Title: The Kinesin-1 Tail Binds to Microtubules in a Manner Similar to Tau
Abstract: The kinesin-1 molecular motor contains two microtubule binding sites: an ATP-dependent site in the head domain and an ATP-independent site in the tail domain. In this work we show that the tail binds to microtubules with a sub-micromolar affinity, and that binding is mediated largely by electrostatic interactions. The tail binds to a site on microtubules that is distinct from the head domain binding-site but overlaps with the binding-site of the microtubule associated protein (MAP) tau. Tail binding also stimulates the assembly and promotes the stability of microtubule filaments in a manner similar but not identical to tau. The tail's microtubule binding-site is in close proximity to its regulatory and cargo-binding regions, which suggests that the tail-microtubule interaction described in this work may prove to play an important role in the activity and regulation of the kinesin-1 motor in the cell.