DEF pocket in p38 a MAP kinase facilitates substrate selectivity and mediates autophosphorylation

Nadav Komornik ¹ Netanel Tzarum ¹ Oded Livnah ¹ David Engelberg ²

¹Wolfson Centre for Applied Structural Biology, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem
²Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem

Mitogen-activated protein kinases (MAPKs) mediate cellular responses to a wide variety of extracellular stimuli. MAPKs display high specificity in recognition of their target substrates resulting in different responses and phenotypes. In recent years, the discovery of alternative activation mechanisms of the MAPK p38α revealed a previously unknown autophosphorylation property, yet the specific mechanism is not clarified. Here we reveal the linkage between a novel docking site of p38α, named DEF site interaction pocket (DEF-pocket), and the autophosphorylation and substrate selectivity of p38α, using mutagenesis analysis and activity assays. Our results show that several point mutations in the DEF-pocket resulted in significant decrease in p38α autophosphorylation capability and differences in substrate activation indicating that the DEF-pocket plays a pivotal role in both substrate selectivity and the autophosphorylation mechanism.

DEF pocket in p38a­­­­­­­­­MAP kinase facilitates substrate selectivity and mediates autophosphorylation

DEF pocket in p38aMAP kinase facilitates substrate selectivity and mediates autophosphorylation