CBP-501, a cell-permeable calmodulin-binding peptide and a G2-abrogating drug candidate, inhibits the activity of multiple Ser216-specific kinases, such as MAPKAP-K2, C-Tak1, CHK1 and CHK2, with IC50 values of 0.9 µM, 1.4 µM 3.4 µM and 6.5 µM, respectively. CBP-501 is used for various types of cancer[1][2].