Special Issue on “New Advances in Cyclic AMP Signalling”—An Editorial Overview

Abstract

The cyclic nucleotides 3′,5′-adenosine monophosphate (cyclic AMP) signalling system underlies the control of many biological events and disease processes in man. Cyclic AMP is synthesised by adenylate cyclase (AC) enzymes in order to activate effector proteins and it is then degraded by phosphodiesterase (PDE) enzymes. Research in recent years has identified a range of cell-type-specific cyclic AMP effector proteins, including protein kinase A (PKA), exchange factor directly activated by cyclic AMP (EPAC), cyclic AMP responsive ion channels (CICs), and the Popeye domain containing (POPDC) proteins, which participate in different signalling mechanisms. In addition, recent advances have revealed new mechanisms of action for cyclic AMP signalling, including new effectors and new levels of compartmentalization into nanodomains, involving AKAP proteins and targeted adenylate cyclase and phosphodiesterase enzymes. This Special Issue contains 21 papers that highlight advances in our current understanding of the biology of compartmentlised cyclic AMP signalling. This ranges from issues of pathogenesis and associated molecular pathways, functional assessment of novel nanodomains, to the development of novel tool molecules and new techniques for imaging cyclic AMP compartmentilisation. This editorial aims to summarise these papers within the wider context of cyclic AMP signalling.

The In Vitro Effect of Steroid Hormones, Arachidonic Acid, and Kinases Inhibitors on Aquaporin 1, 2, 5, and 7 Gene Expression in the Porcine Uterine Luminal Epithelial Cells during the Estrous Cycle

“…A different situation was observed on days 2–4 of the estrous cycle when progesterone in combination with the H89 upregulated expression of AQP5 , while E 2 combined with two doses of H89 (1 µM and 10 µM) and AA with H89 (10 µM) increased expression of AQP7 mRNA. The PKA signaling pathway is responsible for all the cellular responses induced by the cAMP second messenger system and plays an essential role in the integration of the signaling pathway networks in cells [ 49 , 50 ]. cAMP-dependent protein kinase via the transcription factor CREB plays a role in the regulation of the cell cycle, cell proliferation, and differentiation, as well as controlling of several metabolic reproductive processes like progesterone-induced oocyte maturation [ 51 , 52 , 53 ].…”

Displacement of PKA catalytic subunit from AKAP signaling islands drives pathology in Cushing’s syndrome

“…Yet, contrary to this dogma, elegant fluorescent spectroscopy studies show that under physiological parameters cAMP accumulation occurs within nanometer-sized domains (Bock et al, 2021;Musheshe et al, 2018). The existence of cAMP nanodomains argues that the local actions of PKA, EPAC guanine-nucleotide-exchange factors, and Popeye domain-containing proteins are more intricately organized than was originally considered (Amunjela et al, 2019;Beltejar et al, 2017;Laudette et al, 2018;Viña et al, 2021;Yarwood, 2020). This also explains how the ubiquitous second messenger cAMP can simultaneously propagate distinct signaling events within the same cell.…”

Role of cAMP in Double Switch of Glucagon Secretion

“…cAMP is a ubiquitous second messenger, the activator of effector proteins involved in proliferation, differentiation, secretion, contractility etc. [ 49 ]. cAMP effector proteins involve protein kinase A (PKA), exchange factor directly activated by cyclic AMP (EPAC), cyclic AMP responsive ion channels (CICs), and the Popeye domain-containing (POPDC) proteins.…”