FGF-1 SECRETION PATHWAY

FGF-1 分泌途径

• 批准号: 6296878
• 负责人: THOMAS MACIAG
• 金额: $ 18.02万
• 依托单位: AMERICAN NATIONAL RED CROSS
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-06-01 至 1999-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6296878
• 关键词: beta galactosidase; binding proteins; chemical binding; cysteine; fibroblast growth factor; fusion gene; heat; hypoxia; laboratory rabbit; molecular cloning; phosphatidylserines; protein structure function; secretion; tissue /cell culture

The heparin-binding protein, fibroblast growth factor (FGF)- 1, is a prototype member of a large family of related genes and it lacks the structural feature to direct its secretion through the endoplasmic reticulum-Golgi complex. Because FGF-1 is a potent angiogenesis factor and has been implicated as a mediator of vascular pathophysiology, the mechanism by which FGF-1 is secreted may be an important regulatory feature to control the biological activity of this protein. Thus the long term goal of this application is to define the mechanism responsible for FGF-1 secretion. We have previously shown that temperature results in the secretion of FGF-1 as a protein which is biologically inactive and fails to associate with heparin with high affinity. However, (NH4)2S04 and more recently reducing agents are able to activate the heparin-binding and biological activity of latent FGF-1. Indeed, recent mutagenesis studies with FGF-1 confirm the latter observation since a cysteine-free FGF-1 mutant is not secreted in response to temperature . In addition, we have characterized FGF-1 as a phosphatydylserine (pLS)binding protein and have implicated the function of synaptotagnin (stg), a pLS-binding protein involved in exocytotic traffic, as a potential candidate for mediating the secretion of FGF-1. Lastly, we have obtained preliminary evidence that oxidized low density lipoprotein and hypoxia are able to induce the release of FGF-1 as a heparin-binding growth factor. These data support our immediate goals and these include (i) the definition of the role of FGF-1 cysteine residues and the potential function of stg in the FGF-1 secretion pathway, (ii) the identification and characterization of intracellular factors that participate in the FGF-1 secretion pathway and (iii) determine whether alternative biological stresses such as hypoxia and profound hypoxia are able to utilize this non-conventional pathway for FGF-1 secretion. It is anticipated that these results will in ultimately contribute not only to our understanding of how FGF-1 is able to regulate angiogenesis in vivo but definition of the FGF-1 secretion pathway may also yield new insight into mechanisms by which the FGF-1 secretion pathway may be inhibited. Indeed, it has recently been possible to co- localize FGF-1 and stg using novel electrophoretic methods from the medium of FGF-1-transfected NIH 3T3 cells conditioned by heat shock and NIH 3T3 cells co-transfected with FGF-1 and antisense stg fail to release FGF-1 in response to temperature stress.

肝素结合蛋白，成纤维细胞生长因子 (FGF)-1，是一种 相关基因大家族的原型成员，它缺乏 通过内质引导其分泌的结构特征 网状结构-高尔基体复合体。因为 FGF-1 是一种有效的血管生成因子 已被认为是血管病理生理学的介质， FGF-1的分泌机制可能是一个重要的调节机制 控制该蛋白质的生物活性的特征。于是长 该应用程序的术语目标是定义负责的机制 FGF-1 分泌。我们之前已经表明，温度会导致 FGF-1 作为一种蛋白质分泌，无生物活性且失效 与肝素有高亲和力缔合。然而，(NH4)2S04 等 最近的还原剂能够激活肝素结合和 潜在 FGF-1 的生物活性。事实上，最近的诱变研究 与 FGF-1 确认后一个观察结果，因为不含半胱氨酸的 FGF-1 突变体不响应温度而分泌。此外，我们还有 FGF-1 被表征为磷脂酰丝氨酸 (pLS) 结合蛋白，并具有 涉及突触结合蛋白 (stg)（一种 pLS 结合蛋白）的功能 参与胞吐交通，作为介导的潜在候选者 FGF-1的分泌。最后，我们获得了初步证据表明 氧化低密度脂蛋白和缺氧能够诱导 释放 FGF-1 作为肝素结合生长因子。这些数据支持 我们的近期目标包括 (i) 角色的定义 FGF-1半胱氨酸残基和stg在FGF-1中的潜在功能 分泌途径，(ii) 的鉴定和表征 参与 FGF-1 分泌途径的细胞内因子 (iii) 确定是否存在其他生物应激，例如缺氧 和深度缺氧能够利用这种非常规途径 FGF-1 分泌。预计这些结果将最终 不仅有助于我们了解 FGF-1 如何调节 体内血管生成，但 FGF-1 分泌途径的定义可能 还对 FGF-1 分泌的机制产生了新的见解 途径可能被抑制。事实上，最近可以共同 使用新型电泳方法从培养基中定位 FGF-1 和 stg FGF-1 转染的 NIH 3T3 细胞经热休克和 NIH 3T3 调节 共转染 FGF-1 和反义 stg 的细胞无法释放 FGF-1 对温度应激的反应。