Induction of apoptosis after expression of PYK2, a tyrosine kinase structurally related to focal adhesion kinase.
Induction of apoptosis after expression of PYK2, a tyrosine kinase structurally related to focal adhesion kinase.
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DOI：
10.1083/jcb.139.2.529
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发表时间：
1997-10-20
期刊：
影响因子：
--
通讯作者：
Parsons JT
中科院分区：
文献类型：
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作者：
Xiong W;Parsons JT
许多细胞（例如，上皮细胞）需要附着到细胞外基质（ECM）上才能存活，这是一种称为贴壁依赖性细胞存活的现象。由整合素受体介导的细胞-ECM相互作用的破坏导致细胞凋亡。粘着斑激酶（FAK），一个125-kD的蛋白酪氨酸激酶激活的整合素参与，似乎参与介导细胞的附着和生存。富脯氨酸酪氨酸激酶2（PYK 2），也称为细胞粘附激酶β（CAKβ）和相关的粘附焦点酪氨酸激酶，是FAK亚家族的第二个成员，通过细胞内钙水平升高或TNFα和UV光处理激活。然而，PYK 2的功能在很大程度上仍然未知。在这项研究中，我们发现，在大鼠和小鼠成纤维细胞中，PYK 2而不是FAK的过度表达导致细胞凋亡。利用PYK 2/FAK的一系列缺失突变体和嵌合融合蛋白，我们确定PYK 2的NH 2-末端结构域和酪氨酸激酶活性是有效诱导细胞凋亡所必需的。此外，PYK 2介导的凋亡可以通过过表达催化活性v-Src、c-Src、磷脂酰肌醇-3-激酶或Akt/蛋白激酶B来抑制。此外，它也可以通过过表达ICE或ICE样蛋白酶抑制剂crmA而不是Bcl 2来抑制。总的来说，我们的研究结果表明，PYK 2和FAK，虽然在一级结构高度同源，似乎有不同的功能; FAK是细胞生存所需的，而PYK 2诱导成纤维细胞凋亡。
Many cells (e.g., epithelial cells) require attachment to the extracellular matrix (ECM) to survive, a phenomenon known as anchorage-dependent cell survival. Disruption of the cell–ECM interactions mediated by the integrin receptors results in apoptosis. Focal adhesion kinase (FAK), a 125-kD protein tyrosine kinase activated by integrin engagement, appears to be involved in mediating cell attachment and survival. Proline-rich tyrosine kinase 2 (PYK2), also known as cellular adhesion kinase β (CAKβ) and related adhesion focal tyrosine kinase, is a second member of the FAK subfamily and is activated by an increase in intracellular calcium levels, or treatment with TNFα and UV light. However, the function of PYK2 remains largely unknown. In this study, we show that over-expression of PYK2, but not FAK, in rat and mouse fibroblasts leads to apoptotic cell death. Using a series of deletion mutants and chimeric fusion proteins of PYK2/FAK, we determined that the NH2-terminal domain and tyrosine kinase activity of PYK2 were required for the efficient induction of apoptosis. Furthermore, the apoptosis mediated by PYK2 could be suppressed by over-expressing catalytically active v-Src, c-Src, phosphatidylinositol-3-kinase, or Akt/protein kinase B. In addition, it could also be suppressed by overexpressing an ICE or ICE-like proteinase inhibitor, crmA, but not Bcl2. Collectively, our results suggest that PYK2 and FAK, albeit highly homologous in primary structure, appear to have different functions; FAK is required for cell survival, whereas PYK2 induces apoptosis in fibroblasts.