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

TY - JOUR

T1 - Prostaglandin-induced VASP phosphorylation controls alpha II-spectrin breakdown in apoptotic cells

AU - Benz, Peter M

AU - Feller, Stephan M

AU - Sickmann, Albert

AU - Walter, Ulrich

AU - Renné, Thomas

PY - 2008/2/1

Y1 - 2008/2/1

N2 - 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.

AB - 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.

KW - Animals

KW - Apoptosis

KW - Caspase 3

KW - Cell Adhesion Molecules

KW - Dinoprostone

KW - Dose-Response Relationship, Drug

KW - Mice

KW - Microfilament Proteins

KW - Phosphoproteins

KW - Phosphorylation

KW - Spectrin

U2 - 10.1016/j.intimp.2007.10.004

DO - 10.1016/j.intimp.2007.10.004

M3 - SCORING: Journal article

C2 - 18182247

VL - 8

SP - 319

EP - 324

JO - INT IMMUNOPHARMACOL

JF - INT IMMUNOPHARMACOL

SN - 1567-5769

IS - 2

ER -