Abnormal localisation and hyperclustering of (alpha)(V)(beta)(3) integrins and associated proteins in Src-deficient or tyrphostin A9-treated osteoclasts.
Abnormal localisation and hyperclustering of (alpha)(V)(beta)(3) integrins and associated proteins in Src-deficient or tyrphostin A9-treated osteoclasts.
复制标题
Src 缺陷或酪氨酸磷酸酶 A9 处理的破骨细胞中 (α)(V)(β)(3) 整联蛋白和相关蛋白的异常定位和超聚集。
作者：
P. T. Lakkakorpi;Ichiro Nakamura;M. Young.;L. Lipfert;G. Rodan;L. Dưỡng
在体内，非受体酪氨酸激酶Src被证明是破骨细胞功能所必需的。我们以前曾报道，破骨细胞中的(α)(V)(β)(3)整合素以一种依赖于Src的方式诱导黏附蛋白PYK2和适配器蛋白p130(Cas)的酪氨酸磷酸化和激活。本研究的目的是分析c-Src在(α)(V)(β)(3)整合素依赖的信号和细胞骨架分子在骨吸收过程中在破骨细胞中的募集中的作用。用从Src(-/-)小鼠或其正常仔鼠分离的成骨细胞和脾细胞共培养获得的预融合破骨细胞(POCs)发现：(1)(α)(V)(β)(3)整合素在Src(-/-)和Src(+/？)中的表达水平和配体结合亲和力相似。(2)减少了Src(-/-)POCs的黏附和铺展，(3)在Src(-/-)OCL的封闭区，微丝蛋白、F-肌动蛋白、vinculin和paxlin以及PYK2和p130(Cas)的组织缺陷，以及(4)(α)(V)(β)(3)整合素与微丝和信号蛋白一起在Src缺乏的OCL的基膜上的超级聚集。在正常的OCL中，酪氨酸激酶抑制剂Tyrphostin A9抑制肌动蛋白环的形成、骨吸收和包括c-Src在内的几种蛋白质的酪氨酸磷酸化。此外，Tyrphostin A9在破骨细胞中诱导(α)(V)(β)(3)整合素的超聚集，与在Src(-/-)OCL中观察到的相似。综上所述，这些发现表明，在吸收过程中，(α)(V)(β)(3)的正常定位及其下游效应物的募集到破骨细胞的适当间隔依赖于Src激酶的活性。
The non-receptor tyrosine kinase Src was shown to be essential for osteoclast function in vivo. We have previously reported that engagement of (alpha)(v)(beta)(3) integrin in osteoclasts induces tyrosine phosphorylation and activation of the adhesion kinase PYK2 and the adaptor protein p130(Cas) in a Src-dependent manner. The objective of this study was to analyse the role of c-Src in the (alpha)(v)(beta)(3) integrin-dependent recruitment of signalling and cytoskeletal molecules in osteoclasts during bone resorption. Using prefusion osteoclasts (pOCs) obtained from cocultures of osteoblasts and spleen cells isolated from Src(-/-) mice or their normal littermates, we found: (1) similar expression levels and ligand binding affinities of (alpha)(v)(beta)(3) integrins in Src(-/-) and Src(+/?) pOCs, (2) reduced adhesion and spreading of Src(-/-) pOCs, (3) defective organisation of the microfilament proteins, F-actin, vinculin and paxillin, and of PYK2 and p130(Cas) in the sealing zone of Src(-/-)OCLs, and (4) hyperclustering of (alpha)(v)(beta)(3) integrins together with microfilament and signalling proteins in the basal membrane of Src-deficient OCLs. In normal OCLs, the tyrosine kinase inhibitor tyrphostin A9 inhibits actin ring formation, bone resorption and tyrosine phosphorylation of several proteins, including c-Src. Furthermore, tyrphostin A9 induced similar hyperclustering of (alpha)(v)(beta)(3) integrins in osteoclasts as observed in Src(-/-) OCLs. Taken together, these findings suggest that normal localisation of (alpha)(v)(beta)(3) and recruitment of its downstream effectors to the appropriate compartments of the osteoclast during resorption depend on Src kinase activity.
DOI：
10.1038/377539a0
发表时间：
1995-01-01
期刊：
Nature (London)
影响因子：
--
作者：
Ilic, Dusko;Furuta, Tasuhide;Aizawa, Shinichi
通讯作者：
Aizawa, Shinichi