Molecular Characterization of Human Tryptophan Hydroxylase 2 (hTPH2)

描述(申请人提供)：色氨酸羟基酶(TPH)催化5-羟色胺生物合成的起始和限速步骤。因此，它与各种精神健康障碍有牵连。这个长期存在的R01的目标之一是更好地了解这种关键酶。然而，在前一个周期中，其他研究人员(以及目前的合作者)发现了这种酶的一个新变体(由一个单独的基因编码)，它负责中枢神经系统5-羟色胺的合成-TPH2。鉴于这一领域的工作到目前为止主要集中在外周酶(现在称为TPH1)上，并且考虑到中枢5-羟色胺对健康和疾病的重要性，我们建议将即将到来的更新期的重点转移到更好地理解这种新的和关键的酶。几乎对hTPH2的结构、功能和酶学一无所知。与这种新酶的发现者合作，我们已经建立了关于人TPH2(HTPH2)的重要的新的特性研究。我们坚定地致力于实现本提案中的三个具体目标。具体目标1将描述hTPH2基因自然发生的多态的功能后果。在TPH2基因被发现后的短短几年里，已经描述了七种不同的编码区多态。人们对这些氨基酸替换的后果知之甚少，这一目标将弥补我们知识中的这一差距。目标2将使用我们从酪氨酸羟基酶和hTPH1获得的数据来绘制hTPH2的活性位点。这些生化研究将为这种新的和重要的酶提供重要的功能见解。具体目标3将探索hTPH2的N端调控结构域对hTPH2的调控。这些实验将有助于我们了解5-羟色胺生物合成在健康和疾病中的动态调节。 新的hTPH2基因在三年前首次被描述。它的发现解决了5-羟色胺生物合成领域的几个重要问题。然而，我们必须建立对这种关键酶的更深层次的了解，以更好地了解它在健康和疾病中的作用，并为潜在的新药物疗法的开发提供基础。

DESCRIPTION (provided by applicant): Tryptophan hydroxylase (TPH) catalyzes the initial and rate-limiting step in the biosynthesis of serotonin. As such, it has been implicated in a variety of mental health disorders. One of the goals of this long-standing R01 has been to better understand this pivotal enzyme. However, in the midst of the preceding cycle, other investigators (and current collaborators) made the seminal discovery of a new variant of this enzyme (encoded by a separate gene) that is responsible for central nervous system serotonin synthesis - TPH2. Given that the work in this field had to this point focused on the peripheral enzyme (now termed TPH1), and given the importance of CNS serotonin to health and disease, we propose shifting the emphasis of this upcoming renewal period to better understanding this novel and pivotal enzyme. Virtually nothing is known about the structure, function, and enzymology of hTPH2. Partnering with the discoverers of this new enzyme, we have established important new characterization studies on the human TPH2 (hTPH2). We are strongly positioned to pursue three specific aims in the present proposal. Specific Aim 1 will characterize the functional consequences of naturally-occurring polymorphisms in the hTPH2 gene. In the few short years since discovery of the TPH2 gene, seven different coding region polymorphisms have been described. Little is known concerning the consequences of these amino acid substitutions and this aim will address this gap in our knowledge. Aim 2 will use data we have obtained from tyrosine hydroxylase and hTPH1 to map the active site of hTPH2. These biochemical studies will provide important functional insights into this novel and important enzyme. Specific Aim 3 will explore the regulation of hTPH2 by its N-terminal regulatory domain. These experiments will contribute to our knowledge of the dynamic regulation of serotonin biosynthesis in health and disease. The novel hTPH2 gene was first described three years ago. Its discovery resolves several important discprepancies in the field of serotonin biosynthese. However, we must establish a deeper understanding of this pivotal enzyme to better appreciate its role in health and disease and to provide a basis for potential development of novel pharmacotherapeutics.