Transport of track-interacted cargo by molecular motor

Abstract Intracellular transports of cargoes are performed by biological molecular motors that move processively along their linear tracks. In some cases, the cargo can interact with the track. A typical example of these cases is the transport of a major mitotic signaling module, the chromosomal passenger complex (CPC), along the microtubule toward the equatorial cortex by a kinesin-6 motor during anaphase, where the CPC can interact with the microtubule. Here, an analytical theory is presented on the dynamics of the molecular motor transporting a track-interacted cargo. The theory is then applied to the transport of the track-interacted cargo by kinesin-6 and by kinesin-1 motors, with the theoretical results reproducing quantitatively the available experimental data. It is found that a diffusive cargo along the track, with the diffusion constant <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mo>≥</mml:mo> </mml:math> 0.1 μm 2 s −1 , can largely enhance the processivity relative to the non-diffusive cargo and relative to the cargo having no interaction with the track.