Role of sulfhydration on the functions of the microtubule associated protein, Tau

项目摘要 硫化氢（H2S）是一种具有神经保护作用的气体信号分子。生成H2S 通过反向转硫途径从半胱氨酸和/或高半胱氨酸内源性地产生。H2S生产 减少阿尔茨海默病（AD），老年人痴呆症的最常见原因，和H2S供体 据报道具有有益的效果。然而，这一下降的机械基础仍然没有 被阐明。H2S通过翻译后修饰调节多种生理过程， 作为硫水合，其中反应性半胱氨酸残基的-SH基团转化为过硫化物或-SSH 组我们和其他人之前进行的研究表明，在衰老过程中，这是最大的风险因素， 发展为AD时，大脑中的硫水合作用减少。我们进行的初步研究显示， 微管相关蛋白是AD中神经元缠结的一种成分，与胱硫醚γ-裂解酶结合 (CSE)是H2S的生物合成酶之一，并激活它。 在这项研究中，我们提出了表征的三个生物合成酶的相互作用H2S，CSE， 胱硫醚β-合成酶（CBS）和3-巯基丙酮酸硫转移酶（3-MST），均在体外细胞培养中 以及在小鼠大脑中的体内。我们还试图阐明H2S对Tau活性的影响。在Aim中 1中，我们将研究CSE、CBS和3-MST与野生型Tau及其亚型的结合。在目标2中，我们将评估 Tau的巯基化状态，并绘制Tau上巯基化的半胱氨酸残基。破译 H2S/Tau通路的信号传导功能不仅将鉴定tau的基本生理功能，而且还将鉴定 精确定位节点，用于AD的治疗干预，这也与其他tau蛋白病相关。

PROJECT SUMMARY Hydrogen sulfide (H2S) is a gaseous signaling molecule which has neuroprotective effects. H2S is generated endogenously from cysteine and/or homocysteine via the reverse transsulfuration pathway. H2S production is diminished in Alzheimer's disease (AD), the most common cause of dementia in the elderly, and H2S donors have been reported to confer beneficial effects. However, the mechanistic basis for this decrease has still not been elucidated. H2S regulates several physiological processes via a posttranslational modification designated as sulfhydration, wherein the -SH groups of reactive cysteine residues are converted to persulfide or -SSH groups. Prior studies conducted by us and others show that during aging, which is the biggest risk factor for developing AD, sulfhydration is decreased in the brain. Preliminary studies conducted by us show that Tau, the microtubule associated protein, and a component of neurofibrillary tangles in AD, binds cystathionine γ-lyase (CSE), one of the biosynthetic enzymes for H2S and activates it. In this study we propose to characterize the interaction of the three biosynthetic enzymes for H2S, CSE, cystathionine β-synthase (CBS) and 3-mercaptopyruvate sulfurtransferase (3-MST), both in vitro in cell culture as well as in vivo in the mouse brain. We also seek to elucidate the effects of H2S on the activity of Tau. In Aim 1, we will study the binding of CSE, CBS and 3-MST to wild type Tau and its isoforms. In Aim 2, we will evaluate the sulfhydration status of Tau and map the cysteine residues on tau which are sulfhydrated. Deciphering the signaling functions of the H2S/Tau pathway will not only identify basic physiological functions of tau, but also pinpoint nodes for therapeutic intervention in AD, which are also relevant for other tauopathies.