Docking interactions of hematopoietic tyrosine phosphatase with MAP kinases ERK2 and p38α.

Hematopoietic tyrosine phosphatase (HePTP) regulates orthogonal MAP kinase signaling cascades by dephosphorylating both extracellular signal-regulated kinase (ERK) and p38. HePTP recognizes a docking site (D-recruitment site, DRS) on its targets using a conserved N-terminal sequence motif (D-motif). Using solution nuclear magnetic resonance spectroscopy and isothermal titration calorimetry, we compare, for the first time, the docking interactions of HePTP with ERK2 and p38α. Our results demonstrate that ERK2-HePTP interactions primarily involve the D-motif, while a contiguous region called the kinase specificity motif also plays a key role in p38α-HePTP interactions. D-Motif-DRS interactions for the two kinases, while similar overall, do show some specific differences.