PPP1R13L and breast carcinoma: When we transfected the same CD44 mutants in MCF-7 breast cancer cells, we also noticed significantly less interaction between iASPP and CD44 mutated in the ankyrin-binding domain compared with CD44wt-iASPP interaction; however, in this cell line, no enhancement of binding of the NLS mutant and Δ320 mutant CD44 was seen (Figure 3C).