Carbohydrate in the Sorting of Lutropin and Follitropin

描述(申请人提供)：人类脑下垂体、荷尔蒙促黄体生成素(L H)、卵泡刺激素(FSH)和促甲状腺激素(TH)组成了一个糖蛋白异源二聚体家族，由一个共同的α-亚基和一个激素特异性的β-亚基组成。正是独特的β亚基决定了每种激素的生物学特异性。这些蛋白质的一个关键特征是它们独特的分泌模式。黄体生成素是通过一种调节的途径释放的，即它们是由促分泌剂释放的，而卵泡刺激素主要是结构性分泌的。这些糖蛋白上的天冬酰胺连接的寡糖是激素特异性的：黄体生成素上的末端碳水化合物是硫酸盐，而FSH上的末端碳水化合物是唾液酸。这项建议的主要目标是解决糖结构对黄体生成素和卵泡刺激素的路线和分类的机械作用，特别是末端硫酸盐/唾液酸与这一过程的关系。这里讨论的问题是，末端N-连接的硫酸盐是否是一个信号，用于分类到受调控的途径，以及FSH的结构性释放与唾液酸化有关。将构建FSHbeta-LHbeta嵌合体和点突变体，以识别控制其独特分选模式的序列。已建立的GH3细胞LING将被用来筛选FSH/LH的结构特征，这些结构特征控制着调节和结构性分泌。这种细胞系来源于大鼠垂体促生长激素，含有储存小泡，对促分泌剂有反应。在GH3系中发现的人类黄体生成素和卵泡刺激素的信息变体将在缺乏内源性LHbeta和FSHbeta基因的转基因小鼠的脑垂体中表达，以试图验证组织培养数据。这些实验对于试图确定与细胞内运输有关的结构基序，特别是糖蛋白激素家族的分类和包装信号将是至关重要的。在体内改变垂体促性腺激素的路线的能力也可能代表性腺功能障碍的一个重要模型，并潜在地提供一种新的方法来检查人类生殖道中正常的和最终的病理生理事件。

DESCRIPTION (provided by applicant): The human pituitary, hormones lutropin (LH), follitropin (FSH) and thyrotropin constitute a family of glycoprotein heterodimers comprised of a common alpha-subunit and a hormone-specific beta-subunit. It is the unique beta subunit that determines the biological specificity of each hormone. A critical feature of these proteins is their unique secretory patterns. LH is released through a regulated pathway, i.e, they are released by secretagogues, whereas FSH is primarily secreted constitutively. The asparagine-linked (N) otigosaccharides on these glycoproteins are hormone specific: The terminal carbohydrate on LH is sulfate, whereas for FSH it is sialic acid. The primary objective of this proposal is to address the rote of the carbohydrate structure to the routing and sorting of LH and FSH, specifically the relationship of terminal sulfate/sialic acid to this process. The question addressed here is whether terminal N-linked sulfate is a signal for sorting to the regulated pathway and constitutive release of FSH is linked to sialylation. FSHbeta-LHbeta chimeras and point mutants will be constructed to identify sequences that govern their unique sorting patterns. The established GH3 cell ling will be used to screen the structural features in FSH/LH that govern regulated vs. constitutive secretion. This cell line, which is derived from rat pituitary somatotropes, contains storage vesicles and is responsive to secretagogues. Informative human LH and FSH variants identified in the GH3 line will be expressed in pituitaries from transgenic mice lacking the endogenous LHbeta and FSHbeta genes in an attempt to verify the tissue culture data. These experiments will be critical in attempting to define the structural motifs involved with intracellular trafficking, and specifically the sorting and packaging signals for the glycoprotein hormone family. The ability to reroute the pituitary gonadotropins m vivo could also represent an important model for gonadal dysfunction and potentially provide a novel way to examine normal and ultimately pathophysiological events in the human reproductive tract.