ROLE OF CELL ADHESION IN BIOLOGICAL SIGNAL TRANSDUCTION

灶性粘连(FA)是突出的跨膜病变。 培养中的许多细胞的结构。个人足协的发球将 细胞外基质(ECM)与肌动蛋白细胞骨架结合，并启动 通过整合素受体的级联信号通路。这项规定 在这些细胞信号通路中，有许多是重要的 细胞功能包括生长和分化、肿瘤发生、 伤口愈合、骨整合和矿化组织的形成 矩阵。这项研究的目的是评估蛋白质酪氨酸 可能调节酪氨酸磷酸化的磷酸酶(PTP)活性 使用PTP分析，我们证实了Maher的观察结果 (美国国家科学院院刊90：11177,1993年)悬浮液中成纤维细胞的裂解物 与贴壁成纤维细胞的裂解物相比，PTP活性升高。 为了寻找可能是黏附调节的PTP，我们已经确定了 细胞质PTP，PTPD1，在FA蛋白的免疫沉淀物中。 我们目前正在探索这种互动以及这种关系 PTP到FA。微量注射受体类型的细胞质结构域 PTP，PTP，(GST融合蛋白亚克隆由Mathew慷慨提供 华盛顿州托马斯圣路易斯大学)转化为贴壁成纤维细胞，耗尽了 FA的酪氨酸磷酸化。然而，FA的结构似乎 通过抗纽蛋白染色判断其稳定性。我们的结果表明 FAs中的酪氨酸磷酸化不仅受激酶的调节 但也通过PTP的。

Focal adhesions (FA) are prominent transmembrane structures of many cells in culture. Individual FA's serve to link the extracellular matrix (ECM) to the actin cytoskeleton, and to initiate a cascade of signalling pathways through integrin receptors. The regulation of these cellular signalling pathways is important with respect to many cellular functions including growth and differentiation, tumorigenesis, wound healing, osseointegration, and the formation of a mineralized matrix. The objective of this study was to evaluate protein tyrosine phosphatase (PTP) activity that may regulate tyrosine phosphorylation in FA's. Using a PTP assay, we have confirmed the observations of Maher (PNAS 90:11177, 1993) that lysates of fibroblasts in suspension have elevated PTP activity when compared with lysates of adherent fibroblasts. Looking for PTP's that may be adhesion regulated, we have identified the cytoplamic PTP, PTPDl, in immunoprecipitates of the FA protein paxillin. We are currently exploring this interaction and the relationship of this PTP to FA's. Microinjection of the cytoplasmic domain of a receptor-type PTP, PTP , (GST fusion protein subclone generously provided by Mathew Thomas, Wash. Univ., St. Louis) into adherent fibroblasts depleted the tyrosine phosphorylation in FA's. However, the FA structure appeared to be stable as judged by staining with anti-vinculin. Our results suggest that the tyrosine phoshorylation in FAs is regulated not only by kinases but also by PTP's.