ID2 (Inhibitor Of DNA Binding 2, HLH Protein): ID2 is a protein that plays a regulatory role by inhibiting the binding of basic helix-loop-helix transcription factors. This inhibition is important for controlling cell differentiation and proliferation. ID2 is involved in key developmental processes such as neurogenesis, immune system development, and cellular senescence, and has also been linked to the regulation of cancer cell growth and metastasis.