Prostaglandin-induced VASP phosphorylation controls alpha II-spectrin breakdown in apoptotic cells.

Journal article

In pathological conditions, the inflammatory mediator prostaglandin E2 (PGE2) has been shown to induce apoptosis through a cAMP-dependent pathway. However, underlying mechanisms have remained illusive. Irrespective whether apoptosis is induced by the intrinsic or extrinsic pathway, the cysteine protease caspase-3 becomes activated and cleaves many key proteins including spectrins. Cleavage of the plasma membrane-associated spectrins leads to cell shrinkage, membrane blebbing, the formation of apoptotic bodies, and irreversible cell death. Recently, we identified a novel interaction between alpha II-spectrin and vasodilator-stimulated phosphoprotein (VASP), which is abrogated by the cAMP-dependent protein kinase (PKA)-mediated phosphorylation of VASP. In the present study we investigated whether VASP binding to alpha II-spectrin affects spectrin breakdown in PGE2-induced apoptosis. PGE2 dose- and time-dependently triggered VASP phosphorylation. Following induction of apoptosis, caspase-3-mediated alpha II-spectrin breakdown and membrane blebbing were markedly delayed in wild-type as compared to VASP-deficient endothelial cells. This suggests that VASP binding to alpha II-spectrin attenuates alpha II-spectrin cleavage in apoptotic cells and that PGE2-induced VASP phosphorylation regulates this process. Our findings may therefore provide the molecular basis for PGE2-induced apoptosis in pathological events.

Authors: Benz, P; Feller, S; Sickmann, A; Walter, U; Renné, T

• Publication status: Published
• Journal: International immunopharmacology
• Volume: 8
• Issue: 2
• Pages: 319-324
• Publication date: 2008-02-01
• DOI: 10.1016/j.intimp.2007.10.004
• EISSN: 1878-1705
• ISSN: 1567-5769
• Language: English
• Keywords: Apoptosis; Phosphoproteins; Cell Adhesion Molecules; Dinoprostone; Animals; Phosphorylation; Spectrin; Caspase 3; Microfilament Proteins; Dose-Response Relationship, Drug; Mice