Activin and Inhibin Signaling and Reproduction

本项目由3个项目和2个核心组成，探索激活素、bmp、抑制素及其受体和结合蛋白在调节生殖和其他系统时的信号传导机制。Project I （Vale）最近发现了一种蛋白多糖，betaglycan，作为一种假定的抑制素共受体。该项目将研究抑制素与β多糖和激活素受体相互作用以拮抗激活素和选定的bmp的机制。此外，β多糖的生理重要性将通过免疫中和或破坏其在体外和体内的表达来测试。项目1将表征β多糖变体并寻找其他抑制素共受体。Project II （Choe）已经解决了II型受体细胞外配体结合域（ActRII- ECD）单独和与激活素类似物BMP-7的复合物的x射线晶体结构。BMP-7及其抑制结合蛋白noggin的结构也已得到解决。项目II建议阐明其他结构，包括三重复合物，包括与II型和/或I型ECDs结合的激活素或bmp，以及与ActRII和/或β多糖ECDs结合的抑制素。由于项目II提供了额外的结构信息，项目I和项目II将利用这些信息进一步表征抑制素、激活素、bmp及其受体之间的结构/功能关系。项目III （Fischer）利用与项目II密切合作获得的计算机建模和x射线结构数据来设计突变配体和受体，以测试它们对配体：受体结合相互作用的影响。激活素突变体将用于测试与II型和I型激活素受体和卵泡抑素相互作用的假设。核心A（价值）提供行政和计算机支助，评价进展情况，并协调与咨询小组和联合国儿童发展中心工作人员的相互作用。Core B （Fischer, Rivier, Choe & Vale）提供技术支持和试剂，包括针对激活素/抑制素信号分子的抗血清，并对垂体和性腺激素进行ria。该核心提供合成肽，表达和纯化重组激活素和抑制素以及包括受体成分在内的各种其他蛋白质。Core通过自动测序和质谱分析来表征天然蛋白和重组蛋白。该计划汇集了多种方法来解决围绕激活素和BMP信号及其抑制素和结合蛋白的反调节的基本问题。由于激活素、bmp和抑制素的生理和病理生理意义，这些研究应该有助于阐明控制人类生育和治疗医学疾病的潜在手段。

This Program Project, comprised of 3 Projects and 2 Cores, explores the signaling mechanisms of activins, BMPs, inhibins and their receptors and binding proteins as they modulate the reproductive and other systems. Project I (Vale) recently identified the proteoglycan, betaglycan, as a putative inhibin co-receptor. This project will investigate the mechanisms by which inhibin interacts with betaglycan and activin receptors to antagonize activin and selected BMPs. Furthermore, the physiologic importance of betaglycan will be tested by immunoneutralization or disruption of its expression in vitro and in vivo. Project I will characterize betaglycan variants and seek additional inhibin co-receptors. Project II (Choe) has solved the X-ray crystallographic structure of the type II receptor extracellular ligand-binding domain (ActRII- ECD) both alone and in a complex with the activin paralog, BMP-7. The structure of BMP-7 with its inhibitory binding protein, noggin, has also been solved. Project II proposes to elucidate additional structures, including triple complexes, comprising activins or BMPs bound to their type II and/or type I ECDs as well as inhibin bound to ActRII and/or betaglycan ECDs. As additional structural information is provided by Project II it will be used by Projects I and Ill to further characterize the structure/function relationships between inhibins, activins, BMPs and their receptors. Project III (Fischer) uses computer modeling and X-ray structure data, obtained in close collaboration with Project II, to design mutant ligands and receptors to be tested for their effects on ligand:receptor binding interactions. Activin mutants will be used to test hypotheses regarding interactions with type II and type I activin receptors and follistatin. Core A (Vale) provides administrative and computer support, evaluation of progress and coordinates interactions with the Advisory Panel and NICHD staff. Core B (Fischer, Rivier, Choe & Vale) provides technical support and reagents, including antisera towards activin/inhibin signaling molecules, and conducts RIAs for pituitary and gonadal hormones. This Core provides synthetic peptides and expresses and purifies recombinant activin and inhibin and various other proteins including receptor components. The Core characterizes native and recombinant proteins by automated sequencing and mass spectrometry. This Program brings together a diversity of approaches to address fundamental issues surrounding activin and BMP signaling and their counter-regulation by inhibin and binding proteins. Because of the physiologic and pathophysiologic significance of activins, BMPs, and inhibins, these studies should serve to illuminate potential means for the control of human fertility and management of medical disorders.