Rho-A is critical for osteoclast podosome organization, motility, and bone resorption
Rho-A is critical for osteoclast podosome organization, motility, and bone resorption
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DOI：
10.1074/jbc.275.16.11993
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发表时间：
2000-04-21
影响因子：
4.8
通讯作者：
Hruska, KA
中科院分区：
文献类型：
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作者：
Chellaiah, MA;Soga, N;Hruska, KA
Rho在肌动蛋白应力纤维和粘着斑的形成中起调节作用，并且还参与整合素介导的信号传导事件。为了研究Rho在α（v）β（3）/凝溶胶蛋白依赖性信号传导中的作用，将HIV-Tat肽、血凝素（HA）修饰的Rho（瓦尔-14）（组成型活性）和Rho（Asn-19）（显性阴性）转导入禽类破骨细胞。通过HA-Tat的蛋白质转导是高效的，并且90-100%的细胞被HA标记的蛋白质转导。我们在此证明Rho（瓦尔-14）转导（100 nM）刺激凝溶胶相关的磷脂酰肌醇3-激酶活性、podosome组装、应力纤维形成、破骨细胞运动性和骨吸收，模拟骨桥蛋白/α（v）β（3）对破骨细胞的刺激。Rho（瓦尔-14）转导刺激的效应具有时间依赖性。C3外切酶阻断Rho（瓦尔-14）的作用，导致足体解体、运动丧失和骨吸收抑制; Rho（Asn-19）的转导导致足体解体，阻断骨桥蛋白的刺激。这些数据表明，磷酸肌醇合成，肌动蛋白应力纤维形成，破骨细胞运动性的足状体重组，和骨吸收的整合素依赖性激活需要Rho刺激。
Rho plays a regulatory role in the formation of actin stress fibers and focal adhesions, and it is also involved in integrin-mediated signaling events. To study the role of Rho in alpha(v)beta(3)/gelsolin-dependent signaling, the HIV-Tat peptide, hemagglutinin (HA)-taffged Rho(Val-14) (constitutively active) and Rho(Asn-19) (dominant negative) were transduced into avian osteoclasts. Protein transduction by HA-Tat was highly efficient, and 90-100% of the cells were transduced with HA-tagged proteins. We demonstrate here that Rho(Val-14) transduction (100 nM) stimulated gelsolin-associated phosphatidylinositol 3-kinase activity, podosome assembly, stress fiber formation, osteoclast motility, and bone resorption, mimicking osteoclast stimulation by osteopontin/alpha(v)beta(3). The effects of Rho(Val-14) transduction stimulation was time-dependent. C3 exoenzyme blocked the effects of Rho(Val-14) and induced podosome disassembly, loss of motility, and inhibition of bone resorption, Transduction of Rho(Asn-19) produced podosome disassembly, and blocked osteopontin stimulation. These data demonstrate that integrin-dependent activation of phosphoinositide synthesis, actin stress fiber formation, podosome reorganization for osteoclast motility, and bone resorption require Rho stimulation.