The walkoff effect: cargo distribution implies motor type in bidirectional microtubule bundles

Abstract

Cells rely on molecular motors moving along an ever-shifting network of polymers (microtubules) for the targeted delivery of cell organelles to biologically-relevant locations. We present a stochastic model for a molecular motor stepping along a bidirectional bundle of microtubules, as well as a tractable analytical model. Using these models, we investigate how the preferred stepping direction of the motor (parallel or antiparallel to the microtubule growth, corresponding to kinesin and dynein motor families) quantitatively and qualitatively affects the cargo delivery. We predict which motor type is responsible for which cargo type, given the experimental distribution of cargo in the cell, and report experimental findings which support this guideline for motor classification.

Deciphering the roles of cell shape and Fat and Dachsous planar polarity in arranging the Drosophila apical microtubule network through quantitative image analysis

“…However, they do not exclude changes to the detail of this organization dependent on Ft-Ds activity. The localization of the minus ends in noncentrosomal networks is of particular interest, as it ensures the correct polarized transport by motor proteins ( Steinhauer and Kalderon, 2006 ; Zhelezov et al. , 2019 ).To examine the possibility that Ft-Ds complexes alter the distribution of the minus ends without affecting the overall organization of subapical microtubules, we turned to the minus-end capping protein Patronin, which localizes at apical junctions and exhibits an asymmetrical distribution in the Drosophila embryonic epidermis that depends on the cell elongation ( Goodwin and Vale, 2010 ; Płochocka et al.…”