Kinesin-13 differs from other kinesins because it:
Kinesin superfamily generally couples ATP hydrolysis to processive stepping for cargo transport using hand over hand mechanism but kinesin-13 family including mitotic centromere associated kinesin MCAK KIF2C and KIF2A exhibits depolymerase activity instead of transport. These kinesins possess central motor domain flanked by N and C termini diffuse along microtubule lattice without directional ATP dependent stepping and concentrate at ends via one dimensional diffusion to both tips. At tip they stabilize curved protofilament conformation accelerating removal of tubulin subunits and inducing catastrophe by bending protofilaments outward. Hydrolysis not used for walking but for detaching tubulin and recycling itself after removal. Functionally they regulate spindle length correct erroneous kinetochore attachments by depolymerizing misattached microtubules and tune dynamic instability threshold. Thus kinesin-13 enhances microtubule depolymerization rather than forming filaments or crosslinking actin defining distinct mechanistic class within kinesins important for mitotic fidelity. Additional regulatory inputs including phosphorylation, small GTPases, and cargo adaptors fine tune filament assembly stability and motor activity matching cellular demands during division, migration, and mechanical stress responses efficiently.
Ref: Walczak et al., Annu Rev Cell Dev Biol – Kinesin-13 depolymerase activity mechanism classification.