Neuronal Ykt6 Protein Interactions and Targeting

描述（由申请人提供）： SNAP受体（SNARE）蛋白催化生物膜融合，并有助于细胞内膜运输的保真度-它们可能是细胞器在细胞中运输的最基本决定因素。酵母异戊二烯化SNARE ykt 6p似乎在组成性分泌途径中具有多种功能。出乎意料的是，我们的结果表明，哺乳动物ykt 6不具有组成性分泌的SNARE特征，因为它主要在神经元中表达。此外，膜结合大鼠ykt 6定位于独特的细胞质囊泡结构，不明显重叠与公认的细胞器的分泌或内体系统。这项提议旨在极大地推进我们对神经元ykt 6及其参与的专门转运过程的理解。我们的指导性假设是，大鼠ykt 6参与了一个高度专业化的运输细胞器，包含货物，是重要的神经元功能方面的贩运。具体目标是：1.检验ykt 6与神经元SNARE和其他膜和胞质蛋白的独特子集相互作用的假设。2.检验ykt 6定位于一个专门的运输室的假设，该运输室含有与神经元功能相关的货物。3.测试NT结构域通过结合特定的膜受体将ykt 6靶向其特定位置的假设。4.检验胞质ykt 6 SNARE相互作用通过NT结构域和异戊烯基之间的合作而自动抑制的假设。这些研究将极大地推进我们对神经元膜运输的理解，并突出可能导致人类疾病的潜在过程。在这项工作中发现的许多SNARE监管原则将适用于SNARE功能在多个膜运输步骤。重要的是，ykt 6是一种异戊烯基蛋白，预计可被蛋白法尼基转移酶修饰。目前很少有关于法尼基化蛋白质不参与细胞增殖的功能的信息。由于许多最有前途的新癌症治疗方法使用药物来抑制蛋白质法尼基转移酶，因此必须了解蛋白质法尼基化停止时受影响的主要代谢途径。为了理解和潜在地补偿这些药物在神经元中的意外后果，理解ykt 6膜转运途径的功能是至关重要的。

DESCRIPTION (provided by applicant): SNAP receptor (SNARE) proteins catalyze biological membrane fusion and contribute to the fidelity of intracellular membrane traffic - they are perhaps the most fundamental determinant of an organelle's trafficking in the cell. The yeast prenylated SNARE ykt6p appears to have multiple functions in the constitutive secretory pathway. Unexpectedly, our results demonstrate that mammalian ykt6 does not have the characteristics of a SNARE for constitutive secretion, as it is expressed predominantly in neurons. Furthermore, membrane bound rat ykt6 localizes to unique cytoplasmic vesicular structures that do not overlap appreciably with recognized organelles of the secretory or endosomal systems. This proposal aims to dramatically advance our understanding of neuronal ykt6 and the specialized transport process(es) in which it participates. Our guiding hypothesis is that rat ykt6 is involved in the trafficking of a highly specialized transport organelle containing cargo that is important for aspects of neuronal function. The specific aims are: 1. Test the hypothesis that ykt6 interacts with a unique subset of neuronal SNAREs and other membrane and cytosolic proteins. 2. Test the hypothesis that ykt6 is localized to a specialized transport compartment containing cargo relevant to neuronal function. 3. Test the hypothesis that the NT domain targets ykt6 to its specialized location by binding to a specific membrane receptor. 4. Test the hypothesis that cytosolic ykt6 SNARE interactions are autoinhibited by cooperation between the NT domain and prenyl group(s). These studies will dramatically advance our understanding of membrane trafficking in neurons, and highlight underlying processes that may contribute to human disease. Many of the SNARE regulatory principles discovered in this work will be applicable to SNARE function at multiple membrane transport steps. Importantly, ykt6 is a prenyl protein that is predicted to be modified by protein farnesyltransferase. There is currently little information about the function of farnesylated proteins not involved in cell proliferation. Since many of the most promising new cancer treatments use drugs to inhibit protein farnesyltransferase, it is essential to understand the major metabolic pathways affected when protein farnesylation is stopped. To understand and potentially compensate for the unintended consequences of these drugs in neurons, it is essential to understand the function of the ykt6 membrane transport pathway.