An anchoring complex recruits katanin for microtubule severing at the plant cortical nucleation sites

Noriyoshi Yagi,David W Ehrhardt,Takehide Kato,Sachihiro Matsunaga,Takashi Hashimoto,Masayoshi Nakamura

doi:10.1038/s41467-021-24067-y

Abstract

Microtubules are severed by katanin at distinct cellular locations to facilitate reorientation or amplification of dynamic microtubule arrays, but katanin targeting mechanisms are poorly understood. Here we show that a centrosomal microtubule-anchoring complex is used to recruit katanin in acentrosomal plant cells. The conserved protein complex of Msd1 (also known as SSX2IP) and Wdr8 is localized at microtubule nucleation sites along the microtubule lattice in interphase Arabidopsis cells. Katanin is recruited to these sites for efficient release of newly formed daughter microtubules. Our cell biological and genetic studies demonstrate that Msd1-Wdr8 acts as a specific katanin recruitment factor to cortical nucleation sites (but not to microtubule crossover sites) and stabilizes the association of daughter microtubule minus ends to their nucleation sites until they become severed by katanin. Molecular coupling of sequential anchoring and severing events by the evolutionarily conserved complex renders microtubule release under tight control of katanin activity.

Highlights

Microtubules are severed by katanin at distinct cellular locations to facilitate reorientation or amplification of dynamic microtubule arrays, but katanin targeting mechanisms are poorly understood
We show that the plant Mitotic spindle disanchored 1 (Msd1)–Wdr[8] complex is used to stabilize nucleation sites on cortical microtubule arrays and to subsequently recruit katanin to these subcellular locations to sever daughter microtubules
We first examined whether Msd[1] and Wdr[8] of Arabidopsis thaliana form heteromeric complexes as reported in non-plant organisms

Summary

Introduction

Microtubules are severed by katanin at distinct cellular locations to facilitate reorientation or amplification of dynamic microtubule arrays, but katanin targeting mechanisms are poorly understood. The conserved protein complex of Msd[1] ( known as SSX2IP) and Wdr[8] is localized at microtubule nucleation sites along the microtubule lattice in interphase Arabidopsis cells. Our cell biological and genetic studies demonstrate that Msd1-Wdr[8] acts as a specific katanin recruitment factor to cortical nucleation sites (but not to microtubule crossover sites) and stabilizes the association of daughter microtubule minus ends to their nucleation sites until they become severed by katanin. We show that the plant Msd1–Wdr[8] complex is used to stabilize nucleation sites on cortical microtubule arrays and to subsequently recruit katanin to these subcellular locations to sever daughter microtubules

Methods

Results

Conclusion