Fig. (1) Basic Overview of the PTC- and SMO-associated Signalling Pathways and their Cellular Outcomes. PTC governs the activity of a pro-apoptotic pathway (red square), while SMO governs the activity of the canonical elements of the HH-pathway, including the indicated non-apoptotic cellular outcomes (blue square) and pro- and anti-apoptotic (green square) signalling pathways. HH – Hedgehog; PTC = Patched; SMO = Smoothened. Anti- and pro-apoptotic proteins (round-edged squares) are labelled green and red respectively.