Protein phosphatase inhibitors and heat preconditioning prevent Hsp27 dephosphorylation, F‐actin disruption and deterioration of morphology in ATP‐depleted endothelial cells

FEBS Letters

Loktionova, Svetlana A.²  Kabakov, Alexander E.¹ 

[1] Medical Radiology Research Center, Obninsk 249020, Russia;Cardiology Research Center, Moscow 121552, Russia

关键词: Heat shock protein;    Actin;    Protein phosphatase;    Ischemia;    Vascular endothelial cell;    Hsp;    heat shock protein;    EC;    endothelial cells;    CCCP;    carbonyl cyanide m-chlorophenylhydrazone;    PP;    protein phosphatase;    PBS;    phosphate buffered saline;    TRITC;    tetramethylrhodamine isothiocyanate;    IEF;    isoelectric focusing;    ECL;    enhanced chemiluminescence;   

DOI  :  10.1016/S0014-5793(98)00920-X

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The vascular endothelium response to ischemic depletion of ATP was studied in vitro. Endothelial cells (EC) cultured from human aorta or umbilical vein were incubated in a glucose-free medium containing CCCP or rotenone. Such blockade of energy metabolism caused a drop in ATP, destruction of actin filaments, morphological changes, and eventually disintegration of EC monolayer within 2–2.5 h. While ATP fell and F-actin collapsed, the 27-kDa heat shock protein (Hsp27) lost basal phosphorylation and became Triton X-100-insoluble forming granules inside the cell nuclei. Protein phosphatase (PP) inhibitors (okadaic acid, cantharidin, sodium orthovanadate) did not delay the ATP decrease in energy-deprived EC but arrested both the alterations in the Hsp27 status and the changes for the worse in F-actin and cell morphology. Similarly, the Hsp27 dephosphorylation/insolubilization/granulation and the cytoskeletal and morphological disturbances resulting from lack of ATP were suppressed in heat-preconditioned (thermotolerant) cultures, this effect being sensitive to quercetin, a blocker of Hsp induction. The longer preservation of the cytosolic pool of phosphorylated Hsp27 during ATP depletion in the PP inhibitor-treated or thermotolerant EC correlated with the acquired resistance of F-actin and morphology. These data suggest that PP inhibitors as well as heat-inducible Hsp(s) can protect ischemia-stressed cells by preventing the ATP loss-provoked protein dephosphorylation and breakdown of the actin cytoskeleton.

【 授权许可】

Unknown