AKAP -DEPENDENT INTEGRATION OF CAMP AND RSK SIGNALING REGULATES ACTIVITY-DRIVEN STRUCTURAL PLASTICITY IN HIPPOCAMPAL NEURONS

Activity-dependent structural plasticity of neurons requires precise spatial and temporal coordination of intracellular signaling pathways. Cyclic AMP (cAMP) signaling and ribosomal S6 kinases (RSKs) have both been implicated in neurite growth; however, how these pathways are integrated at defined subcellular domains to control neuronal morphology remains unclear. Here, we investigated the role of A-kinase anchoring protein mAKAPalpha (AKAP6, mAKAPα) as a molecular scaffold coordinating cAMP and RSK3 signaling in hippocampal neurons. Primary rat hippocampal neurons were depolarized using KCl stimulation. Protein interactions and signaling events within the mAKAPalpha complex were analyzed by co-immunoprecipitation and Western blotting, and neurite extension was quantified under basal conditions and following depolarization. Disruption of RSK3 targeting to AKAP6 using a dominant-negative RSK-binding domain significantly reduced neurite length under both basal and depolarized conditions. Silencing of soluble adenylyl cyclase (AC10) using AAV2-mediated shRNA impaired neurite extension at baseline and attenuated depolarization-induced neurite outgrowth. Importantly, selective disruption of AC targeting to mAKAPalpha abolished activity-driven neurite elongation without affecting basal neurite length, highlighting the requirement for localized cAMP production. These findings demonstrate that AKAP-dependent integration of cAMP and RSK signaling within the mAKAPalpha signalosome is essential for activity-driven structural plasticity in hippocampal neurons.
Research is supported by the OPUS 22 grant from the National Science Centre (NCN, Poland), grant number 507/608602/50760050