1). The X residue differs in each class of MAPKs: ERK incorporates a threonine–glutamic acid–tyrosine (T–E–Y) motif, JNK features a threonine–proline–tyrosine (T–P–Y) motif and p38 provides a threonine–glycine–tyrosine (T–G–Y) motif. Phosphorylation of the T–X–Y motif activates the MAPKs, allowing for phosphorylation of a particular repertoire of cytoplasmic and nuclear proteins https://gunnerrfqag.mybjjblog.com/5-easy-facts-about-pbrm1-bd2-in-8-described-33634786