Figure 2: Schematic illustration of the effects of sphingolipids and glycosphingolipids on APP processing. Interestingly, APP processing in return affects the metabolic pathways of sphingolipids. For example, it has been shown that AICD regulates the sphingolipid de novo synthesis by decreasing the expression of the Serinepalmitoyl-CoA-Transferase (SPT) or that Aβ itself directly increases the activity of the sphingomyelin degrading enzyme Sphingomyelinase (SMase), resulting in complex regulatory cycles which are dysregulated in the case of Alzheimer’s disease.