**Background**
Exchange proteins directly activated by cAMP (EPAC) are a family of guanine nucleotide exchange factors that play a critical role in regulating a wide variety of intracellular processes. These proteins respond to the second messenger cAMP to modulate various signaling pathways, contributing to physiological functions across multiple organ systems. Given their involvement in diverse cellular responses, EPACs have become significant targets for pharmacological intervention in various research areas. Understanding the specific roles of EPAC1 and EPAC2 is essential for developing targeted therapies. In this context, we will introduce a potent and selective EPAC antagonist – ESI-08.
**Definition**
ESI-08 is a potent and selective EPAC antagonist that can completely inhibit the activity of both EPAC1 and EPAC2 with an IC50 value of 8.4 μM.
**In Vitro Studies**
According to the ESI-08 description, this compound selectively blocks cAMP-induced EPAC activation without inhibiting cAMP-mediated PKA activation. In terms of ESI-08 biological activity, in vitro studies demonstrated that ESI-08 at a concentration of 25 μM does not alter the activation of cAMP-induced type I and II PKA holoenzymes. This selectivity is highlighted by the fact that while ESI-08 maintains PKA activity, H89, a selective PKA inhibitor, completely blocks type I or II PKA activities. The ESI-08 formula is C20H23N3OS, with a molecular weight of 353.48. These findings indicate that ESI-08 is a highly specific tool for studying EPAC-mediated signaling pathways independently of the PKA pathway. In conclusion, ESI-08 is a potent and selective antagonist of EPAC1 and EPAC2.
Keywords
ESI-08, 301177-43-5, ESI08, ESI 08, Ras, EPAC, cAMP, EPAC1, EPAC2, exchange, proteins, Inhibitor, inhibitor, inhibit
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