The role of epsilon PKC in acute and chronic diseases: Possible pharmacological implications of its modulators

Epsilon Protein kinase C (εPCK) is a particular kinase that, when activated, is able to protect against different stress injuries and therefore has been proposed to be a potential molecular target against acute and chronic diseases. Particular attention has been focused on εPCK for its involvement in the protective mechanism of Ischemic Preconditioning (IPC), a powerful endogenous mechanism characterized by subthreshold ischemic insults able to protect organs against ischemic injury. Therefore, in the past decades several εPCK modulators have been tested with the object to emulate εPCK mediate protection. Among these the most promising, so far, has been the ΨεRACK peptide, a homologous of RACK receptor for εPKC, that when administrated can mimic its effect in the cells. However, results from studies on εPCK indicate controversial role of this kinase in different organs and diseases, such as myocardial infarct, stroke, diabetes and cancer. Therefore, in this review we provide a discussion on the function of εPCK in acute and chronic diseases and how the different activators and inhibitors have been used to modulate its activity. A better understanding of its function is still needed to definitively target εPCK as novel therapeutic strategy.