PRKD2 and cancer: Whereas the expression level of PRKD2 is not apparently changed in cancer cells and therefore is not the determinant of the formation of the Arf6–AMAP1–PRKD2 axis, the activation of Rab5c, another small GTPase, by epidermal growth factor receptor (EGFR) signaling acts as a positive regulator of the AMAP1–PRKD2 interaction28,29.