Effects of commercially available sulfonate-type anionic surfactants on calcineurin activity

Abstract

 Calcineurin (CN) is a calcium ion/calmodulin-dependent protein phosphatase that plays an important role in many cellular functions. In the immune system, CN dephosphorylates the transcription factor nuclear factor of activated T cells (NFAT), which regulates cellular immune responses by inducing the expression of cytokine genes such as IL-2 and IFN-γ. CN is also the target enzyme of the immunosuppressant drugs cyclosporine A and tacrolimus.We previously reported that linear dodecylbenzenesulfonic acid standard (C₁₂-LAS), an anionic surfactant, inhibits the phosphatase activity of bovine brain CN (bCN), rat brain CN (rCN), and recombinant human CN (rhCN) expressed in Escherichia coli.

 In this study, we examined the effects of five commercially available sulfonate-type anionic surfactants, commonly used in daily life, on rhCN and bCN. The results revealed that all surfactants inhibited the activity of both CNs, and the IC₅₀ (half maximal inhibitory concentration) values varied considerably among the compounds. Furthermore, a positive correlation was observed between the IC₅₀ values toward rhCN and bCN. These findings indicate that sulfonate-type anionic surfactants used in this study can inhibit CN activity.