MAPKAPK3 (MAPK-activated protein kinase 3) is a stress-responsive serine/threonine kinase that functions as a critical regulator of cellular stress responses and inflammatory signaling. Activated by p38 MAPK following stress, MAPKAPK3 phosphorylates multiple substrates including HSP27, TTP/ZFP36, and Beclin 1 to orchestrate adaptive responses 1. In inflammatory contexts, MAPKAPK3 regulates TNF and IL-6 production post-transcriptionally by phosphorylating ARE-binding proteins like TTP, modulating mRNA stability and translation [UniProt]. The kinase also promotes starvation-induced autophagy through Beclin 1 S90 phosphorylation, a mechanism antagonized by BCL2 1. MAPKAPK3 participates in toll-like receptor signaling and macropinocytosis in dendritic cells [UniProt]. Clinically, MAPKAPK3 shows disease relevance in multiple contexts: polymorphisms in MAPKAPK3 (rs3792323) associate with interferon therapy response in hepatitis C patients, with overexpression inhibiting interferon-α-induced antiviral gene transcription 2. MAPKAPK3 autoantibodies demonstrate diagnostic potential for colorectal cancer when combined with other markers 3. Additionally, elevated MAPKAPK3 in glioma cells promotes proliferation and mobility through mRNA stabilization via the HUR/MAPKAPK3 axis 4, and HCV core protein modulates MAPKAPK3 to enhance viral IRES-mediated translation 5. MAPKAPK3 dysregulation has been implicated in diabetic wound complications 6.