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Cleavage of the Actin-capping Protein α-Adducin at Asp-Asp-Ser-Asp633-Ala by Caspase-3 Is Preceded by Its Phosphorylation on Serine 726 in Cisplatin-induced Apoptosis of Renal Epithelial Cells
Decreased phosphorylation of focal adhesion kinase and paxillin is associated with loss of focal adhesions and stress fibers and precedes the onset of apoptosis (van de Water, B., Nagelkerke, J. F., and Stevens, J. L. (1999) J. Biol. Chem. 274, 13328â13337). The cortical actin cytoskeletal network...
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Published in: | The Journal of biological chemistry 2000-08, Vol.275 (33), p.25805 |
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Main Authors: | , , , , , , , |
Format: | Article |
Language: | English |
Online Access: | Get full text |
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Summary: | Decreased phosphorylation of focal adhesion kinase and paxillin is associated with loss of focal adhesions and stress fibers
and precedes the onset of apoptosis (van de Water, B., Nagelkerke, J. F., and Stevens, J. L. (1999) J. Biol. Chem. 274, 13328â13337). The cortical actin cytoskeletal network is also lost during apoptosis, yet little is known about the temporal
relationship between altered phosphorylation of proteins that are critical in the regulation of this network and their potential
cleavage by caspases during apoptosis. Adducins are central in the cortical actin network organization. Cisplatin caused apoptosis
of renal proximal tubular epithelial cells, which was associated with the cleavage of α-adducin into a 74-kDa fragment; this
was blocked by a general caspase inhibitor benzyloxycarbonyl-Val-Ala-Asp-fluoromethyl ketone (z-VAD-fmk). Hemagglutinin-tagged
human α-adducin was cleaved into a similar 74-kDa fragment by caspase-3 in vitro but not by caspase-6 or -7. Asp-Arg-Val-Asp 29 -Glu, Asp-Ile-Val-Asp 208 -Arg, and Asp-Asp-Ser-Asp 633 -Ala were identified as the principal caspase-3 cleavage sites; Asp-Asp-Ser-Asp 633 -Ala was key in the formation of the 74-kDa fragment. Cisplatin also caused an increased phosphorylation of α-adducin and
γ-adducin in the MARCKS domain that preceded α-adducin cleavage and was associated with loss of adducins from adherens junctions;
this was not affected by z-VAD-fmk. In conclusion, the data support a model in which increased phosphorylation of α-adducin
due to cisplatin leads to dissociation from the cytoskeleton, a situation rendered irreversible by caspase-3-mediated cleavage
of α-adducin at Asp-Asp-Ser-Asp 633 -Ala. |
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ISSN: | 0021-9258 1083-351X |
DOI: | 10.1074/jbc.M001680200 |