βPix-d promotes tubulin acetylation and neurite outgrowth through a PAK/Stathmin1 signaling pathway.

Microtubules are a major cytoskeletal component of neurites, and the regulation of microtubule stability is essential for neurite morphogenesis. βPix (ARHGEF7) is a guanine nucleotide exchange factor for the small GTPases Rac1 and Cdc42, which modulate the organization of actin filaments and microtu...

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Main Authors: Younghee Kwon, Ye Won Jeon, Minjae Kwon, Yongcheol Cho, Dongeun Park, Jung Eun Shin
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2020-01-01
Series:PLoS ONE
Online Access:https://doi.org/10.1371/journal.pone.0230814
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author Younghee Kwon
Ye Won Jeon
Minjae Kwon
Yongcheol Cho
Dongeun Park
Jung Eun Shin
author_facet Younghee Kwon
Ye Won Jeon
Minjae Kwon
Yongcheol Cho
Dongeun Park
Jung Eun Shin
author_sort Younghee Kwon
collection DOAJ
description Microtubules are a major cytoskeletal component of neurites, and the regulation of microtubule stability is essential for neurite morphogenesis. βPix (ARHGEF7) is a guanine nucleotide exchange factor for the small GTPases Rac1 and Cdc42, which modulate the organization of actin filaments and microtubules. βPix is expressed as alternatively spliced variants, including the ubiquitous isoform βPix-a and the neuronal isoforms βPix-b and βPix-d, but the function of the neuronal isoforms remains unclear. Here, we reveal the novel role of βPix neuronal isoforms in regulating tubulin acetylation and neurite outgrowth. At DIV4, hippocampal neurons cultured from βPix neuronal isoform knockout (βPix-NIKO) mice exhibit defects in neurite morphology and tubulin acetylation, a type of tubulin modification which often labels stable microtubules. Treating βPix-NIKO neurons with paclitaxel, which stabilizes the microtubules, or reintroducing either neuronal βPix isoform to the KO neurons overcomes the impairment in neurite morphology and tubulin acetylation, suggesting that neuronal βPix isoforms may promote microtubule stabilization during neurite development. βPix-NIKO neurons also exhibit lower phosphorylation levels for Stathmin1, a microtubule-destabilizing protein, at Ser16. Expressing either βPix neuronal isoform in the βPix-NIKO neurons restores Stathmin1 phosphorylation levels, with βPix-d having a greater effect than βPix-b. Furthermore, we find that the recovery of neurite length and Stathmin1 phosphorylation via βPix-d expression requires PAK kinase activity. Taken together, our study demonstrates that βPix-d regulates the phosphorylation of Stathmin1 in a PAK-dependent manner and that neuronal βPix isoforms promote tubulin acetylation and neurite morphogenesis during neuronal development.
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spelling doaj.art-49d51f4a96e44dfaa1d96f6989d9d4f12022-12-21T22:38:28ZengPublic Library of Science (PLoS)PLoS ONE1932-62032020-01-01154e023081410.1371/journal.pone.0230814βPix-d promotes tubulin acetylation and neurite outgrowth through a PAK/Stathmin1 signaling pathway.Younghee KwonYe Won JeonMinjae KwonYongcheol ChoDongeun ParkJung Eun ShinMicrotubules are a major cytoskeletal component of neurites, and the regulation of microtubule stability is essential for neurite morphogenesis. βPix (ARHGEF7) is a guanine nucleotide exchange factor for the small GTPases Rac1 and Cdc42, which modulate the organization of actin filaments and microtubules. βPix is expressed as alternatively spliced variants, including the ubiquitous isoform βPix-a and the neuronal isoforms βPix-b and βPix-d, but the function of the neuronal isoforms remains unclear. Here, we reveal the novel role of βPix neuronal isoforms in regulating tubulin acetylation and neurite outgrowth. At DIV4, hippocampal neurons cultured from βPix neuronal isoform knockout (βPix-NIKO) mice exhibit defects in neurite morphology and tubulin acetylation, a type of tubulin modification which often labels stable microtubules. Treating βPix-NIKO neurons with paclitaxel, which stabilizes the microtubules, or reintroducing either neuronal βPix isoform to the KO neurons overcomes the impairment in neurite morphology and tubulin acetylation, suggesting that neuronal βPix isoforms may promote microtubule stabilization during neurite development. βPix-NIKO neurons also exhibit lower phosphorylation levels for Stathmin1, a microtubule-destabilizing protein, at Ser16. Expressing either βPix neuronal isoform in the βPix-NIKO neurons restores Stathmin1 phosphorylation levels, with βPix-d having a greater effect than βPix-b. Furthermore, we find that the recovery of neurite length and Stathmin1 phosphorylation via βPix-d expression requires PAK kinase activity. Taken together, our study demonstrates that βPix-d regulates the phosphorylation of Stathmin1 in a PAK-dependent manner and that neuronal βPix isoforms promote tubulin acetylation and neurite morphogenesis during neuronal development.https://doi.org/10.1371/journal.pone.0230814
spellingShingle Younghee Kwon
Ye Won Jeon
Minjae Kwon
Yongcheol Cho
Dongeun Park
Jung Eun Shin
βPix-d promotes tubulin acetylation and neurite outgrowth through a PAK/Stathmin1 signaling pathway.
PLoS ONE
title βPix-d promotes tubulin acetylation and neurite outgrowth through a PAK/Stathmin1 signaling pathway.
title_full βPix-d promotes tubulin acetylation and neurite outgrowth through a PAK/Stathmin1 signaling pathway.
title_fullStr βPix-d promotes tubulin acetylation and neurite outgrowth through a PAK/Stathmin1 signaling pathway.
title_full_unstemmed βPix-d promotes tubulin acetylation and neurite outgrowth through a PAK/Stathmin1 signaling pathway.
title_short βPix-d promotes tubulin acetylation and neurite outgrowth through a PAK/Stathmin1 signaling pathway.
title_sort βpix d promotes tubulin acetylation and neurite outgrowth through a pak stathmin1 signaling pathway
url https://doi.org/10.1371/journal.pone.0230814
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