Influence of cargo geometry on axonal transport kinetics

描述(由申请人提供)：神经肌肉系统的正常功能需要通过分子马达介导的运输，将各种货物从神经元细胞体沿着轴突长度输送到目的地。鉴于货物的多样性，关于货物大小、发动机密度和轴突几何形状等关键变量如何相互作用影响货物-发动机复合体运输的信息令人惊讶地缺乏。拟议的实验将检验关于货物大小和货物速度、货物运行长度和货物运动连续性之间的关系的假设。此外，还将测试有关物理阻塞对轴突运输的影响的假设，例如在几种神经退行性疾病的病理学中发现的那些。为了验证这些假设，我建议1)通过成像不同直径的荧光珠在培养神经元中的运动来量化货物大小对运输动力学的影响，2)通过成像特定大小的工程小泡的运输来确定货物大小对运输动力学的影响，以及3)通过将聚集的β-淀粉样纤维引入培养的神经元来表征蛋白质积累对运输的影响。

DESCRIPTION (provided by applicant): Proper function of the neuro-muscular system requires the delivery of a variety of cargoes from the neuronal cell body to destinations along the length of the axon via molecular motor-mediated transport. Given the diversity of cargoes, there is a surprising lack of information on how critical variables such as cargo size, motor density, and axonal geometry interact to affect the transport of cargo-motor complexes. The proposed experiments will test hypotheses regarding relationships between cargo size and cargo velocity, cargo run lengths, and the continuity of cargo motion. In addition, hypotheses regarding the effects of physical blockages, such as those found in the pathology of several neurodegenerative diseases, on axonal transport will be tested. Towards the testing of these hypotheses, I propose to 1) quantify the influence of cargo size on transport kinetics by imaging the motion of fluorescent beads of different diameters in cultured neurons, 2) to determine the influence of cargo size on transport kinetics by imaging the transport of vesicles engineered to specified sizes, and 3) To characterize the effects of protein accumulation on transport by introducing aggregated beta-amyloid fibrils into cultured neurons.