TGFB1 and colitis: Furthermore, the Notch1 ICD suppresses Ptprk expression, which is contrary to a previous report of increased PTPRK expression induced by the Notch ligand Jag in keratinocytes (Xu et al., 2015), and could indicate that tissue-specific regulation by Notch promotes metastasis (Jackstadt et al., 2019) via TGFβ and is also important for recovery from DSS-induced colitis (Okamoto et al., 2009).