PTOV1 and pachyonychia congenita: However, while SMRT is excluded from the nucleus by MEKK-1/MEK-1 or IKKα signaling [56,58], PTOV1 translocates to the nucleus upon stimulation with growth factors [4,16], and while SMRT is expressed at similar levels in BPZ and PC [59], PTOV1 is overexpressed in PC.