ANNEXIN PHOSPHORYLATION--CAUSES AND CONSEQUENCES

膜联蛋白是一组同源的、依赖于钙离子的膜- 结合蛋白可能构成一系列不同过程的基础 在膜表面。该蛋白家族中的三个成员，膜联蛋白I (Lipocortin)、Annexin II(Calpactin)和Annexin VI(P68) 当刺激细胞分裂时，被证明经历了磷酸化 癌基因或有丝分裂原，表明这些蛋白可能在 与恶性病变相关的细胞质和细胞膜改变 转型。此外，膜联蛋白I和II已被证明是 当嗜铬细胞受到刺激时它被磷酸化 胞吐作用，提示膜联蛋白也可能控制膜融合。 分化的分泌细胞。这个项目的目标是 了解膜联蛋白磷酸化在细胞调控中的作用 功能。膜联蛋白上的磷酸化位点将被绘制出来。 磷酸化对膜联蛋白I结构的影响将是 经X-射线衍射分析确定。磷酸化的影响 膜结合、膜聚集及相关的体外研究 膜联蛋白的活性将被确定。磷酸化位点 将通过定点突变进行修饰以产生重组 磷酸化的膜联蛋白的蛋白质模型。原住民的能力 或修饰的膜联蛋白影响哺乳动物细胞将通过 将这些蛋白质导入完整或通透性的分泌细胞 和成纤维细胞。这些研究将提供对细胞 膜联蛋白调控的功能及癌基因和蛋白的作用 有丝分裂原在调节这些功能中的作用。这些知识可能会导致小说 控制与恶性相关的细胞变化的方法 转型。

The annexins are a group of homologous, calcium-dependent, membrane- binding proteins that may underlie a diverse array of processes occurring at membrane surfaces. Three members of this protein family, annexin I (lipocortin), annexin II (calpactin), and annexin VI (p68), have been shown to undergo phosphorylation when cells are stimulated to divide by oncogenes or mitogens, suggesting these proteins may play roles in cytoplasmic and membrane changes associated with malignant transformation. In addition, annexins I and II have been shown to be phosphorylated in the chromaffin cell when it is stimulated to carry out exocytosis, suggesting the annexins may also control membrane fusion in differentiated secretory cells. The goal of this project is to understand the role of annexin phosphorylation in control of cellular functions. The sites of phosphorylation on the annexins will be mapped. The effect of phosphorylation on the structure of annexin I will be determined by X-ray diffraction analysis. The effects of phosphorylation on the membrane-binding, membrane-aggregating, and related in vitro activities of the annexins will be determined. The phosphorylation sites will be modified by site-directed mutagenesis to generate recombinant protein models of the phosphorylated annexins. The ability of the native or modified annexins to influence mammalian cells will be examined by introducing these proteins into intact or permeabilized secretory cells and fibroblasts. These studies will provide insights into the cellular functions controlled by the annexins and the role of oncogenes and mitogens in regulating these functions. This knowledge may lead to novel methods of controlling cellular changes associated with malignant transformation.