Kalirin-7's role in synaptic transmission, plasticity and learning and memory

描述（由申请人提供）：本研究项目的总体目标是更好地了解钾素-7在兴奋性突触传递和可塑性中的作用，以及该蛋白功能的破坏如何可能涉及复杂的神经精神疾病，如精神分裂症和阿尔茨海默病。本次K99/R00独立之路奖的申请人Bruce Herring博士是加州大学旧金山分校Roger Nicoll博士的博士后研究员。他的长期职业目标是作为学术研究机构的终身研究员，领导基础神经科学研究的独立研究实验室。他的长期研究目标是使用细胞、分子、电生理、成像、生化和遗传方法的组合来阐明控制突触传递、突触可塑性基础和引起神经精神疾病的细胞和突触水平机制。尽管精神分裂症的病因机制在很大程度上仍不清楚，但药理学、遗传学和形态学数据的融合表明，这种疾病存在脊柱稳定性、兴奋性传递和突触可塑性的失调。Kalirin-7已被证明在脊髓和突触发生和维持中起关键作用，由DISC1（一种与精神分裂症密切相关的蛋白质）调节，KALRN基因的几个突变已被确定为这种疾病的可能遗传风险因素。此外，CaMKII对n端苏氨酸残基（T95）的磷酸化增强了kalilin -7激活参与调节突触形态的小gtp酶的能力。CaMKII对长期增强（LTP）的诱导至关重要，LTP被认为是突触可塑性的主要机制之一，通常被认为是学习和记忆的细胞基础。然而，CaMKII磷酸化引起LTP的靶标尚未确定。考虑到kalirin-7在LTP中的潜在作用，再加上该蛋白在树突脊柱维持和许多神经精神疾病中的意义，可能表明kalirin-7代表了学习、记忆和神经精神疾病的分子机制之间的关键趋同点。利用创新的遗传方法组合，允许内源性kalirin被单个神经元中的重组kalirin-7突变体所取代，Herring博士提出了一个系统的研究CaMKII对kalirin-7磷酸化在兴奋性突触形态、功能、学习和记忆中的作用。通过结合他在分子和细胞生物学、药理学和突触电生理学方面的培训，Herring博士将在成像和生化方法方面进行额外的培训，以解决以下具体目标：1)确定kalirin-7磷酸化在兴奋性突触、学习和记忆的调节中所起的作用；2)确定kalirin-7和Trio是否代表支持LTP的冗余通路；3)识别涉及kalilin -7的功能相关蛋白-蛋白相互作用。这项应用的成功完成将确定LTP的新机制和新蛋白质，并将为精神分裂症和其他神经精神疾病的疾病改善治疗方法的发展开辟新的领域。此外，K99/R00奖所提供的培训期将为贺林博士的独立职业生涯提供强大的工具箱，研究突触传递，可塑性和疾病的分子机制。

DESCRIPTION (provided by applicant): The overall goal of this research program is to better understand the role of kalirin-7 in excitatory synaptic transmission and plasticity and how disruption of the function of this protein might be involved in complex neuropsychiatric disorders such as schizophrenia and Alzheimer's disease. The applicant for this K99/R00 Pathway to Independence Award, Dr. Bruce Herring, is a postdoctoral fellow with Dr. Roger Nicoll at UCSF. Dr. Herring's long-term career goal is to lead an independent research laboratory in basic neuroscience research as a tenure-track principle investigator in an academic research institution. Dr. Herring's long-term research goal is to use a combination of cellular, molecular, electrophysiological, imaging, biochemical and genetic approaches to elucidate the cellular and synaptic level mechanisms that govern synaptic transmission, underlie synaptic plasticity and give rise to neuropsychiatric disease. Though etiological mechanisms underlying schizophrenia remain largely unknown, a convergence of pharmacologic, genetic and morphological data implicates a dysregulation of spine stability, excitatory transmission and synaptic plasticity in tis disease. Kalirin-7 has been shown to have a critical role in spino- and synaptogenesis and maintenance, is regulated by DISC1, a protein heavily implicated in schizophrenia, and several mutations in the KALRN gene have been identified as possible genetic risk factors for this disease. Furthermore, phosphorylation of an N-terminal threonine residue (T95) by CaMKII augments kalirin-7's ability to activate small GTPases that are involved in regulating synapse morphology. CaMKII is critical in the induction of long-term potentiation (LTP), a phenomenon thought to be one of the primary mechanisms underlying synaptic plasticity and generally regarded as the cellular basis of learning and memory. However, the targets of CaMKII phosphorylation responsible for giving rise to LTP have not been identified. Given kalirin-7's potential role in LTP, coupled with the implication of this protein in dendritic spine maintenance and a number of neuropsychiatric diseases, may indicate that kalirin-7 represents a key point of convergence between the molecular mechanisms underlying learning, memory and neuropsychiatric disorders. Using a combination of innovative genetic approaches allowing endogenous kalirin to be replaced with recombinant kalirin-7 mutants in individual neurons, Dr. Herring proposes a systematic investigation into the role of kalirin-7 phosphorylation by CaMKII in excitatory synaptic morphology, function and learning and memory. By combining his training in molecular and cellular biology, pharmacology and synaptic electrophysiology, Dr. Herring will pursue additional training in imaging and biochemical methods to address the following specific aims: 1) Determine the role kalirin-7 phosphorylation plays in the regulation of excitatory synapses, learning and memory; 2) Identify whether kalirin-7 and Trio represent redundant pathways supporting LTP; 3) Identify functionally relevant protein-protein interactions involving kalirin-7. Successful completion of this application will identify new mechanisms and new proteins underlying and modulating LTP and will open new frontiers for the development of disease-modifying therapeutic approaches for schizophrenia and other neuropsychiatric disorders. Furthermore, the training period afforded by the K99/R00 Award will provide Dr. Herring with a powerful toolbox for his independent career investigating the molecular mechanisms underlying synaptic transmission, plasticity and disease.