Figure 1

Frequency distribution of the count of the number of phosphorylation sites per protein. To compute the expected distribution of phosphorylation sites per protein (black circles) we assumed that that every possible STY-site becomes phosphorylated based on a constant probability p, which is independent on the number of STY sites per protein and was obtained by dividing the total number of pSTY-sites by the total number of STY positions across all proteins in the data set, p = total number_pSTY/total number_STY. With p available, the expected number of phosphorylation sites per protein was computed as E(pSTY)_x = p x Number of_SYT in protein X. The observed distribution of phosphorylation sites per proteins appears as red circles (A: Experimental phosphorylation sites; B: high-confidence predicted phosphorylation sites).