Spatial Relationships Matter: Kinesin-1 Molecular Motors Transport Liposome Cargo Through 3D Microtubule Intersections

Kinesin-1 ensembles maneuver vesicular cargoes through intersections in the 3-dimensional (3D) intracellular microtubule (MT) network. To characterize directional outcomes (straight, turn, terminate) at MT intersections, we challenge 350 nm fluid-like liposomes transported by ∼10 constitutively active, truncated kinesin-1 KIF5B (K543) with perpendicular 2-dimensional (2D) and 3D intersections Kinesin-1 molecular motors transport vesicles containing essential cellular resources along the dense 3D microtubule (MT) cytoskeleton, with dysfunctions linked to neurodegenerative diseases such as Alzheimer's. Despite its importance, the mechanism by which kinesin-1s maneuver intracellular cargoes through MT-MT intersections towards their destination remains unclear. Therefore, we developed a 3D