Mycophenolic acid exhibits immunosuppressive, antiviral, and anticancer activities. Mycophenolic acid inhibits B cell activation and decreases the number of plasmablasts in clinical subjects with systemic lupus erythmatosus (SLE). Mycophenolic acid also induces necrotic cell death in B and T lymphocytes in a Cdc42- and actin polymerization-mediated manner. In other cellular models, mycophenolic acid decreases levels of TGF-β and ROS and suppresses synthesis of extracellular matrix components, decreasing proliferation of mesangial cells. In breast cancer cells, mycophenolic acid activates peroxisome proliferator-activated receptors (PPARγ), increasing lipid accumulation and cell size and inducing cell cycle arrest. Derivatives of mycophenolic acid inhibit histone deacetylases (HDACs) and suppress tubulin polymerization. Mycophenolic acid also inhibits inosine monophosphate dehydrogenase (IMPDH), inhibiting the NAD+/NADH conversion and decreasing intracellular stores of GTP.