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.