Overlap of homology predicted protein models showing the active (grey) and inactive (white) zebrafish ERK2 protein structure. Phosphorylation of the dual phosphorylation site (TEY) causes structural rearrangement of the activation lip. The substitutions may cause rearrangements of intermolecular interactions between amino acids resulting in a smaller distance between the activation lip with the TEY motif and the catalytic site and facilitating autophosphorylation. The L83P site (blue) is located in α-helix C and S162D (green) in the catalytic loop, both in the active site of the kinase. The D330N (red) mutation is located in the CD-site which is a docking site for inhibitory phosphatases. The D330N substitution prevents ERK inhibitory phosphatases to bind. The atomic resolution models of zebrafish ERK2 were constructed with the zERK2 amino acid sequence (ENSAMBLE:ENSDARP00000038550) and based on three-dimensional X-ray crystallography predictions PDB:1ERK and PDB:2ERK (phosphorylated). Homology modelling was performed using free online Swiss model and models were illustrated with Chimera.