The Notch signaling pathway is a short-range communication transducer that is involved in regulating many cellular processes (proliferation, stem cell and stem cell niche maintenance, cell fate specification, differentiation, and cell death) during development and renewal of adult tissues. Notch signaling is mediated by proteolysis and does not appear to involve any secondary messengers. However, depending on cellular context, the amplitude and timing of Notch activity can be regulated by posttranslational modifications to ligands and receptors and their trafficking.