Active mutants of the human p38α mitogen-activated protein kinase

Mon Diskin, Nadav Askari, Ricardo Capone, David Engelberg, Oded Livnah*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

65 Scopus citations


Mitogen-activated protein (MAP) kinases compose a family of serine/threonine kinases that function in many signal transduction pathways and affect various cellular phenotypes. Despite the abundance of available data, the exact role of each MAP kinase is not completely defined, in part because of the inability to activate MAP kinase molecules individually and specifically. Based on activating mutations found in the yeast MAP kinase 38/ Hog1 (Bell, M., Capone, R., Pashtan, I., Levitzki, A., and Engelberg, D. (2001) J. Biol. Chem. 276, 25351-25358), we designed and constructed single and multiple mutants of human MAP kinase p38α. Single (P38 D176A, p38 F327L, and p38 F327S) and subsequent double (p38 D176A/F327L and p38 D176A/F327S) mutants acquired high intrinsic activity independent of any upstream regulation and reached levels of 10 and 25%, respectively, in reference to the dually phosphorylated wild type p38α. The active p38 mutants have retained high specificity toward p38 substrates and were inhibited by the specific p38 inhibitors SB-203580 and PD-169316. We also show that similar mutations can render p38γ active as well. Based on the available structures of p38 and ERK2, we have analyzed the p38 mutants and identified a hydrophobic core stabilized by three aromatic residues, Tyr-69, Phe-327, and Trp-337, in the vicinity of the L16 loop region. Upon activation, a segment of the L16 loop, including Phe-327, becomes disordered. Structural analysis suggests that the active p38 mutants emulate the conformational changes imposed naturally by dual phosphorylation, namely, destabilization of the hydrophobic core. Essentially, the hydrophobic core is an inherent stabilizer that maintains low basal activity level in unphosphorylated p38.

Original languageAmerican English
Pages (from-to)47040-47049
Number of pages10
JournalJournal of Biological Chemistry
Issue number45
StatePublished - 5 Nov 2004


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