MAP2K7 and Miyoshi myopathy: In the context of MM, the RPMI-8226 and KMM-1 cell lines, which express very low levels of GADD45β and low levels of MKK7 and are consequently unaffected by GADD45β-targeting hairpins, were completely refractory to DTP3-induced killing (Figure 2B; Figures S2G–S2I, S2K, and S5F–S5H).