Urokinase-induced mitogenesis is mediated by casein kinase 2 and nucleolin
Urokinase-induced mitogenesis is mediated by casein kinase 2 and nucleolin
复制标题
DOI：
10.1016/s0960-9822(00)80116-5
复制
发表时间：
1999-12-16
期刊：
影响因子：
9.2
通讯作者：
Gulba, DC
中科院分区：
文献类型：
--
作者：
Dumler, I;Stepanova, V;Gulba, DC
背景资料：尿激酶（uPA）和尿激酶受体（uPAR）形成能够同时调节细胞周围蛋白水解、细胞表面粘附和有丝分裂的多功能系统。uPA和uPAR在定向蛋白水解中的作用已被充分确立，其在细胞内的功能最近已被许多研究阐明。uPA和uPAR的促有丝分裂作用的分子机制尚不清楚，however.Results：我们确定了可能参与uPA相关的人血管平滑肌细胞有丝分裂的机制，并证明了uPA诱导激活一个独特的信号复合物。这种复合物含有uPAR和两种额外的蛋白质，核仁素和酪蛋白激酶2，它们与细胞增殖有关。这两种蛋白质分离uPA共轭溴化氰活化琼脂糖4 B亲和层析，并确定使用纳米电喷雾质谱和免疫印迹。我们使用激光扫描和免疫电镜研究，以进一步证明核仁素和酪蛋白激酶2位于细胞表面上，它们与uPAR共定位。此外，蛋白质作为整个复合物被α-内化到细胞中。结合在体外激酶测定的免疫沉淀实验表明，特异性关联的uPAR与核仁素和酪蛋白激酶2，并揭示了uPA诱导的激活酪蛋白激酶2，这可能导致磷酸化的核仁素。阻断核仁素和酪蛋白激酶2与特定的调制器导致uPA诱导的细胞proliferation.Conclusions的抑制：我们的结论是，在人血管平滑肌细胞，uPA诱导的形成和激活的一个新发现的信号复合物，包括uPAR，核仁素，酪蛋白激酶2，这是负责uPA相关的促有丝分裂反应。该复合物不是血管平滑肌细胞的独特特征，因为它也存在于其他表达uPAR的细胞类型中。(C)1999 Elsevier Science Ltd.保留所有权利。
Background: Urokinase (uPA) and the urokinase receptor (uPAR) form a multifunctional system capable of concurrently regulating pericellular proteolysis, cell-surface adhesion, and mitogenesis. The role of uPA and uPAR in directed proteolysis is well established and its function in cellular adhesiveness has recently been clarified by numerous studies. The molecular mechanisms underlying the mitogenic effects of uPA and uPAR are still unclear, however.Results: We identified mechanisms that might participate in uPA-related mitogenesis in human vascular smooth muscle cells and demonstrated that uPA induces activation of a unique signaling complex. This complex contains uPAR and two additional proteins, nucleolin and casein kinase 2, which are implicated in cell proliferation. Both proteins were isolated by affinity chromatography on uPA-conjugated cyanogen-bromide-activated Sepharose 4B and were identified using nano-electrospray mass spectrometry and immunoblotting. We used laser scanning and immunoelectron microscopy studies to further demonstrate that nucleolin and casein kinase 2 are located on the cell surface where they colocalize with the uPAR. Moreover, the proteins were cc-internalized into the cell as an entire complex. Immunoprecipitation experiments in combination with an in vitro kinase assay demonstrated a specific association of uPAR with nucleolin and casein kinase 2 and revealed a uPA-induced activation of casein kinase 2, which presumably led to phosphorylation of nucleolin. Blockade of nucleolin and casein kinase 2 with specific modulators led to the inhibition of uPA-induced cell proliferation.Conclusions: We conclude that in human vascular smooth muscle cells, uPA induces the formation and activation of a newly identified signaling complex comprising uPAR, nucleolin, and casein kinase 2, that is responsible for the uPA-related mitogenic response. The complex is not a unique feature of vascular smooth muscle cells, as it was also found in other uPAR-expressing cell types. (C) 1999 Elsevier Science Ltd. All rights reserved.