STRUCTURAL AND FUNCTIONAL ANALYSIS OF HUMAN IGFBP-4

描述：这项新的小额拨款申请将研究分子 胰岛素样生长因子结合蛋白-4的作用机制 抑制胰岛素样生长因子(IGF)的作用。以前的研究 来自本实验室的研究表明IGFBP-4抑制血管内皮细胞增殖 特异地阻止IGF与成骨细胞膜结合 受体。初步数据还表明，推测的序列 IGF结合所必需的区域位于Thr92和Gln114之间。 一系列精心设计的重组DNA方法将被用于 首先使用以下方法定位IGF结合序列内的IGF结合域 诱变。推测IGFBP-4的IGF结合域为 定位于该基因的可变非保守区。第二 假说认为IGFBP-4类似物抑制 成骨细胞的增殖与其对IGFS的亲和力成正比 以及它们与IGF受体竞争IGF结合的能力。 重组DNA技术，包括DNA缺失、突变和 多肽合成将用于定位IGF结合域。 目标2中描述的研究将测试生成的IGFBP-4的能力 类似物，以防止IGF与其细胞表面和纯化的受体结合。 此外，它们抑制IGF诱导的骨骼细胞增殖的能力 牢房将被确定。这些研究的完成将导致 IGFBP-4中胰岛素样生长因子结合结构域的鉴定及展望 开发新的抗IGFBP-4的IGF类似物。此外, 这些研究将为今后IGFBP-4的结构与功能研究做出贡献 这可能导致开发更强大的IGFBP-4类似物，可以 用于治疗某些癌细胞，其增殖依赖于 政府间气候变化框架的自分泌/旁分泌行为。

DESCRIPTION: This new small grant application will study the molecular mechanisms by which insulin-like growth factor binding protein-4 (IGFBP-4) inhibits the action of insulin-like growth factor (IGF). Previous studies from this laboratory indicate that IGFBP-4 inhibits the proliferation of osteoblasts by specifically preventing the binding of IGF to its membrane receptor. Preliminary data also suggest that the putative sequence essential for IGF binding is located in the region between Thr92 and Gln114. A series of well designed recombinant DNA approaches will be utilized to first localize the IGF binding domain within the IGF binding sequence using mutagenesis. It is proposed that the IGF binding domain of IGFBP-4 is localized within the variable non-conserved region of the gene. The second hypothesis proposes that the potency of IGFBP-4 analogs to inhibit osteoblast proliferation is directly proportional to their affinity for IGFs as well as their ability to compete with IGF receptor for IGF binding. Recombinant DNA techniques including DNA deletion, mutagenesis and polypeptide synthesis will be used to localize the IGF binding domain. Studies described in Aim 2 will then test the ability of resultant IGFBP-4 analogs to prevent IGF binding to its cell surface and a purified receptor. In addition, their ability to inhibit IGF-induced cell proliferation in bone cells will be determined. Completion of these studies will lead to the identification of the IGF binding domain in IGFBP-4 and to the future development of new IGF analogs that are resistant to IGFBP-4. In addition, these studies will contribute to future IGFBP-4 structure-function studies that may lead to the development of more potent IGFBP-4 analogs that can be used to treat certain cancerous cells whose proliferation is dependent on the autocrine/paracrine actions of the IGFs.