Step by step: Engineering kinesins to study cargo trafficking in neurons

The brain consists of billions of brain cells, also called neurons, which form a complex network. To ensure proper signal transduction from cell to cell, it is of great importance that each neuron has the right building blocks at the right moment at the right place. This transport is mediated by so called motor proteins. The research in this thesis focusses on a family of motor proteins, the kinesins. There are more than 40 different kinesins in neurons and there are even more different types of building blocks. Therefore, each neuron has a complex transport network, in which each kinesin knows exactly what to transport where. This thesis describes the development of a new method that can be used to study kinesins. This method is combined with other biochemical techniques to study the regulation of the kinesin KIF1A. First, the interaction of KIF1A with the inhibiting protein KBP is elucidated, which regulates the activity of the motor. Next, different building blocks of KIF1A are identified and it is shown that specificity for each building block is regulated by different adaptor proteins. Furthermore, it is shown that KIF1A interacts with KIF5 in the transport of the TrkB receptor. These insights into the regulation of KIF1A contribute to our fundamental knowledge about the transport mechanisms in neurons. This is an important step in understanding the neuronal transport network and ultimately to solve brain diseases caused by disruptions in this network.