Non-overlapping functions for Pyk2 and FAK in osteoblasts during fluid shear stress-induced mechanotransduction.
Non-overlapping functions for Pyk2 and FAK in osteoblasts during fluid shear stress-induced mechanotransduction.
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DOI：
10.1371/journal.pone.0016026
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发表时间：
2011-01-25
期刊：
影响因子：
3.7
通讯作者：
Pavalko FM
中科院分区：
文献类型：
--
作者：
Young SR;Hum JM;Rodenberg E;Turner CH;Pavalko FM
机械转导是细胞将外部机械刺激（如流体剪切应力（FSS））转化为生化变化的过程，在骨骼的维持中起着关键作用。我们已经提出，FSS在骨细胞表面的机械刺激导致独特的信号复合物的形成，称为机械小体，从细胞外基质和其他骨细胞的粘附部位发射。细胞膜黏附复合物的变形最终导致靶基因表达的改变。最近，我们报道了局灶黏附激酶（FAK）是骨细胞中fss诱导的机械转导所必需的机械体复合体的一部分。这项研究扩展了这项工作，以检查FAK家族的非受体蛋白酪氨酸激酶的第二个成员，富含脯氨酸的酪氨酸激酶2 （Pyk2）的作用，并确定其在成骨细胞机械转导中的作用。在本研究中，我们使用小鼠的成骨细胞作为我们的模型系统，并比较了Pyk2和FAK在FSS诱导的成骨细胞机械转导中的作用。我们将Pyk2+/+和Pyk2−/−原代颅骨成骨细胞暴露在短时间的振荡流体中，分析了ERK1/2的下游活化以及c-fos、环氧合酶-2和骨桥蛋白的表达。与FAK不同，液体流动诱导的机械转导不需要Pyk2，因为Pyk2+/+和Pyk2−/−成骨细胞对短时间液体流动（FF）的反应没有显著差异。相反，正如预测的那样，FAK - / -成骨细胞对FF没有反应。这些数据表明FAK和Pyk2在成骨细胞机械转导过程中发射机械信号具有不同的、非冗余的功能。此外，我们比较了在两种细胞类型中产生FF的两种方法，振荡泵法和另一种轨道平台法。我们确定，两种产生FF的方法在原代颅骨成骨细胞和永生化颅骨成骨细胞中诱导了相似的反应。
Mechanotransduction, the process by which cells convert external mechanical stimuli such as fluid shear stress (FSS) into biochemical changes, plays a critical role in maintenance of the skeleton. We have proposed that mechanical stimulation by FSS across the surfaces of bone cells results in formation of unique signaling complexes called mechanosomes that are launched from sites of adhesion with the extracellular matrix and with other bone cells. Deformation of adhesion complexes at the cell membrane ultimately results in alteration of target gene expression. Recently, we reported that focal adhesion kinase (FAK) functions as a part of a mechanosome complex that is required for FSS-induced mechanotransduction in bone cells. This study extends this work to examine the role of a second member of the FAK family of non-receptor protein tyrosine kinases, proline-rich tyrosine kinase 2 (Pyk2), and determine its role during osteoblast mechanotransduction. We use osteoblasts harvested from mice as our model system in this study and compared the contributions of Pyk2 and FAK during FSS induced mechanotransduction in osteoblasts. We exposed Pyk2+/+ and Pyk2−/− primary calvarial osteoblasts to short period of oscillatory fluid flow and analyzed downstream activation of ERK1/2, and expression of c-fos, cyclooxygenase-2 and osteopontin. Unlike FAK, Pyk2 was not required for fluid flow-induced mechanotransduction as there was no significant difference in the response of Pyk2+/+ and Pyk2−/− osteoblasts to short periods of fluid flow (FF). In contrast, and as predicted, FAK−/− osteoblasts were unable to respond to FF. These data indicate that FAK and Pyk2 have distinct, non-redundant functions in launching mechanical signals during osteoblast mechanotransduction. Additionally, we compared two methods of generating FF in both cell types, oscillatory pump method and another orbital platform method. We determined that both methods of generating FF induced similar responses in both primary calvarial osteoblasts and immortalized calvarial osteoblasts.
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DOI：
10.1016/j.bbrc.2006.02.162
发表时间：
2006-05-05
影响因子：
3.1
作者：
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