Role of protein-tyrosine phosphatase SHP2 in focal adhesion kinase down-regulation during neutrophil cathepsin G-induced cardiomyocytes anoikis
Role of protein-tyrosine phosphatase SHP2 in focal adhesion kinase down-regulation during neutrophil cathepsin G-induced cardiomyocytes anoikis
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DOI：
10.1074/jbc.m513040200
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发表时间：
2006-07-14
影响因子：
4.8
通讯作者：
Sabri, Abdelkarim
中科院分区：
文献类型：
--
作者：
Rafiq, Khadija;Kolpakov, Mikhail A.;Sabri, Abdelkarim
炎症细胞及其蛋白酶有助于炎症部位的组织修复。虽然在早期阶段是有益的，但过度的炎症反应会导致细胞死亡和组织损伤。 CathepsinG（Cat. G）是一种中性粒细胞来源的丝氨酸蛋白酶，已被证明可通过 caspase-3 依赖性途径诱导新生大鼠心肌细胞脱离和失巢凋亡。然而，触发 Cat 的早期机制。 G 诱导的 caspase-3 激活尚不清楚。这项研究将粘着斑激酶 (FAK) 酪氨酸去磷酸化确定为调节 Cat 的早期机制。 G 诱导的心肌细胞失巢凋亡。 Tyr-397 处的 FAK 酪氨酸磷酸化和激酶活性在 Cat.1 后均迅速降低。 G 处理与 FAK 分别与接头蛋白和细胞骨架蛋白、p130(Cas) 和桩蛋白的关联减少相关。 Cat. 需要 FAK 降低的酪氨酸磷酸化。 G 诱导的肌细胞失巢凋亡是由于同时表达 Tyr-397 处磷酸化缺陷的 FAK 突变或用蛋白酪氨酸磷酸酶 (PTP) 抑制剂过钒酸盐预处理而导致的。 G 诱导的 FAK 酪氨酸去磷酸化、caspase-3 激活和 DNA 片段化。 PTP 激活分析表明，Cat。 G处理诱导SHP2和PTEN磷酸化增加；然而，只有 SHP2 与 FAK 形成复合物以响应 Cat。 G. 显性失活 SHP2 突变体的表达显着减弱 Cat 诱导的 FAK 酪氨酸去磷酸化。 G 并保护心肌细胞发生凋亡。相反，SHP2 表达增加会加剧 Cat. G 诱导的 FAK 酪氨酸去磷酸化和肌细胞凋亡。综合起来，这些结果表明猫。 G 诱导 SHP2 激活，导致 FAK 酪氨酸去磷酸化并促进心肌细胞失巢凋亡。
Inflammatory cells and their proteases contribute to tissue reparation at site of inflammation. Although beneficial at early stages, excessive inflammatory reaction leads to cell death and tissue damage. CathepsinG(Cat. G), a neutrophil-derived serine protease, has been shown to induce neonatal rat cardiomyocyte detachment and apoptosis by anoikis through caspase-3 dependent pathway. However the early mechanisms that trigger Cat. G-induced caspase-3 activation are not known. This study identifies focal adhesion kinase (FAK) tyrosine dephosphorylation as an early mechanism that regulates Cat. G-induced anoikis in cardiomyocytes. Both FAK tyrosine phosphorylation at Tyr-397 and kinase activity decrease rapidly upon Cat. G treatment and was associated with a decrease of FAK association with adapter and cytoskeletal proteins, p130(Cas) and paxillin, respectively. FAK-decreased tyrosine phosphorylation is required for Cat. G-induced myocyte anoikis as concurrent expression of phosphorylation-deficient FAK mutated at Tyr-397 or pretreatment with a protein-tyrosine phosphatase (PTP) inhibitor, pervanadate, blocks Cat. G-induced FAK tyrosine dephosphorylation, caspase-3 activation and DNA fragmentation. Analysis of PTPs activation shows that Cat. G treatment induces an increase of SHP2 and PTEN phosphorylation; however, only SHP2 forms a complex with FAK in response to Cat. G. Expression of dominant negative SHP2 mutant markedly attenuates FAK tyrosine dephosphorylation induced by Cat. G and protects myocytes to undergo apoptosis. In contrast, increased SHP2 expression exacerbates Cat. G-induced FAK tyrosine dephosphorylation and myocyte apoptosis. Taken together, these results show that Cat. G induces SHP2 activation that leads to FAK tyrosine dephosphorylation and promotes cardiomyocyte anoikis.