino O. Hadwiger G. Frederick T.E. Menendez-","journal":"Journal of Biological Chemistry","year":2021,"id":205093,"datarank":0.20794415416798362,"base_score":1.3862943611198906,"endowment":1.3862943611198906,"self_citation_contribution":0.20794415416798362,"citation_network_contribution":0.0,"self_endowment_contribution":0.20794415416798362,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":3,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9575,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2021-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":276878,"name":"Haixia Niu","orcid":"0000-0001-9282-5904","position":1,"is_corresponding":false},{"id":737070,"name":"Gayla Hadwiger","orcid":"0000-0002-0970-7083","position":2,"is_corresponding":false},{"id":725560,"name":"Margaret A. Ferris","orcid":"0000-0002-0577-2523","position":3,"is_corresponding":false},{"id":18433,"name":"John S. Welch","orcid":"0000-0001-6656-3672","position":4,"is_corresponding":false},{"id":737069,"name":"Orsola di Martino","orcid":"0000-0002-7620-0290","position":0,"is_corresponding":true}],"reference_count":54,"raw_metadata":{"citation_network_status":"fetched"},"created_at":"2026-07-18T23:51:30.197308Z","pmid":"34571009","pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}