Intracellular Cargo Transport by Single-Headed Kinesin Monomers

Kinesins are motor proteins that transport cargoes along microtubules in eukaryotic cells. The canonical picture of kinesin motility is that the two motor domains of a dimer step hand-over-hand in a tightly coordinated manner. However, it remains controversial whether kinesin-3 family motors function as monomers or dimers. We compared truncated, single-headed monomeric motors to their dimeric forms using cargo transport assays in cells. We show that surprisingly, teams of monomeric motors across different kinesin families are able to transport cargoes against high load. Strikingly, monomeric transport capability varies widely even within a single kinesin family. Future work will investigate the structural and mechanical features that enable select monomeric motors to cooperatively transport cargoes. These findings will provide insight into the minimal requirements for collective kinesin motility and intracellular cargo transport.