The Notch signaling pathway is among the most commonly used communication channels
in animal cells. Recent studies have demonstrated that this pathway is indispensable for
cells in various stages of maturation, including terminal differentiation. One main focus in
mammalian studies is the role of Notch in embryonic and postembryonic stem cell systems.
In this review, the roles of Notch signaling in various mammalian stem and early progenitor
cells are summarized.