Figure 6.

Working model. AHCYL1 senses the intracellular SAH to control autophagy. SAH enhances the interaction between AHCYL1 and PIK3C3, which is mediated by the N terminus of AHCYL1 and the catalytic domain of PIK3C3, leading to inhibition of PIK3C3 activity. When cells are in presence of SAH, the enhanced interaction suppresses the production of PtdIns3P, which blocks the autophagy initiation. When in the absence of SAH, the decreased interaction releases PIK3C3 to produce PtdIns3P, eventually promotes autophagy.