Protein phosphorylation is one of the most indispensable post-translational modifications (PTMs), participates in almost all of biological processes and pathways, and reversibly determines the cellular dynamics and plasticity (Linding, et al., 2007; Jin, et al., 2012; Olsen, et al., 2006; Ptacek, et al., 2005; Ptacek and Snyder, 2006; Ubersax and Ferrell, 2007). In eukaryotes, protein phosphorylation mainly occurs on a specific subset of three types of amino acids, including serine (S), threonine (T) and tyrosine (Y) residues. The identification and functional analysis of phosphorylation sites (p-sites) are fundamental to understand the molecular mechanisms and regulatory roles of protein phosphorylation in eukaryotes.