ID2 is an inhibitor of differentiation protein, which, along with ID1, ID3, and ID4, plays a key role in the regulation of lineage commitment, cell fate decisions, and in the timing of differentiation during neurogenesis, lymphopoiesis, and neovascularization (angiogenesis). Overexpression of ID2 has been shown to have profound effects on T-cell development and oncogenesis. The ID proteins, induced by the bone morphogenic protein-SMAD pathway, have also been shown to collaborate with LIF to ensure that embryonic stem cells opt for self-renewal.