| DUSP1, recognized as mitogen-activated protein kinase phosphatase 1 (MKP-1), belongs to the dual-specificity phosphatase family that precisely inactivates MAP kinase signaling through dephosphorylation of both threonine and tyrosine residues on their activation loops. The protein features a catalytic phosphatase domain flanked by conserved motifs including the Cdc25 homology domain and a MAPK docking interface that confers substrate specificity for ERK1/2, JNK, and p38 isoforms, enabling transient cytoplasmic-nuclear shuttling upon stress induction to access nuclear MAPKs. Transcriptional activation occurs rapidly via MAPK feedback loops, CREB/ATF binding at the immediate-early promoter, and stabilization against proteasomal degradation through redox-sensitive cysteine oxidation in the active site. DUSP1 engages ERK via a D-motif-mediated dock-and-trap mechanism, sequentially hydrolyzing pThr-pTyr to terminate Raf/MEK/ERK cascades that drive AP-1 and Elk-1 dependent proliferation genes, while p38 and JNK inactivation suppresses cytokine production through ATF2/c-Jun derepression. In macrophages and fibroblasts, inducible expression curbs lipopolysaccharide-triggered TNF-α and IL-6 release by attenuating sustained JNK/p38 activity, preserving feedback inhibition to prevent cytokine storm during acute inflammation. Glucocorticoid receptor ligation enhances DUSP1 transcription synergistically with p38, amplifying anti-inflammatory resolution in airway epithelia and synovial tissues. Ubiquitous basal levels rise prominently in liver, lung, and brain under oxidative or genotoxic stress, where DUSP1 confines ERK hyperactivation to balance apoptosis thresholds. Loss of DUSP1 accelerates inflammatory pathologies like rheumatoid arthritis through unchecked JNK-mediated matrix metalloproteinase expression, and in tumorigenesis, context-dependent upregulation in prostate and colon cancers sustains ERK suppression to evade oncogene-induced senescence, whereas deficiency in hepatocellular carcinoma unleashes p38-driven growth arrest. |
Lane 1: Hela, Lane 2: Jurkat, Lane 3: Mouse brain, Lane 4: Rat brain
