CellularLogistics · Cellular Logistics: Form, Formation and Function of the Neuronal Microtubule Cytoskeleton

The organization and dynamics of the MT (MT) cytoskeleton underlies the morphology, polarization and division of most cells. The structural polarity of MT determines the directionality of motor proteins, which move selectively towards either the MT plus (most kinesins) or minus end (dynein) to control the transport and positioning of proteins and organelles. Understanding how different cellular MT arrays, such as the mitotic spindle or neuronal MT networks, are built and utilized to ensure proper cellular logistics is a central challenge in cell biology. Recently, our lab has introduced a new technique, motor-PAINT, to directly resolve MT polarity and the relation between MT orientations, stability and modifications. This revealed that in neurons, the mixed polarity MT network in the dendrites is much more ordered than previously anticipated. MTs with opposite orientations have different properties and are preferred by distinct kinesins, revealing an architectural principle that could explain why different plus-end directed motors move towards distinct destinations. Nevertheless, the mechanisms by which this specialized organization is established and the different ways in which it modulates intracellular transport have remained unknown.To resolve how cytoskeletal organization guides transport, I propose to explore the form, formation and functioning of the neuronal MT cytoskeleton. We will combine advanced microscopy, molecular biology, and mathematical modelling to: 1) Create a complete 3D map of the dendritic MT cytoskeleton – form. 2) Unravel the mechanisms that establish MT organization in dendrites – formation. 3) Explore how specific MT configurations modulate intracellular transport – function.This research will uncover key mechanisms of cytoskeletal organization and transport in neurons. In addition, our techniques and concepts will aid understanding intracellular transport in other cellular systems.