Cellular cargos, including lipid droplets and mitochondria, are transported along microtubules using molecular motors such as kinesins. Many experimental and computational studies focused on cargos with rigidly attached motors, in contrast to many biological cargos that have lipid surfaces that may allow surface mobility of motors. We extend a mechanochemical 3D computational model by adding coupled-viscosity effects to compare different motor arrangements and mobilities. We show that organizational changes can optimize for different objectives: Cargos with clustered motors are transported efficiently, but are slow to bind to microtubules, whereas those with motors dispersed rigidly on their surface bind microtubules quickly, but are transported inefficiently. Finally, cargos with freely-diffusing motors have both fast binding and efficient transport, although less efficient than clustered motors. These results suggest that experimentally observed changes in motor organization may be a control point for transport.

细胞货物，包括脂滴和线粒体，使用分子马达（如驱动蛋白）沿微管运输。许多实验和计算研究集中在具有刚性连接的电机的货物上，与许多具有脂质表面的生物货物形成对比，这些表面可能允许电机的表面移动。我们通过添加耦合粘度效应来扩展机械化学 3D 计算模型，以比较不同的运动安排和流动性。我们表明，组织变化可以针对不同的目标进行优化：具有集群马达的货物运输有效，但与微管结合的速度较慢，而具有刚性分散在其表面上的马达快速结合微管，但运输效率低下。最后，带有自由扩散电机的货物具有快速绑定和高效运输，但效率不如集群电机。这些结果表明，实验观察到的运动组织变化可能是运输的控制点。