Synergy between the pre–T cell receptor and Notch: cementing the αβ lineage choice

Notch1 signaling suppresses B cell development and promotes T lineage commitment in thymus-seeding hematopoietic progenitors. Notch1 is also activated in early T cell progenitors, but the functions of these later Notch signals have not been clearly defined. Recent studies reveal that Notch signaling is not essential for pre–T cell receptor (TCR) expression or γδ lineage choice. Rather, pre-TCR signaling enhances progenitor competitiveness for limiting Notch ligands, leading to preferential expansion of TCRβ-bearing progenitors.