Fig 1. The interaction between EGFR (blue) and sonic hedgehog (SHH, yellow) dependent signaling according to the literature (see references in text): AKT and ERK influence the translocation of GLI proteins into the nucleus, where they function as transcription factors and steer expression of PTCH1 and HHIP (dashed edges).

Another transcriptional feedback is given in the EGFR pathway, where c-JUN/AP-1 transcribe AREG, which itself can stimulate the EGF receptor.