Structural and Molecular Mechanisms for Dysregulation of Protein Kinase C Gamma in Cerebellar Ataxia

摘要/摘要 我们提出的研究的总体愿景是了解结构，分子和细胞 蛋白激酶C γ（PKC g）的生殖系突变驱动神经细胞凋亡的机制。 脊髓小脑性共济失调14（SCA 14）。PKCg是一种钙/二酰基甘油调节的激酶 仅在神经元中表达，包括浦肯野细胞，其变性是近50个神经元的标志。 SCA的子类型。我们组建了一个在结构方面具有广泛和互补专业知识的团队， 激酶和PKC机制的生物学，以了解这些突变如何改变结构， PKCg的功能有助于疾病表型。推动这一提议的假设是， 突变集中在PKCg的特定区域，这些区域破坏自身抑制接触，以增强其 活性通过一种新的机制，避免正常的质量控制退化。这种逃避 降解可能是共济失调突变的一个独特特征，因为癌症相关的突变， 自身抑制接触使PKC不稳定并使其转向降解。这种逃避正常质量 控制允许异常活性的PKC g增强其信号输出，这在浦肯野细胞中是一个非常重要的过程。 小脑导致退化此外，我们假设PKC g增强的信号传导可能 一般来说，SCA的病理基础，因为大部分SCA是由蛋白质突变引起的 控制Ca 2+稳态或信号传导。我们的目标是联合收割机， 活细胞成像和磷酸化蛋白质组学方法，以了解分子的细节， 疾病相关的PKCg突变影响功能，未来的长期目标是使用这种方法。 治疗这种毁灭性疾病的知识

Summary/Abstract The overall vision of our proposed research is to understand the structural, molecular, and cellular mechanisms by which germline mutations in protein kinase C gamma (PKCg) drive the neuro- degenerative disease Spinocerebellar Ataxia 14 (SCA14). PKCg is a Ca2+/diacylglycerol-regulated kinase expressed only in neurons, including Purkinje cells whose degeneration is a hallmark of the almost 50 subtypes of SCA. We have assembled a team with extensive and complementary expertise in structural biology of kinases and in PKC mechanisms to understand how these mutations alter the structure and function of PKCg to contribute to the disease phenotype. The hypothesis driving this proposal is that mutations are concentrated at specific regions of PKCg that break autoinhibitory contacts to enhance its activity by a novel mechanism that evades normal quality control degradation. This evasion of degradation may be a unique feature of the Ataxia mutations as cancer-associated mutations that break autoinhibitory contacts destabilize PKC and shunt it to degradation. Such evasion of normal quality control allows aberrantly active PKCg to enhance its signaling output, which in Purkinje cells in the cerebellum leads to degeneration. Furthermore, we hypothesize that enhanced signaling by PKCg may underlie the pathology of SCA, in general, as a large fraction of SCAs are caused by mutations in proteins that control Ca2+ homeostasis or signaling. We aim to combine computational, structural, biochemical, live-cell imaging, and phosphoproteomics approaches to understand the molecular details of how disease-associated mutations in PKCg impact function, with the long-term future goal of using this knowledge to treat this devastating disease.