(A) Stacked bar graph (left) of the total number of unique peptides detected (982) in the H + L mix plotting the percentage of no phosphorylated peptides (0P) and with single (1P), double (2P) and triple (yellow) phosphorylation. Scatter plot (right) showing the intensity of the different H/L ratio groups detected (0P, pink; 1P, blue; 2P, green; 3P, yellow). (B) Number of unique phosphopeptides with multiple phosphorylations (1P, 2P, 3P) for a number of erythrocyte transmembrane and cytoskeletal protein IDs. (C) Amino acid sequence of glycophorin C (top), red square highlights the cytoplasmic domain conserved across different species. Glycophorin C unique phosphopeptides detected (bottom), red circles point out phosphorylation sites all located in the cytoplasmic domain.