DUSP8 is a dual-specificity phosphatase that negatively regulates mitogen-activated protein kinase (MAPK) signaling by dephosphorylating JNK, p38, and ERK 1. The enzyme catalyzes dephosphorylation of phosphotyrosine, phosphoserine, and phosphothreonine residues on MAPK substrates, thereby modulating cellular stress responses and signal transduction 1. Mechanistically, DUSP8 operates through substrate-specific interactions. In T cells, DUSP8 interacts with and dephosphorylates the transcriptional repressor Pur-α upon TGF-β signaling, promoting its nuclear export and IL-9 transcriptional activation 2. In the hypothalamus, DUSP8 suppresses JNK signaling to maintain glucose homeostasis and insulin sensitivity 3. DISEASE RELEVANCE: GWAS studies identified DUSP8 as a type 2 diabetes risk gene, with male-specific roles in hypothalamic insulin resistance 3. DUSP8 dysregulation contributes to allergic inflammation through enhanced IL-9-mediated Th9 responses 2, hippocampal alterations affecting spatial learning and anxiety 4, altered sucrose reward behavior 5, and glioblastoma progression through regulation of tumor vascularization 6. DUSP8 expression serves as a potential biomarker for metabolic-associated steatotic liver disease 7. DUSP8 stability is regulated by ubiquitin-mediated protein degradation 8, controlling the magnitude and duration of MAPK signaling in physiological and pathological contexts.