The regulation and function of the Id proteins in lymphocyte development

Helix - loop - helix (HLH) proteins are essential factors for lymphocyte development and function. One class of HLH proteins, the E-proteins, regulate many aspects of lymphocyte maturation, survival, proliferation, and differentiation. E-proteins are negatively regulated by another class of HLH proteins known as the Id proteins. The Id proteins function as dominant negative inhibitors of E-proteins by inhibiting their ability to bind DNA. Here we discuss the function and regulation of the Id proteins in lymphocyte development.