She1 affects dynein through direct interactions with the microtubule and the dynein microtubule-binding domain

Kari H Ecklund,Timothy J Stasevich,Tatsuya Morisaki,Steven M Markus,Matthew G Marzo,Lindsay G Lammers

doi:10.1038/s41467-017-02004-2

Kari H Ecklund, Timothy J Stasevich + Show 4 more

Open Access

https://doi.org/10.1038/s41467-017-02004-2

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Journal: Nature Communications	Publication Date: Dec 1, 2017
Citations: 26	License type: open-access

Affiliation: Colorado State University

Abstract

Cytoplasmic dynein is an enormous minus end-directed microtubule motor. Rather than existing as bare tracks, microtubules are bound by numerous microtubule-associated proteins (MAPs) that have the capacity to affect various cellular functions, including motor-mediated transport. One such MAP is She1, a dynein effector that polarizes dynein-mediated spindle movements in budding yeast. Here, we characterize the molecular basis by which She1 affects dynein, providing the first such insight into which a MAP can modulate motor motility. We find that She1 affects the ATPase rate, microtubule-binding affinity, and stepping behavior of dynein, and that microtubule binding by She1 is required for its effects on dynein motility. Moreover, we find that She1 directly contacts the microtubule-binding domain of dynein, and that their interaction is sensitive to the nucleotide-bound state of the motor. Our data support a model in which simultaneous interactions between the microtubule and dynein enables She1 to directly affect dynein motility.

Highlights

Cytoplasmic dynein is an enormous minus end-directed microtubule motor
Rather than existing as bare tracks, microtubules are bound by various classes of microtubule-associated proteins (MAPs), including those that bind along the lattice (e.g., MAP1A, tau, TPX2, PRC12–5), those that concentrate at the plus (e.g., EB1, CLIP170, CLASP6–8) or minus ends (e.g., Patronin9), and a large number of microtubule motors
The crowded microenvironment of the microtubule lattice raises the possibility that MAPs may regulate dynein activity via direct interactions with regions of the motor that are in close proximity to the microtubule (i.e., the microtubule-binding domain, MTBD, or the coiled coil (CC) that links the MTBD to the AAA ring)

Summary

Introduction

Cytoplasmic dynein is an enormous minus end-directed microtubule motor. Rather than existing as bare tracks, microtubules are bound by numerous microtubule-associated proteins (MAPs) that have the capacity to affect various cellular functions, including motormediated transport. Given its varied cellular roles it is unsurprising that numerous regulators contribute to in vivo dynein function These include LIS1 (human homolog of yeast Pac1), the dynactin complex, and the growing family of adapter proteins that link dynein to dynactin and various cellular sites (e.g., Bicaudal-D, Hook, Spindly). The crowded microenvironment of the microtubule lattice raises the possibility that MAPs may regulate dynein activity via direct interactions with regions of the motor that are in close proximity to the microtubule (i.e., the microtubule-binding domain, MTBD, or the coiled coil (CC) that links the MTBD to the AAA ring). No such activity has yet been identified

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