MSK2 (D41A4) XP^® Rabbit mAb #3679

Mitogen- and stress-activated protein kinase 1 (MSK1) and MSK2 are serine/threonine kinases that promote immediate early gene transcription in stress- or mitogen-induced cells (1-4,7, 8) and LPS-stimulated macrophages (9). MSK2, also known as RSKB, contains two catalytic domains and has been shown to interact directly with p38 MAP kinase (10). MSK2 is phosphorylated and activated in response to tumor necrosis factor, epidermal growth factor or phorbol ester in HeLa cells or murine embryonic fibroblasts (MEFs) in a p38- and ERK-dependent manner (8,11). Phosphorylation on residues Ser196 and Thr568 within the activation loop of both catalytic domains is required for full kinase activation (11). Both MSK1 and MSK2 contain a functional nuclear localization sequence that is sufficient and required for nuclear targeting (10). Consistent with their nuclear localization, these kinases play an important role in regulating transcriptional responses to stress and mitogens. Activation of MSK2 in HeLa cells or MEFs results in rapid phosphorylation of histone H3, HMG-14, CREB and ATF1 and acetylation of histone H3 associated with immediate early gene transcription (3,4,6,7).