ITAM association is suggested to free up tyrosine residues Y315 and Y319 of the interdomain facilitating their phosphorylation. This leads to recruitment of other signalling molecules and renders the enzyme catalytically active. The kinase activity is further controlled by two juxtaposed tyrosine residues in the kinase domain, Y492 and Y493, acting as negative and positive kinase activity regulators respectively (Scheme 1b). ZAP-70 overexpression and hyper-phosphorylation is linked to Chronic Lymphocytic Leukemia (CLL) highlighting the need for sensitive assays to monitor the relative abundance of the above phosphorylation sites. 39 To address this need we set out to design MIPs capable of specific capture and enrichment of these targets. Based on our stoichiometric imprinting approach we here show that MIP complements can be tailored to recognize each of the four phosphorylated and nonphosphorylated forms of the Y492/Y493 motif. These MIPs were used for direct enrichment of phosphopeptides from tryptic digests of proteins extracts from stimulated Jurkat T-cells setting new limits for the achievable precision of imprinting and its compatibility with protein phosphorylation assays in biochemistry and cell biology.