Role of Autism Susceptibility Gene, TAOK2 kinase, and its novel substrates in Synaptogenesis

 描述（由申请人提供）：树突棘是专门的富含肌动蛋白的突起，作为大脑中大多数兴奋性突触的主要接受者。脊柱是非常动态的，在发育过程中表现出不同的结构和功能变化，以响应刺激，以及学习和记忆。虽然有大量的证据表明，几种神经发育和精神疾病汇聚在一个共同的主题异常脊柱形成，脊柱形成的机制和它的功能障碍如何与疾病还不清楚。TAOK 2是一种参与神经元发育的丝氨酸/苏氨酸激酶，是16p11.2基因座中存在的基因之一。该区域的缺失是与自闭症谱系障碍（ASD）相关的最常见的风险因素。尽管TAOK 2激酶与神经元发育和ASD相关，但其生理神经元底物尚不清楚。目前尚不清楚TAOK 2信号传导如何介导脊柱发育，以及TAOK 2基因剂量的不平衡如何导致与ASD相关的神经元和行为改变。使用创新方法的组合，该提案旨在描述TAOK 2激酶在突触发生过程中的机制作用，并了解该信号通路中的功能障碍如何导致疾病。作为博士的博士后研究员Yuh-Nung Jan在UCSF的实验室，我获得了神经生物学，质谱和化学遗传学的技能，除了我的细胞生物学和生物化学的研究生背景。对于本申请中提出的实验，我寻求干细胞技术，超分辨率显微镜和定量蛋白质组学的跨学科指导培训。我组建了一个导师团队，他们在以下领域拥有专业知识：质谱和蛋白质组规模的数据采集和分析（Al Burlingame博士），iPSC技术（Kathryn Ivey和Lauren韦斯博士），神经发育和ASD（John Rubenstein博士），以及超分辨率显微镜（Bo Huang博士）。这次培训将使我能够实现以下目标：1）使用超分辨率STORM成像系统研究脊柱发育期间的TAOK 2定位，2）使用化学遗传学方法鉴定和表征TAOK 2激酶的直接新靶点，3）使用来自16p11.2缺失患者的iPSC衍生神经元表征ASD病理中的TAOK 2通路。通过K99阶段获得的新培训和信息，我将扩大R 00阶段的研究范围。我将分析TAOK 2磷酸化靶点在神经元发育过程中的作用。我还将对16p11.2缺失iPSC衍生的神经元进行磷酸化蛋白质组学分析，以确定TAOK 2剂量不平衡引起的全局变化，这可能揭示ASD发病机制的临床相关见解。K99/R 00奖提供的培训期将极大地促进我作为独立研究者的长期目标，以阐明正常和疾病状态下树突棘形成所涉及的信号通路。

 DESCRIPTION (provided by applicant): Dendritic spines are specialized actin-rich protrusions that serve as primary recipients of most excitatory synapses in the brain. Spines are extremely dynamic, exhibiting diverse structural and functional changes during development, in response to stimuli, as well as in learning and memory. While there is substantial evidence that several neurodevelopmental and psychiatric diseases converge on a common theme of aberrant spine formation, the mechanisms of spine formation and how its dysfunction relates to disease is unclear. TAOK2 is a serine/threonine kinase implicated in neuronal development, and is one of the genes present in the 16p11.2 genomic locus. Deletion of this region is the most common risk factor associated with autism spectrum disorder (ASD). Despite its relevance in neuronal development and to ASD, the physiological neuronal substrates of TAOK2 kinase are not known. It is unclear how TAOK2 signaling mediates spine development and how an imbalance in TAOK2 gene dosage might contribute to neuronal and behavioral alterations associated with ASD. Using a combination of innovative approaches, this proposal aims to delineate the mechanistic role of TAOK2 kinase during synaptogenesis and to understand how dysfunction in this signaling pathway might contribute to disease. As a postdoctoral fellow in Dr. Yuh-Nung Jan's laboratory at UCSF, I have gained skills in neurobiology, mass spectrometry, and chemical-genetics in addition to my graduate background in cell biology and biochemistry. For the experiments proposed in this application, I seek interdisciplinary mentored training in stem cell technology, super-resolution microscopy, and quantitative proteomics. I have assembled a team of mentors with expertise in: mass spectrometry and proteome-scale data acquisition and analysis (Dr. Al Burlingame), iPSC technology (Drs. Kathryn Ivey and Lauren Weiss), neurodevelopment and ASD (Dr. John Rubenstein), and super-resolution microscopy (Dr. Bo Huang). This training will allow me to achieve the following aims: 1) systematic investigation of TAOK2 localization during spine development using super-resolution STORM imaging, 2) identification and characterization of direct novel targets of TAOK2 kinase using a chemical-genetic approach, and 3) characterization of the TAOK2 pathway in ASD pathology using iPSC derived neurons from 16p11.2 deletion patients. With the new training and information acquired in the K99 phase, I will extend the scope of my research in the R00 phase. I will analyze the role of the identified TAOK2 phosphorylation targets during neuronal development. I will also perform phosphoproteomic analysis of 16p11.2 deletion iPSC-derived neurons to identify global changes caused by imbalances in TAOK2 dosage, which may reveal clinically relevant insights into the pathogenesis of ASD. The training period afforded by the K99/R00 award will greatly facilitate my long-term goal as an independent investigator to elucidate signaling pathways involved in dendritic spine formation during normal and disease states.