Integrin mechanotransduction stimulates caveolin-1 phosphorylation and recruitment of Csk to mediate actin reorganization
Integrin mechanotransduction stimulates caveolin-1 phosphorylation and recruitment of Csk to mediate actin reorganization
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DOI：
10.1152/ajpheart.00519.2004
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发表时间：
2005-02-01
影响因子：
4.8
通讯作者：
Rizzo, V
中科院分区：
文献类型：
--
作者：
Radel, C;Rizzo, V
为了确定 Caveolin-1 在整合素机械转导中的作用，我们将牛主动脉内皮细胞暴露于 10 dyn/ cm(2) 的层流剪切应力。由于 β(1)-整合素阻断抗体 JB1A 具有抑制性，Caveolin-1 在剪切作用下发生急剧且短暂的磷酸化，发生在 β(1)-整合素激活的下游。在通过敲低 Csk 或 1 型蛋白磷酸酶 (PP1) 处理来操纵 Src 家族激酶 (SFK) 活性时，我们观察到剪切诱导的 Caveolin-1 磷酸化分别协调增加和减少。因此，剪切刺激的 Caveolin-1 磷酸化受 SFK 调节。剪切诱导的 Caveolin-1 募集和磷酸化以 β(1)-整合素和 SFK 依赖性方式发生在 β(1)-整合素位点。据描述，Csk 与 pY14-caveolin-1 和整合素相互作用，在剪切后与增加的磷酸化 Caveolin-1 库结合，对应于 β(1)-整合素位点处 Csk 的升高。与 Caveolin-1 一样，JB1A 和 PP1 治疗减弱了剪切诱导的 Csk 与 β(1)-整合素的关联。通过转染 Caveolin-1 磷酸化结构域肽来测定 Csk 功能。该肽减弱了剪切诱导的 Csk 在 β(1)-整联蛋白位点的关联，以及 Csk 与桩蛋白和磷酸化 Caveolin-1 的共定位。由于整合素和 Csk 活性调节细胞骨架重组，我们评估了这种机制在剪切诱导的肌球蛋白轻链 (MLC) 磷酸化中的作用。 Csk 表达的敲低足以减少由于剪切引起的 MLC 二磷酸化。通过肽处理破坏 Csk-整合素关联也抑制了 MLC 二磷酸化反应。这些数据共同表明，剪切应力下的整合素激活会导致 SFK 调节的 Caveolin-1 磷酸化，进而介导整合素位点的 Csk 关联，在下游剪切刺激的 MLC 二磷酸化中发挥作用。
To identify the role of caveolin-1 in integrin mechanotransduction, we exposed bovine aortic endothelial cells to 10 dyn/ cm(2) of laminar shear stress. Caveolin-1 was acutely and transiently phosphorylated with shear, occurring downstream of beta(1)-integrin activation as the beta(1)-integrin blocking antibody JB1A was inhibitory. In manipulating Src family kinase (SFK) activity with knockdown of Csk or type 1 protein phosphatase (PP1) treatment, we observed coordinate increase and decrease in shear-induced caveolin-1 phosphorylation, respectively. Hence, shear-stimulated caveolin-1 phosphorylation is regulated by SFKs. Shear-induced recruitment and phosphorylation of caveolin-1 occurred at beta(1)-integrin sites in a beta(1)-integrin- and SFK-dependent manner. Csk, described to interact with pY14-caveolin-1 and integrins, bound to an increased pool of phosphorylated caveolin-1 after shear corresponding with elevated Csk at beta(1)-integrin sites. Like caveolin-1, treatment with JB1A and PP1 attenuated shear-induced Csk association with beta(1)-integrins. Csk function was assayed with transfection of a caveolin-1 phosphorylation domain peptide. The peptide attenuated shear-induced association of Csk at beta(1)-integrin sites, as well as colocalization of Csk with paxillin and phosphorylated caveolin-1. Because integrin and Csk activity regulate cytoskeletal reorganization, we evaluated the role of this mechanism in shear-induced myosin light chain (MLC) phosphorylation. Knockdown of Csk expression was sufficient to reduce MLC diphosphorylation due to shear. Disruption of Csk-integrin association by peptide treatment was also inhibitory of the MLC diphosphorylation response. Together these data indicate that integrin activation with shear stress results in SFK-regulated caveolin-1 phosphorylation that, in turn, mediates Csk association at integrin sites, where it plays a role in downstream, shear-stimulated MLC diphosphorylation.