Inhibition of thimet oligopeptidase by siRNA alters specific intracellular peptides and potentiates isoproterenol signal transduction

► Mammalian cells have a large number of intracellular peptides suggested as novel signaling molecules. ► EP24.15 inhibition by siRNA modulates both specific intracellular peptides and potentiates signal transduction in human cells. ► These data suggest a novel mechanism to regulate GPCR signal transduction.