Figure 11.

Lysine 72 site of ERK1 is acetylated. A, Lys-72 site of ERK1 is acetylated. The doubly charged peptide was detected with a mass-to-charge ratio 646.3179, which represents an error of −3.8 ppm. The tandem mass spectrum matched the following sequence, KISPFEHQTY, indicating that the Lys-72 (highlighted in red) was acetylated; the detection of b₂ is consistent with this localization. The assignment was made with Sequest with Xcorr score of 2.1 and ΔCN score of 0.19. B, diagram of ERK1's domain structure. The numbers showed the amino acid residues of ERK1. Lysine 72, detected by mass spectrometry as an acetylated site, is indicated in a red circle. Thr-202 and Tyr-204 of the Thr-Xaa-Tyr motif, whose phosphorylation status is critical for ERK1 activity, are shown as blue triangles. The kinase domain is highlighted in light gray. Other important motifs and regions are indicated as well. C, stretch of ERK1 amino acids shows the conservation of Lys-72 in different species from mammals to nematode. The mass spectrometry-detected acetylation site Lys-72 is highlighted in red.