Photo-control of the mitotic kinesin Eg5 using a novel photochromic inhibitor composed of a spiropyran derivative

Abstract

In this study, we synthesized a novel photochromic inhibitor of the mitotic kinesin Eg5, which is composed of the photochromic compound spiropyran to photo-control the function of Eg5. The compound (S)-2, 3-dispiropyran propionic acid (DSPPA) exhibits reversible spiropyran-merocyanine photo-isomerization upon irradiation with visible or ultra-violet light. DSPPA induced reversible changes in the inhibitory effect on Eg5 ATPase and motor activities, which correlates with the spiropyran-merocyanine photo-isomerization. Microtubule-dependent ATPase activity was significantly more inhibited by the spiropyran isomer of DSPPA than by the merocyanine isomer. Additionally, an in vitro motility assay revealed that the microtubule gliding velocity was reduced more by the spiropyran isomer than by the merocyanine isomer. This indicates that the spiropyran derivative may be useful in regulating the function of the mitotic kinesin.

Mechanisms by Which Kinesin-5 Motors Perform Their Multiple Intracellular Functions

“…Since kinesin-5 motors carry their catalytic domain at the N-terminus, they were initially thought to be exclusively plus-end-directed. Indeed, in multi-motor MT gliding assays, where in vitro-polymerized MTs are translocated by surface-bound motors, monomeric and dimeric human, mouse, and Xenopus laevis kinesin-5 variants were shown to move MTs with the minus-ends leading, consistent with a plus-end directionality of the motors [81,[124][125][126]. In contrast to kinesin-1, the velocity of MT gliding driven by kinesin-5 motors was similar for monomers and dimers, suggesting that in order to translocate MTs, coordination between the two motor domains within a dimer is not essential, such that single motor domains can mediate motility so long as the MT is maintained near the surface via the binding of neighboring motors [124,126].…”

The Kinesin Superfamily Handbook

“…Since the motor domain is located at the N-terminus, Kinesin-5s were initially thought to be exclusively plus-end-directed. In multi-motor microtubule gliding assays, monomeric and dimeric human, mouse and X. laevis Kinesin-5s were shown to move microtubules with the minus-ends leading, consistent with a plus-end directionality (Duselder et al, 2012;Kaseda et al, 2008;Sadakane et al, 2018;Yajima et al, 2008). The velocity of microtubule gliding was similar for monomers and dimers, suggesting that to translocate microtubules, coordination between the two motor domains within a dimer is not essential (Kaseda et al, 2008;Yajima et al, 2008).…”