PROTEIN TYROSINE PHOSPHATASES AND FOCAL ADHESIONS

细胞内蛋白质的酪氨酸磷酸化被刺激， 影响细胞生长的几个外部因素。 其中之一是 细胞-细胞外基质粘附，通过 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-基质粘附部位， 局灶性粘连，富含磷酸酪氨酸。 焦点的组装 粘连和锚定依赖性增殖需要酪氨酸 磷酸化然而，在局灶性脑梗死中磷酸酪氨酸水平升高， 粘连与转化的表型如V-SRC的表型相关 转化细胞 这些细胞显示出非贴壁依赖性生长， 圆形细胞形态，组织不良的局灶性粘连， 细胞骨架 此外，在有丝分裂中， 与粘着斑酪氨酸磷酸化的变化一致 proteins. 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（PTP）控制的。 主要 拟议工作的目标是确定与以下方面有关的PTP： 局灶性粘连，并确定其在局灶性粘连中的功能作用 组装，锚定依赖性增殖，和周转的焦点 有丝分裂时的粘连。 使用凝胶内PTP测定，PTP共- 将鉴定与粘着斑蛋白的免疫沉淀， 克隆和功能鉴定。

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.