TRAF2 and cervical carcinoma: For example, the study in human cervical carcinoma cell line HeLa has demonstrated that intracellular S1P produced by TNF-α-activated SphK1 specifically binds to the ubiquitin ligase TNF receptor-associated factor 2 (TRAF2) in the cytoplasm and triggers downstream molecular events ultimately resulting in the activation of NF-κB signaling, which could, at least partially, account for cytoprotective function of S1P (Figure 2) [22].