To test the idea that PTMs in these domains are important for regulating kinase activity, we performed two case studies: one focusing on the protein kinase domain of EGFR, a highly studied and richly annotated protein kinase that has frequent gain-of-function mutations in cancer and the other focusing on the C-terminal domains of two members of the PKC family, PRKCB (PKCβ) and PRKCQ (PKCθ), which have loss-of-function mutations in cancer. Here, PRRT2 is linked to cancer.