KIF14 Binds Tightly to Microtubules and Adopts a Rigor-Like Conformation

Abstract

The mitotic kinesin motor protein KIF14 is essential for cytokinesis during cell division and has been implicated in cerebral development and a variety of human cancers. Here we show that the mouse KIF14 motor domain binds tightly to microtubules and does not display typical nucleotide-dependent changes in this affinity. It also has robust ATPase activity but very slow motility. A crystal structure of the ADP-bound form of the KIF14 motor domain reveals a dramatically opened ATP-binding pocket, as if ready to exchange its bound ADP for Mg·ATP. In this state, the central β-sheet is twisted ~10° beyond the maximal amount observed in other kinesins. This configuration has only been seen in the nucleotide-free states of myosins-known as the "rigor-like" state. Fitting of this atomic model to electron density maps from cryo-electron microscopy indicates a distinct binding configuration of the motor domain to microtubules. We postulate that these properties of KIF14 are well suited for stabilizing midbody microtubules during cytokinesis.

The structure of apo-kinesin bound to tubulin links the nucleotide cycle to movement

“…Remarkably, in the recently determined rigorlike structure of the kinesin-3 KIF14 (ref. 21), the residue equivalent to Ile9 (a valine) is located as in the nucleotide-free complex and would interfere with neck-linker docking similarly to Ile9 in kinesin (Fig. 2d).…”

“…The structural similarity of the kinesin motor domain core to the myosin catalytic domain surrounding the nucleotide was noticed when the first kinesin structure was determined 5 and suggested a common evolutionary ancestor 27 . However, whereas a substantial rearrangement of the core b sheet has been seen in nucleotide-free myosins [28][29][30] , such a change has long been looked for unsuccessfully in kinesins 31 and the resulting distortion was observed only recently in the KIF14-ADP structure 21 . Our data demonstrate that the core b sheets in nucleotide-free and kinesin-ATP are distorted in respect to each other ( Supplementary Fig.…”

Inhibition of KIF14 Suppresses Tumor Cell Growth and Promotes Apoptosis in Human Glioblastoma

“…KIF14 was initially cloned in 1994 and since then shown to be an important molecular motor characterized by a C-terminal citron kinase binding domain and an N-terminal motor domain that shows a distinct mechanism of binding to microtubules [24,25]. KIF14 has been referred to as an oncogenic kinesin because it is overexpressed in many cancers and is correlated with poor prognosis [26][27][28].…”

Kif14: A Clinically Relevant Kinesin and Potential Target for Cancer Therapy

“…The biochemistry and crystal structure of the murine Kif14 motor domain reveal some unique features [ 10 ]. These include sequence divergence in loops L8a, L10, L11, and L12 compared to other N-3 kinesins, and a small difference in orientation of Kif14 on the microtubule, as observed by cryo-electron microscopy.…”