DDI1 (DNA-Damage Inducible 1 Homolog 1) is a protein involved in crucial cellular processes such as DNA repair, cell cycle regulation, and the ubiquitin-proteasome system. It plays a vital role in responding to DNA damage by functioning as a ubiquitin-dependent protease, aiding in the degradation of specific proteins to preserve cellular health. Due to its multifunctional roles, DDI1 is essential for protecting cells from stress and may be associated with cancer and other diseases related to DNA damage and repair.