Identification and characterization of the land-plant-specific microtubule nucleation factor MACET4

Sharol Schmidt; Andrei Smertenko

doi:10.1242/jcs.232819

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Identification and characterization of the land-plant-specific microtubule nucleation factor MACET4

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Identification and characterization of the land-plant-specific microtubule nucleation factor MACET4

Sharol Schmidt and Andrei Smertenko

Journal of cell science, Vol.132(11), p.jcs232819

06/05/2019

DOI: https://doi.org/10.1242/jcs.232819

Handle:

https://hdl.handle.net/2376/115456

PMID: 31076517

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Abstract

Phragmoplast

Nucleation

Cytokinesis

Microtubules

Here, we show that the embryophyte (land-plant)-specific protein MACERATOR4 (MACET4) binds microtubules and , promotes microtubule polymerization at sub-critical tubulin concentrations, decreases the lag phase in microtubule bulk polymerization assays, and colocalizes with microtubule nucleation sites. Furthermore, we find that MACET4 forms oligomers that induce aster formation in a manner that is similar to aster formation mediated by centrosomes and TPX2. MACET4 is expressed during cell division and accumulates at the microtubule nucleation regions of the plant-specific cytokinetic microtubule array, the phragmoplast. We found that MACET4 localizes to the preprophase band and the cortical division zone, but not the spindle. MACET4 appears as cytoplasmic foci and forms octamers Transient expression in tobacco leaf pavement cells results in labeling of shrinking plus- and minus-ends. MACET4 facilitates microtubule depolymerization by increasing the frequency of catastrophes and by suppressing rescues Microtubules formed in the presence of MACET4 are shorter, most likely due to the depletion of the free tubulin pool. Accordingly, MACET4 knockdown results in longer phragmoplasts. We conclude that the direct activity of MACET4 is in promoting microtubule nucleation.This article has an associated First Person interview with the first author of the paper.

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Title: Identification and characterization of the land-plant-specific microtubule nucleation factor MACET4
Creators: Sharol Schmidt - Institute of Biological Chemistry, Washington State University, Pullman, WA 99164, USA
Andrei Smertenko - Institute of Biological Chemistry, Washington State University, Pullman, WA 99164, USA andrei.smertenko@wsu.edu
Publication Details: Journal of cell science, Vol.132(11), p.jcs232819
Academic Unit: Biological Chemistry, Institute of
Publisher: England
Identifiers: 99900547324701842
Language: English
Resource Type: Journal article