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Updated: Jun 4, 2026
Spatiotemporal Subcellular Manipulation of the Microtubule Cytoskeleton in the Living Preimplantation Mouse Embryo using Photostatins
Published on: November 30, 2021
PDE4D and PDE4B function in distinct subcellular compartments in mouse embryonic fibroblasts
Brigitte E Blackman1, Kathleen Horner, Julia Heidmann
1Center for Reproductive Sciences, Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California San Francisco School of Medicine, San Francisco, California 94143, USA.
Abstract:
Signaling through cAMP regulates most cellular functions. The spatiotemporal control of cAMP is, therefore, crucial for differential regulation of specific cellular targets. Here we investigated the consequences of PDE4B or PDE4D gene ablation on cAMP signaling at a subcellular level using mouse embryonic fibroblasts. PDE4B ablation had no effect on the global or bulk cytosol accumulation of cAMP but increased both basal and hormone-dependent cAMP in a near-membrane pool. Conversely, PDE4D ablation enhanced agonist-induced cAMP accumulation in the bulk cytosol as well as at the plasma membrane. Both PDE4B and PDE4D ablation significantly modified the time course and the level of isoproterenol-induced phosphorylation of vasodilator-stimulated phosphoprotein, a membrane cytoskeletal component. A second membrane response through Toll-like receptor signaling, however, was only affected by PDE4B ablation. PDE4D but not PDE4B ablation significantly prolonged cAMP-response element-binding protein-mediated transcription. These findings demonstrate that PDE4D and PDE4B have specialized functions in mouse embryonic fibroblasts with PDE4B controlling cAMP in a discrete subdomain near the plasma membrane.
Insights
Phosphodiesterase 4B (PDE4B) and PDE4D regulate cyclic adenosine monophosphate (cAMP) signaling differently. PDE4B controls cAMP near the cell membrane, while PDE4D affects bulk cytosol cAMP levels.
Area of Science:
- Cellular biology
- Molecular signaling
- Biochemistry
Background:
- Cyclic adenosine monophosphate (cAMP) is a vital second messenger regulating diverse cellular functions.
- Precise spatiotemporal control of cAMP levels is essential for targeted cellular responses.
- Phosphodiesterases (PDEs) are key enzymes that hydrolyze cAMP, thereby modulating its signaling.
Purpose of the Study:
- To investigate the distinct roles of PDE4B and PDE4D in subcellular cAMP signaling.
- To determine the impact of PDE4B and PDE4D gene ablation on cAMP dynamics in mouse embryonic fibroblasts.
- To elucidate the specific contributions of PDE4B and PDE4D to distinct cellular signaling pathways.
Main Methods:
- Gene ablation of PDE4B or PDE4D in mouse embryonic fibroblasts.
- Measurement of cAMP levels at subcellular compartments (bulk cytosol and near-membrane pools).
- Analysis of isoproterenol-induced phosphorylation of vasodilator-stimulated phosphoprotein (VASP).
- Assessment of Toll-like receptor (TLR) signaling responses.
- Evaluation of cAMP-response element-binding protein (CREB)-mediated transcription.
Main Results:
- PDE4B ablation increased cAMP in a near-membrane pool but did not affect bulk cytosol cAMP.
- PDE4D ablation enhanced agonist-induced cAMP in both bulk cytosol and plasma membrane fractions.
- Both PDE4B and PDE4D ablation altered VASP phosphorylation kinetics.
- PDE4B ablation affected TLR signaling, whereas PDE4D ablation did not.
- PDE4D ablation, but not PDE4B ablation, prolonged CREB-mediated transcription.
Conclusions:
- PDE4B and PDE4D exhibit specialized, non-redundant functions in regulating cAMP signaling in mouse embryonic fibroblasts.
- PDE4B plays a critical role in controlling cAMP levels within a specific subdomain adjacent to the plasma membrane.
- The distinct subcellular localization of PDE4B and PDE4D dictates their specific roles in cellular signaling pathways and downstream responses.
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