C16-Ceramide (N-Palmitoylsphingosine)is a sphingolipid ligand and an activator of p53 tumor suppressor. It tightly binds within the p53 DNA-binding domain with a Kd of ~ 60 nM, in close vicinity to the Box V motif. It regulates the protein ubiquitination and proteasomal degradation and also induces apoptosis in cancer cells making it a research tool for targeting human cancers.