PDE4DIP/Myomegalin as a Golgi-Centrosome Scaffold in Compartmentalized Signaling, Microtubule Organization, and...

PDE4DIP/Myomegalin was originally identified as a Golgi- and centrosome-associated protein that interacts with phosphodiesterase 4D, but subsequent work has placed it within a broader network of organelle-associated signaling and cytoskeletal regulation. This review examines PDE4DIP/Myomegalin as a coiled-coil-rich scaffold linking compartmentalized cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA) signaling, Golgi-centrosome organization, microtubule architecture, and disease-associated pathway remodeling. At the centrosome, long PDE4D-binding myomegalin forms retain PDE4D3 and restrict local PKA activity, thereby influencing Hedgehog signaling. At the Golgi, AKAP9/AKAP450 provides a major scaffold, while selected myomegalin forms support Golgi-derived microtubule organization and endoplasmic reticulum-Golgi trafficking. In KRAS-mutant colorectal cancer models, PDE4DIP promotes tumor growth and MEK inhibitor resistance through Golgi-associated NF1/RAS pathway remodeling. In non-small cell lung cancer, PDE4DIP cooperates with AKAP9 to maintain Golgi localization and stability of PKA regulatory subunit II alpha; PDE4DIP loss activates PKA/cAMP response element-binding protein signaling and suppresses tumor growth. Cardiovascular studies link myomegalin isoform 4 to sarcomeric PKA signaling, co-occurring PDE4DIP and DES variants to conduction phenotypes, and PDE4DIP dysregulation to left ventricular noncompaction-associated cellular changes, although the evidence remains context dependent. Neurological and retinal disease associations remain largely exploratory. Recent work links a PDE4DIP-AKAP9 interaction to cytoskeletal integrity and RAS-ERK/AKT signaling in podocyte injury. Overall, PDE4DIP/Myomegalin is best understood as an organelle-associated organizer whose effects depend on the experimentally reported form, binding partners, and subcellular address rather than on a single linear pathway.