K-252a, a metabolite isolated from the culture broth of Nocardiopsis sp. K-252a, was found to exhibit an extremely potent inhibitory activity on protein kinase C. The IC50 value was 32.9 nM. K252a is a potent inhibitor of various protein kinases including Protein kinase A, Protein kinase C and Protein kinase G. It acts by competition with the ATP binding site with Ki values of 18-25 nM. K252a also acts as a specific and potent inhibitor (IC50 = 3 nM) of Trk receptors and thus selectively blocks the effects of nerve growth factor (NGF) on PC12 cells. At lower concentrations, K252a can act as a neuroprotective compound, promoting survival of primary neuronal cultures. This alkaloid induces apoptosis and cell cycle arrest by inhibiting Cdc2 and Cdc25.4 Recently, K252a was found to improve psoriasis in a SCID mouse-human skin model and to suppress referred mechanical hypersensitivity and neuropeptide up-regulation associated with acute pancreatitis.