Dynamin Reduces Pyk2 Y402 Phosphorylation and Src Binding in Osteoclasts
Dynamin Reduces Pyk2 Y402 Phosphorylation and Src Binding in Osteoclasts
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DOI：
10.1128/mcb.00851-08
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发表时间：
2009-07-01
影响因子：
5.3
通讯作者：
Baron, Roland
中科院分区：
文献类型：
--
作者：
Bruzzaniti, Angela;Neff, Lynn;Baron, Roland
通过整联蛋白下游的Pyk 2-Src-Cbl复合物的信号传导有助于podosomes的组装、组织和动力学，podosomes是高度运动细胞如破骨细胞和树突细胞的瞬时粘附复合物。我们以前证明了GT3发动蛋白与足体相关，调节足体中的肌动蛋白通量，并促进破骨细胞的骨吸收。我们在这里报告，发动蛋白与Pyk 2，独立的发动蛋白的GT3活性，并减少Pyk 2 Y 402磷酸化的GTPase-dependent的方式，导致减少Src结合Pyk 2。过表达发动蛋白降低了巨噬细胞集落刺激因子和粘附诱导的Pyk 2在破骨细胞样细胞中的磷酸化，表明发动蛋白可能调节整合素和生长因子受体下游的Src-Pyk 2结合，具有重要的细胞后果。此外，催化活性Src促进动力蛋白-Pyk 2缔合，并且使动力蛋白中的特定Src磷酸化酪氨酸残基突变钝化动力蛋白诱导的Pyk 2磷酸化减少。因此，由于Src通过与磷酸化Y 402的相互作用与Pyk 2结合，我们的研究结果表明，Src通过促进动力蛋白与Pyk 2-含有复合物的结合和Pyk 2 Y 402磷酸化的动力蛋白依赖性降低来激活整合素接合和其他刺激下游的负反馈回路，最终导致Src从Pyk 2解离。
Signaling via the Pyk2-Src-Cbl complex downstream of integrins contributes to the assembly, organization, and dynamics of podosomes, which are the transient adhesion complexes of highly motile cells such as osteoclasts and dendritic cells. We previously demonstrated that the GTPase dynamin is associated with podosomes, regulates actin flux in podosomes, and promotes bone resorption by osteoclasts. We report here that dynamin associates with Pyk2, independent of dynamin's GTPase activity, and reduces Pyk2 Y402 phosphorylation in a GTPase-dependent manner, leading to decreased Src binding to Pyk2. Overexpressing dynamin decreased the macrophage colony-stimulating factor- and adhesion-induced phosphorylation of Pyk2 in osteoclastlike cells, suggesting that dynamin is likely to regulate Src-Pyk2 binding downstream of integrins and growth factor receptors with important cellular consequences. Furthermore, catalytically active Src promotes dynamin-Pyk2 association, and mutating specific Src-phosphorylated tyrosine residues in dynamin blunts the dynamin-induced decrease in Pyk2 phosphorylation. Thus, since Src binds to Pyk2 through its interaction with phospho-Y402, our results suggest that Src activates a negative-feedback loop downstream of integrin engagement and other stimuli by promoting both the binding of dynamin to Pyk2-containing complexes and the dynamin-dependent decrease in Pyk2 Y402 phosphorylation, ultimately leading to the dissociation of Src from Pyk2.