# Limited processivity of single motors improves overall transport flux of self-assembled motor-cargo complexes

## TL;DR

This paper presents a new theory showing that low processivity of molecular motors can enhance cellular cargo transport efficiency, challenging the assumption that higher processivity always improves transport.

## Contribution

The study introduces a stochastic model demonstrating that low motor processivity can optimize cargo flux in cellular transport, providing a new perspective on motor function.

## Key findings

- Low processivity can maximize cargo transport flux.
- Infinite processivity does not necessarily improve transport efficiency.
- Weak motor binding to microtubules can be beneficial for cellular transport.

## Abstract

Single kinesin molecular motors can processively move along a microtubule (MT) a few micrometers on average before dissociating. However, cellular length scales over which transport occurs are several hundred microns and more. Why seemingly unreliable motors are used to transport cellular cargo remains poorly understood. We propose a new theory for how low processivity, the average length of a single bout of directed motion, can enhance cellular transport when motors and cargoes must first diffusively self assemble into complexes. We employ stochastic modeling to determine the effect of processivity on overall cargo transport flux. We show that, under a wide range of physiologically relevant conditions, possessing "infinite" processivity does not maximize flux along MTs. Rather, we find that low processivity i.e., weak binding of motors to MTs, is optimal. These results shed light on the relationship between processivity and transport efficiency and offer a new theory for the physiological benefits of low motor processivity.