Novel mechanisms for distal transport in developing and mature neurons

描述(申请人提供)：神经性蜡样脂褐素病(NCLS)是一种毁灭性的神经退行性疾病家族，由多达14个不同基因的突变引起。长期以来，研究人员一直在寻找各种NCL之间的分子联系。最近的研究表明，与该病的膜相关蛋白形式相关的一种常见的NCL途径(CLN3、CLN6、CLN5、CLN8)可能是通过破坏与细胞骨架网络的相互作用而在细胞内运输。为了支持这一概念，我们已经确定了 一种新的复合体，包含ER相关的CLN6，其突变导致变异的婴儿晚期NCL(VLINCL)，崩溃素反应介体蛋白2(CRMP2)和动蛋白马达蛋白KLC4。CRMP2通过蛋白质相互作用的网络作用，调节神经发育过程中轴突/树突状细胞的指定和延伸，并有助于成熟大脑的维持/再生。我们假设CRMP2/CLN6/KLC4(CCK)复合体利用CLN6作为内质网小泡上的“分子标签”，将货物分离到树突和轴突的远端位置。这种信号复合体的破坏可能通过改变神经元突起的生长和维持而参与vLINCL的发病。为了验证这一假说，我们提出了以下目标：1)确定CCK复合体如何调控神经元的内质网-囊泡运输的发育和维持；2)确定CCK复合体转运如何与神经元分化的早期事件有关，并确定哪些货物是由CLN6标记的囊泡转运的；以及3)确定CRMP2相关复合体的稳定是否可以改善临床前NCL小鼠模型的神经功能缺陷。这些研究将扩大我们对CLN6的S在关键细胞过程中的贡献的理解，并开始揭示CCK复合体在发育和成熟神经元中的生物学意义，以及它在神经系统疾病(如NCLS)中的作用和细胞内转运的作用。

DESCRIPTION (provided by applicant): The neuronal ceroid lipofuscinoses (NCLs) are a family of devastating neurodegenerative diseases resulting from mutations in as many as 14 different genes. Researchers have long sought a molecular link between various NCLs. Recent studies suggest a common NCL pathway associated specifically with membrane associated protein forms of the disease (CLN3, CLN6, CLN5, CLN8) may be intracellular transport via disrupted interaction with the cytoskeletal network. In support of this concept, we have identified a novel complex containing the ER-associated CLN6, whose mutation results in a variant late infantile NCL (vLINCL), the collapsin response mediator protein 2 (CRMP2), and the kinesin motor protein, KLC4. Acting through a network of protein interactions, CRMP2 regulates axonal/dendritic specification and extension during neurodevelopment and contributes to maintenance/regeneration in the mature brain. We hypothesize that the CRMP2/CLN6/KLC4 (CCK) complex utilizes CLN6 as a "molecular tag" on ER-vesicles for segregation of cargo to distal sites in dendrites and axons. Disruption of this signaling complex could contribute to the pathogenesis of vLINCL through altered neuronal process outgrowth and maintenance. To test this hypothesis, we propose aims that will 1) determine how the CCK complex regulates ER-vesicle transport development and maintenance of neurons; 2) define how CCK complex transport is linked to early events in neuronal differentiation and identify what cargo is transported by CLN6-tagged vesicles; and 3) determine if stabilization of CRMP2-associated complexes, independent of CLN6 rescue, could ameliorate neurological deficits in a pre- clinical NCL mouse model. These studies will expands our understanding of CLN6's contribution to crucial cellular processes and start to unravel the biological significance of the CCK complex in developing and mature neurons, as well as its role and the role of intracellular trafficking in neurological disorders such as the NCLs.