The nuclear receptor NR4A1 is regulated by SUMO modification to induce autophagic cell death

Abstract

NR4A is a nuclear receptor protein family whose members act as sensors of cellular environment and regulate multiple processes such as metabolism, proliferation, migration, apoptosis, and autophagy. Since the ligand binding domains of these receptors have no cavity for ligand interaction, their function is most likely regulated by protein abundance and posttranslational modifications. In particular, NR4A1 is regulated by protein abundance, phosphorylation, and subcellular distribution (nuclear-cytoplasmic translocation), and acts both as a transcription factor and as a regulator of other interacting proteins. SUMOylation is a post-translational modification that can affect protein stability, transcriptional activity, alter protein-protein interactions and modify intracellular localization of target proteins. In the present study we evaluated the role of SUMOylation as a posttranslational modification that can regulate the activity of NR4A1 to induce autophagy-dependent cell death. We focused on a model potentially relevant for neuronal cell death and demonstrated that NR4A1 needs to be SUMOylated to induce autophagic cell death. We observed that a triple mutant in SUMOylation sites has reduced SUMOylation, increased transcriptional activity, altered intracellular distribution, and more importantly, its ability to induce autophagic cell death is impaired.

Cytokine exposure mediates transcriptional activation of the orphan nuclear receptor Nur77 in hematopoietic cells

“…Rather, control of its transcriptional effects has been proposed to occur through regulation of expression, protein degradation, and subcellular localization ( 37 ). In addition, multiple posttranslational modifications have been described in diverse cell types, including phosphorylation, acetylation, and SUMOylation ( 37 , 38 , 39 , 40 ). Sites of posttranslational modification have been identified in both the N-terminal transactivation domain, the DBD, and the LBD.…”

Regulation of layered T cell tolerance mechanisms by the NR4A family is essential to preserve immune homeostasis and suppress autoimmunity

“…Factors such as IL-2 supply, co-stimulatory signals on distinct APC populations, or developmental context may be instructive (62). Another possible determinant is intensity/duration/biased signal transduction downstream of the TCR itself, which may in turn guide localization of NR4As to the cytosol or nucleus via posttranslational modifications (69).…”

Selective Moonlighting Cell-Penetrating Peptides

“…All cell lines were maintained as previously described [ 14 ] in DMEM (Gibco, Waltham, MA, USA) containing 10% FBS (ThermoFisher-Gibco, Waltham, MA, USA), 5000 U penicillin/streptomycin (ThermoFisher-Invitrogen, Waltham, MA, USA) and incubated at 37 °C with 5% CO 2 . Cells were seeded at a density of 3 × 10 5 cells/well in a 6-well culture plate for Western-blot experiments and 4 × 10 5 cells/well in 12-well culture plate for peptide internalization assays.…”

“…HEK293T cells were transfected as previously described [ 14 ] with the plasmid PCSC-SP-PW-Nep (Addgene, Watertown, MA, USA), which contains the human neprilysin (MME) gene. This transfection was done with the use of the reagent polyethylenimine (PEI) according to the stable transfection procedures for adherent cells.…”