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.