Role of paxillin in metabolic oxidative stress-induced cytoskeletal reorganization: Involvement of SAPK signal transduction pathway and PTP-PEST geneexpression

Citation
Sh. Song et al., Role of paxillin in metabolic oxidative stress-induced cytoskeletal reorganization: Involvement of SAPK signal transduction pathway and PTP-PEST geneexpression, FREE RAD B, 29(1), 2000, pp. 61-70
Citations number
34
Categorie Soggetti
Biochemistry & Biophysics
Journal title
FREE RADICAL BIOLOGY AND MEDICINE
ISSN journal
08915849 → ACNP
Volume
29
Issue
1
Year of publication
2000
Pages
61 - 70
Database
ISI
SICI code
0891-5849(20000701)29:1<61:ROPIMO>2.0.ZU;2-0
Abstract
Previous studies have shown that glucose deprivation-induced cell death is associated with apoptosis, which is characterized by cellular membrane bleb bing in multi-drug-resistant human breast carcinoma MCF-7/ADR cells. In thi s study, we investigated the mechanism of glucose deprivation-induced cytos keletal reorganization, which is known to be responsible fur the morphologi cal alterations. An increase in the formation of focal adhesion and stress fibers was observed during the early pried of glucose deprivation (1-2 h). However, a disappearance of focal adhesion complexes and a loss of stress f iber formation along with membrane blebbing were observed when glucose depr ivation continued. These alterations were delayed in MCF-7/ADR cells transf ected with bcl-2 and completely suppressed by treatment with an antioxidant , N-acetyl-L-cysteine. These results indicated that glucose deprivation-ind uced oxidative stress caused the cytoskeletal reorganization. The glucose d eprivation-induced alteration of cytoskeletal organization was further inve stigated by studying a modification of paxillin, one of the focal adhesion proteins. Immunoblotting with anti-paxillin antibody showed that the paxill in band shifted from 68 kDa to about 80 kDa during 1-4 h of glucose depriva tion. The mobility shift indicated the modification of paxillin. This possi bility was further studied by an immunoprecipitation assay with anti-paxill in/anti-phosphotyrosine antibody and phosphoamino acid analysis (PAA). The immunoprecipitation study revealed that the level of tyrosine phosphorylati on of paxillin was maintained for 2 h and then markedly decreased without a change in the total level of paxillin. The PAA study showed that paxillin is dephosphorylated on tyrosine concurrent with phosphorylation on serine/t hreonine. Expression of a dominant-negative mutant of c-Jun NH2-terminal ki nase (JNK1) suppressed glucose deprivation-induced JNK1 activation, PTP-PES T gene expression, and alteration of paxillin. Taken together, these result s suggest that the alteration of the phosphorylation/dephosphorylation of p axillin may he related to the cytoskeletal reorganization and these events are mediated by glucose deprivation-induced oxidative stress and the stress -activated protein kinase signal transduction pathway. (C) 2000 Elsevier Sc ience Inc.