The nuclear receptor 4A2 (NR4A2) (nuclear receptor subfamily 4 group A member 2) also known as nuclear receptor related 1 protein (NURR1) is a protein that in humans is encoded by the NR4A2 gene. NR4A2 is a member of the nuclear receptor family of intracellular transcription factors. NR4A2 plays a key role in the maintenance of the dopaminergic system of the brain. Heterozygous loss-of-function variants in NR4A2 cause a rare autosomal dominant condition known as NR4A2-related disorder, which is characterised by developmental delay and intellectual disability, prominent language impairment, and, in a substantial minority, epilepsy and dopa-responsive dystonia or parkinsonism. Separately, the gene has been investigated as a susceptibility factor for late-onset Parkinson's disease, but the evidence remains inconclusive. Four transcript variants encoding four distinct isoforms have been identified for this gene. Additional alternate splice variants may exist, but their full-length nature has not been determined.
Structure One investigation conducted research on the structure and found that NR4A2 does not contain a ligand-binding cavity but a patch filled with hydrophobic side chains. Non-polar amino acid residues of NR4A2's co-regulators, SMRT and NCoR, bind to this hydrophobic patch. Analysis of tertiary structure has shown that the binding surface of the ligand-binding domain is located on the grooves of the 11th and 12th alpha helices. This study also found essential structural components of this hydrophobic patch, to be the three amino acids residues, F574, F592, L593; mutation of any these three inhibits LBD activity.
Function
Dopaminergic development This protein is thought to be critical to development of the dopaminergic phenotype in the midbrain, as mice without NR4A2 are lacking expression of this phenotype. This is further confirmed by studies showing that forced NR4A2 expression in naïve precursor cells leads to complete dopaminergic phenotype gene expression. While NR4A2 is a key protein in inducing this phenotype, there are other factors required, as expressing NR4A2 in isolation fails to produce it. One of these suggested factors is winged-helix transcription factor 2 (Foxa2). Studies have found these two factors to be within the same region of developing dopaminergic neurons, and both were required to have expression for the dopaminergic phenotype.
Inflammation Research has been conducted on NR4A2's role in inflammation, and may provide important information in treating disorders caused by dopaminergic neuron disease. Inflammation in the central nervous system can result from activated microglia (macrophage analogs for the central nervous system) and other pro-inflammatory factors, such as bacterial lipopolysaccharide (LPS). LPS binds to toll-like receptors (TLR), which induces inflammatory gene expression by promoting signal-dependent transcription factors. To determine which cells are dopaminergic, experiments measured the enzyme tyrosine hydroxylase (TH), which is needed for dopamine synthesis. It has been shown that NR4A2 protects dopaminergic neurons from LPS-induced inflammation by reducing inflammatory gene expression in microglia and astrocytes. When a short hairpin RNA for NR4A2 was expressed in microglia and astrocytes, these cells produced inflammatory mediators such as TNF-alpha, nitric oxide synthase, and interleukin-1 beta (IL-1β), supporting the conclusion that reduced NR4A2 promotes inflammation and leads to cell death of dopaminergic neurons. NR4A2 interacts with the transcription factor complex NF-κB-p65 on the inflammatory gene promoters. However, NR4A2 is dependent on other factors to be able to participate in these interactions. NR4A2 needs to be sumoylated and its co-regulating factor, glycogen synthase kinase 3, needs to be phosphorylated for these interactions to occur. Sumolyated NR4A2 recruits CoREST, a complex made of several proteins that assembles chromatin remodeling enzymes. The NR4A2/CoREST complex inhibits transcription of inflammatory genes.
Clinical significance
NR4A2-related neurodevelopmental disorder Heterozygous loss-of-function variants in NR4A2 cause a distinct neurodevelopmental disorder, inherited in an autosomal dominant pattern. OMIM calls it intellectual developmental disorder with language impairment and early-onset DOPA-responsive dystonia-parkinsonism, abbreviated IDLDP. Orphanet uses a similar name, developmental delay-language impairment-dopa responsive dystonia-parkinsonism syndrome. The most recent literature also uses NR4A2-related disorder. ClinGen rates the gene-disease relationship as Definitive. The group that assessed it was the Intellectual Disability and Autism Gene Curation Expert Panel, in 2021.
Signs and symptoms A 2024 systematic review analysed 19 patients in detail and excluded multi-gene deletions. A 2025 systematic review and case series pooled 32 patients, 30 of them from 16 published studies plus two of the authors' own, with 31 unique variants and a median age of 12. In the 2024 review, 19 of 19 showed signs of developmental delay or intellectual disability, compared with 93% in the 2025 review. In the 2024 review, 14 of 19 had a language disorder, compared with 63% in the 2025 review. Separately, the 2024 review reports moderate to severe expressive and receptive impairment in "at least 42%". The "at least" is because information was unavailable in 5 of the 19. These are two different measures. In the 2024 review, 10 of 19 showed neuropsychiatric symptoms comprising aggressive behaviour, anxiety, ADHD and autism. Epilepsy was observed in 8 of 19 in the 2024 review, and recurrent seizures or epilepsy in 41% in the 2025 review. Movement disorders were present in 7 of 19 in the 2024 review, including dystonia, chorea or ataxia, compared with 31% in the 2025 review. The 2024 review considers its own figure probably an underestimate, since onset is often in late adolescence or young adulthood. That figure rises to 5 of 9 (55%) among patients over 18 and 4 of 5 (80%) in patients over 30. The 2025 review reported extra-neurological features in 47% overall, consisting of craniofacial dysmorphism in 25%, musculoskeletal anomalies in 28%, gastrointestinal anomalies in 19% and renal anomalies in 6%. Severity ranges from mild to severe, with wide phenotypic heterogeneity; the least affected have only mild deficits and attend mainstream schools.
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