PROTEIN TYROSINE PHOSPHATASES AND FOCAL ADHESIONS

细胞内蛋白酪氨酸磷酸化受 影响细胞生长的几个外部因素。其中之一是 细胞-细胞外基质黏附通过以下途径启动信号 整合素受体影响细胞骨架组装、细胞周期 进展和基因表达。细胞-底物粘连的部位， 局灶性粘连，富含磷酸酪氨酸。焦点组装 粘连和锚定依赖性增殖需要酪氨酸 磷酸化。然而，病灶中磷酸酪氨酸水平的升高 粘连与v-src等转化表型相关。 转化的细胞。这些细胞表现出与锚定无关的生长， 细胞形态呈圆形，局灶性粘连组织不良 细胞骨架。此外，有丝分裂中局灶性粘连的周转 与局灶性粘连的酪氨酸磷酸化变化相吻合 蛋白质。局灶性粘连中酪氨酸磷酸化的平衡 可能是由蛋白酪氨酸磷酸酶(PTPs)控制的。少校 拟议工作的目标是确定与以下方面相关的技术合作伙伴关系 局灶性粘连及其在局灶性粘连中的作用 病灶的组装、依赖于锚定的增殖和周转 有丝分裂过程中的粘连。使用凝胶内PTP分析，PTPS共同- 与焦点黏附蛋白的免疫沉淀将被鉴定， 克隆的，并进行了功能鉴定。

Tyrosine phosphorylation of intracellular proteins is stimulated by several external factors that influence cell growth. One of these is cell-extracellular matrix adhesion which initiates signals through integrin receptors to affect cytoskeletal assembly, cell cycle progression, and gene expression. Sites of cell-substrate adhesion, focal adhesions, are enriched in phosphotyrosine. Assembly of focal adhesions and anchorage-dependent proliferation require tyrosine phosphorylation. However, elevated levels of phosphotyrosine in focal adhesions correlate with a transformed phenotype such as that of v-src transformed cells. These cells display anchorage-independent growth, a rounded cell morphology, and poorly organized focal adhesions and cytoskeleton. In addition, the turnover of focal adhesions in mitosis coincides with changes in tyrosine phosphorylation of focal adhesion proteins. The balance of tyrosine phosphorylation in focal adhesions is likely controlled by protein tyrosine phosphatases (PTPs). The major objectives of the proposed work are to identify PTPs associated with focal adhesions and to determine their functional role in focal adhesion assembly, anchorage-dependent proliferation, and turnover of focal adhesions during mitosis. Using an in-gel PTP assay, PTPs co- immunoprecipitating with focal adhesion proteins will be identified, cloned, and functionally characterized.