Fig. 1

Evolutionary analysis of phosphosites in mammalian GCM using bioinformatics. a Distribution of kinases for P-directed phosphosites that were more conserved in vertebrates (left) than in invertebrates (right). Invertebrates: C. elegans and Drosophila; Vertebrates: lamprey, zebrafish, Xenopus, turtle, anole, chicken, and rat. The numbers on the bottom indicate the frequency of the identified phosphopeptide. CK1, CK2, GSK-3, CDK, and MAPK were predicted by KinasePhos 2.0 against phosphosites conserved in vertebrates to be higher than each phosphoproteomics score threshold. Note that the predicted MAPK-dependent sites were consistently evolutionarily conserved in vertebrates and accounted for more than 35% of all sites. In the high-score groups (≥20 phosphopeptides), the proportion of MAPK phosphorylation sites conserved in invertebrates was markedly lower. b Comparison of vertebrates and invertebrates regarding MAPK P-directed phosphosites (left) and MAPK P-directed phosphosite genes (right). I-I: the gene has emerged since invertebrates, and the protein has conserved SP/TP residues since invertebrates; V-I: the gene has emerged since invertebrates, but the protein has conserved SP/TP residues only in vertebrates; and V-V: the gene emerged first in vertebrates, and the protein has conserved SP/TP residues within vertebrates. The P-directed phosphosites with a high score that were phosphorylated by MAPK were conserved in vertebrates as both a phosphosite and also a gene. See the text. Note that as the phosphorylation scores increased in vertebrates, vertebrate-specific genes with highly MAPK-dependent sites (≥20 phosphopeptides) increased. The number with the detected frequency for each phosphopeptide is shown at the bottom (a and b)