Shown is a multiple sequence alignment of human ERK1, ERK2, JNK1α2, JNK2α2, JNK3α2 and p38 MAPKα (CSBP2), p38 MAPKβ, p38 MAPKγ and p38 MAPKδ. The shades of blue indicate the degree of conservation for each residue and darker shades correspond to greater conservation. Note that the first 38 n-terminal residues of JNK3α2 and a variable number of c-terminal residues on each MAP kinase are not shown.