Regulation and Neural Function of Atypical PKC

非典型PKC的调节和神经功能

• 批准号: 8245390
• 负责人: TODD C SACKTOR
• 金额: $ 39.88万
• 依托单位: SUNY DOWNSTATE MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-04-01 至 2016-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8245390
• 关键词: 1,2-diacylglycerol; AMPA Receptors; Affect; Behavior; Behavioral; Binding; Binding Sites; Brain; C-terminal; Catalytic Domain; Chemosensitization; Cyclic AMP-Dependent Protein Kinases; Data; Dendrites; Diglycerides; Disease; Dominant-Negative Mutation; Endocytosis; Exocytosis; Funding; Genes; Genetic; Genetic Transcription; GluR2 subunit AMPA receptor; Goals; Grant; Hippocampus (Brain); Hour; Information Storage; Knowledge; Laboratories; Lead; Length; Long-Term Potentiation; MAP Kinase Gene; Maintenance; Mediating; Memory; Memory Disorders; Messenger RNA; Modification; Molecular; N-terminal; Neurobiology; Neurology; Neurons; Neurophysiology - biologic function; Pathway interactions; Perfusion; Phase; Phosphotransferases; Protein Isoforms; Protein Kinase; Protein Kinase C; Proteins; Psychiatry; Pyramidal Cells; Regulation; Rodent; Role; Second Messenger Systems; Signaling Molecule; Site; Synapses; Synaptic Transmission; Synaptic plasticity; Testing; Time; Training; Translating; Translations; Work; atypical protein kinase C; calmodulin-dependent protein kinase II; inhibitor/antagonist; long term memory; overexpression; postsynaptic; prevent; promoter; protein transport; receptor; receptor function; second messenger; trafficking

DESCRIPTION (provided by applicant): Long-term memories are believed to be due to persistent changes in synaptic strength. Although the molecular mechanisms initiating these changes have been extensively studied, the mechanisms maintaining these changes, which may contribute to storing long-term memory, have been unknown. Recently, however, a candidate molecular mechanism has emerged for maintaining a persistent form of synaptic enhancement triggered by strong afferent stimulation of synapses, known as long-term potentiation (LTP). The key molecule in this maintenance mechanism is a brain-specific, protein kinase C isoform, PKM6. Unlike other PKC isoforms that require second messengers for activation, PKM6 consists of an independent PKC catalytic domain that is constitutively active. PKM6 is produced from a PKM6 mRNA, and the amount of the kinase increases with LTP induction. The persistent activity of the kinase is then both necessary and sufficient for maintaining the synaptic enhancement. Postsynaptic perfusion of PKM6 enhances synaptic transmission, and inhibition of PKM6 activity reverses previously established LTP. Recently, PKM6 inhibition has been found to disrupt the storage of previously established long-term memories. These data indicate that PKM6 is a candidate molecule uniquely important for information storage at synapses and during behavior. Thus the overall goal of this application is to elucidate in mechanistic detail the function of PKM6 in persistent synaptic enhancement and memory storage. Our 3 Specific Aims are: 1) To characterize the mechanisms by which PKM6 enhances synaptic strength. We found that PKM6 potentiates synaptic strength by increasing the number of postsynaptic AMPA receptors (AMPARs) through interactions between the AMPAR GluR2 subunit and the trafficking protein NSF. We will examine whether this potentiation is through increased exocytosis and/or decreased endocytosis of postsynaptic AMPARs and the function of this altered trafficking in memory maintained by PKM6. 2) To determine whether preexisting and newly translated PKM6 mediate distinct phases of potentiation during LTP. Preliminary evidence indicates that antisense oligodeoxynucleotides blocking new PKM6 synthesis prevents the persistence of a phase of LTP. We will determine whether this new synthesis occurs at dendritic sites. 3) To determine the role of preexisting, newly translated, and new gene transcription of PKM6 in distinct phase of memory. PKM6 maintains memory up to several months after training. We will employ both antisense to block translation of PKM6 mRNA and conditional genetic deletion of PKM6 to examine the function of distinct mechanisms of expression of PKM6 in different phases of memory. These 3 aims will provide fundamental new information on a potential molecular mechanism for maintaining synaptic and behavioral information storage, which may be relevant to both normal memory and its disorders. PUBLIC HEALTH RELEVANCE: How long-term memories are stored in the brain is a fundamental neurobiological question, with many implications for neurology and psychiatry, but the molecular mechanisms of memory maintenance have been unknown. Recently, however, the persistent action of a protein kinase, termed PKM6, has been found to be one potential mechanism for maintaining memory. This application is to characterize the functional mechanisms by which PKM6 maintains long-term information at synapses and during behavioral memory storage.

描述（由申请人提供）：长期记忆被认为是由于突触强度的持续变化所致。尽管引发这些变化的分子机制已被广泛研究，但维持这些变化的机制（可能有助于存储长期记忆）尚不清楚。然而，最近出现了一种候选分子机制，用于维持突触强传入刺激所触发的持久形式的突触增强，称为长时程增强（LTP）。这种维持机制中的关键分子是大脑特异性的蛋白激酶 C 亚型 PKM6。与其他需要第二信使才能激活的 PKC 亚型不同，PKM6 由一个具有组成型活性的独立 PKC 催化结构域组成。 PKM6 由 PKM6 mRNA 产生，并且激酶的量随着 LTP 的诱导而增加。激酶的持续活性对于维持突触增强来说既是必要的也是充分的。 PKM6 的突触后灌注可增强突触传递，抑制 PKM6 活性可逆转先前建立的 LTP。最近，发现 PKM6 抑制会破坏先前建立的长期记忆的存储。这些数据表明 PKM6 是一种对于突触和行为过程中的信息存储特别重要的候选分子。 因此，本申请的总体目标是详细阐明 PKM6 在持久突触增强和记忆存储中的功能。我们的 3 个具体目标是： 1) 描述 PKM6 增强突触强度的机制。我们发现 PKM6 通过 AMPAR GluR2 亚基和运输蛋白 NSF 之间的相互作用增加突触后 AMPA 受体 (AMPAR) 的数量，从而增强突触强度。我们将检查这种增强是否是通过突触后 AMPAR 的胞吐作用增加和/或内吞作用减少以及 PKM6 维持的记忆运输改变的功能实现的。 2) 确定预先存在的和新翻译的 PKM6 是否介导 LTP 期间不同的增强阶段。初步证据表明，反义寡脱氧核苷酸阻断新的 PKM6 合成可防止 LTP 阶段的持续存在。我们将确定这种新的合成是否发生在树突位点。 3) 确定 PKM6 先前存在的、新翻译的和新的基因转录在不同记忆阶段中的作用。 PKM6 在训练后可保持记忆长达几个月。我们将采用反义来阻断 PKM6 mRNA 的翻译和 PKM6 的条件性基因删除，以检查 PKM6 在不同记忆阶段的不同表达机制的功能。这三个目标将为维持突触和行为信息存储的潜在分子机制提供基本的新信息，这可能与正常记忆及其疾病相关。 公共健康相关性：长期记忆如何存储在大脑中是一个基本的神经生物学问题，对神经学和精神病学有许多影响，但记忆维持的分子机制尚不清楚。然而，最近发现一种名为 PKM6 的蛋白激酶的持续作用是维持记忆的一种潜在机制。该应用旨在表征 PKM6 在突触和行为记忆存储期间维持长期信息的功能机制。