GONADAL RECEPTORS/MECHANISMS OF ACTION OF PEPTIDE HORMONES IN STEROIDOGENIC CELLS

性腺受体/肽激素在类固醇细胞中的作用机制

• 批准号: 2575604
• 负责人: M L DUFAU
• 金额: --
• 依托单位: EUNICE KENNEDY SHRIVER NATIONAL INSTITUTE OF CHILD HEALTH & HUMAN DEVELOPMENT
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/2575604
• 关键词: corticotropin releasing factor; cysteine; genetic mapping; genetic promoter element; genetic transcription; hormone receptor; hormone regulation /control mechanism; hydroxysteroid dehydrogenases; introns; isozymes; luteinizing hormone; molecular site; peptide hormone; prolactin; protein folding; protein isoforms; protein sequence; protein structure function; receptor binding; receptor expression; steroid hormone metabolism; tissue /cell culture

1) The luteinizing hormone receptor is a seven transmembrane G protein-coupled receptor with a high-affinity hormone binding site located on its N-terminal extracellular domain. Mutational studies have identified two specific classes of extracellular cysteine residues that are required for surface expression or hormone binding. All four non-conserved cysteines from exon 1 are essential for binding activity and the conserved cysteines in exon 5 and 6 (109,134) are important for hormone binding. Disulfide bonding among cysteines in exon 1, and between those of exon 5 and 6, were indicated by these studies. All but two of the eight remaining cysteines, including those in loops 1 and 2 (exons 7-11) produced defects in receptor translocation to the cell surface but not in hormone binding. Thus, the requirement of cysteine in exon 1 for hormone binding activity is not related to processing of the nascent receptor. The exon 1 cysteines, in conjuction with the N-glucosamine residue of the glycosyl chains at Asn152 and Asn173, are required for refolding of the hormone binding domain of the denatured/reduced mature receptor to its active configuration. The sugar residues are required for stabilization/acquisition of the active conformation of the mature receptor and of the nascent receptor. 2) Isolation and structural characterization of the corticotropin-releasing hormone gene included the complete mapping of its intron/exon organization and the basis of the pituitary splice variants, and the isolation of novel spliced variants of the Leydig cell CRF receptor. These studies suggest that the differences in signal transduction between pituitary and Leydig cells are not attributable to the expression of different receptor isoforms. They also provide evidence for an evolutionary link between the intronless transmembrane/ cytoplasmic module of the glycoprotein receptors and the intron-containing module of the CRF receptor. 3) Unravelling the complex structure of the prolactin receptor gene has identified promoter regions and regulatory elements involved in transcriptional activation of the tissue-specific promoters (PI-PIII). The promoter utilized in the mammary gland has been identified. 4) CYP17, the key enzyme of the androgen pathway, was found to have species and tissue-specific differences in its regulatory sequences. Such differences in the amino acid domains required for hydroxylase activity within and between species (human/bovine vs. rat) are consistent with their differential regulation of lyase activity in steroidogenic cells.

1)促黄体激素受体是一个七跨膜的G 具有高亲和力激素结合位点的蛋白偶联受体 位于其N-末端胞外区。突变研究 鉴定了两种特定类型的细胞外半胱氨酸残基， 是表面表达或激素结合所必需的。所有四 来自外显子1的非保守半胱氨酸对于结合活性是必需的 外显子5和6中的保守半胱氨酸（109，134）对于 激素结合外显子1中半胱氨酸之间的二硫键，以及 这些研究表明，外显子5和6的突变。除两 剩余的8个半胱氨酸，包括环1和2中的那些（外显子 7-11）在受体易位至细胞表面中产生缺陷， 而不是激素结合。因此，外显子1中的半胱氨酸对于 激素结合活性与新生 受体的 外显子1半胱氨酸，与N-葡糖胺结合 Asn 152和Asn 173处的糖基链残基是 变性/还原的成熟多肽的激素结合结构域的重折叠 受体到其活性构型。糖残基是必需的， 稳定/获得成熟的活性构象 受体和新生受体。2)分离和结构 促肾上腺皮质激素释放激素基因的特征包括 它的内含子/外显子组织的完整映射和基础， 垂体剪接变异体和新的剪接变异体的分离 睾丸间质细胞CRF受体。这些研究表明， 垂体和间质细胞之间的信号转导差异是 不是由于不同受体同种型的表达。 他们 也提供了无内含子基因与 糖蛋白受体的跨膜/胞质模块和 CRF受体的含内含子模块。3)解开复杂的谜团 催乳素受体基因的结构已经确定了启动子区域 和参与转录激活的调控元件， 组织特异性启动子（PI-PIII）。在乳腺癌中使用的启动子 腺已被识别。 4)CYP 17，雄激素的关键酶 途径，被发现有物种和组织特异性差异，其 调节序列 氨基酸结构域的这种差异 种内和种间羟化酶活性所需 （人/牛vs.大鼠）与其差异调节一致 类固醇生成细胞中的裂解酶活性。