Force-dependent detachment of kinesin-2 biases track switching at cytoskeletal filament intersections |
| |
Authors: | Harry W Schroeder Adam G Hendricks Kazuho Ikeda Henry Shuman Vladimir Rodionov Mitsuo Ikebe Yale E Goldman Erika L F Holzbaur |
| |
Affiliation: | Pennsylvania Muscle Institute and Department of Physiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA. |
| |
Abstract: | Intracellular trafficking of organelles often involves cytoskeletal track switching. Organelles such as melanosomes are transported by multiple motors including kinesin-2, dynein, and myosin-V, which drive switching between microtubules and actin filaments during dispersion and aggregation. Here, we used optical trapping to determine the unitary and ensemble forces of kinesin-2, and to reconstitute cargo switching at cytoskeletal intersections in a minimal system with kinesin-2 and myosin-V motors bound to beads. Single kinesin-2 motors exerted forces up to ~5 pN, similar to kinesin-1. However, kinesin-2 motors were more likely to detach at submaximal forces, and the duration of force maintenance was short as compared to kinesin-1. In multimotor assays, force increased with kinesin-2 density but was not affected by the presence of myosin-V. In crossed filament assays, switching frequencies of motor-bound beads were dependent on the starting track. At equal average forces, beads tended to switch from microtubules onto overlying actin filaments consistent with the relatively faster detachment of kinesin-2 at near-maximal forces. Thus, in addition to relative force, switching probability at filament intersections is determined by the dynamics of motor-filament interaction, such as the quick detachment of kinesin-2 under load. This may enable fine-tuning of filament switching in the cell. |
| |
Keywords: | |
本文献已被 ScienceDirect PubMed 等数据库收录! |
|