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Different contributions of nonmuscle myosin IIA and IIB to the organization of stress fiber subtypes in fibroblasts

Stress fibers (SFs) are contractile, force-generating bundled structures that can be classified into three subtypes, namely ventral SFs (vSFs), transverse arcs (TAs), and dorsal SFs. Nonmuscle myosin II (NMII) is the main component of SFs. This study examined the roles of the NMII isoforms NMIIA and...

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Autores principales: Kuragano, Masahiro, Uyeda, Taro Q. P., Kamijo, Keiju, Murakami, Yota, Takahashi, Masayuki
Formato: Online Artículo Texto
Lenguaje:English
Publicado: The American Society for Cell Biology 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5896930/
https://www.ncbi.nlm.nih.gov/pubmed/29467250
http://dx.doi.org/10.1091/mbc.E17-04-0215
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author Kuragano, Masahiro
Uyeda, Taro Q. P.
Kamijo, Keiju
Murakami, Yota
Takahashi, Masayuki
author_facet Kuragano, Masahiro
Uyeda, Taro Q. P.
Kamijo, Keiju
Murakami, Yota
Takahashi, Masayuki
author_sort Kuragano, Masahiro
collection PubMed
description Stress fibers (SFs) are contractile, force-generating bundled structures that can be classified into three subtypes, namely ventral SFs (vSFs), transverse arcs (TAs), and dorsal SFs. Nonmuscle myosin II (NMII) is the main component of SFs. This study examined the roles of the NMII isoforms NMIIA and NMIIB in the organization of each SF subtype in immortalized fibroblasts. Knockdown (KD) of NMIIA (a major isoform) resulted in loss of TAs from the lamella and caused the lamella to lose its flattened shape. Exogenous expression of NMIIB rescued this defect in TA formation. However, the TAs that formed on exogenous NMIIB expression in NMIIA-KD cells and the remaining TAs in NMIIB-KD cells, which mainly consisted of NMIIB and NMIIA, respectively, failed to rescue the defect in lamellar flattening. These results indicate that both isoforms are required for the proper function of TAs in lamellar flattening. KD of NMIIB resulted in loss of vSFs from the central region of the cell body, and this defect was not rescued by exogenous expression of NMIIA, indicating that NMIIA cannot replace the function of NMIIB in vSF formation. Moreover, we raised the possibility that actin filaments in vSFs are in a stretched conformation.
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spelling pubmed-58969302018-06-30 Different contributions of nonmuscle myosin IIA and IIB to the organization of stress fiber subtypes in fibroblasts Kuragano, Masahiro Uyeda, Taro Q. P. Kamijo, Keiju Murakami, Yota Takahashi, Masayuki Mol Biol Cell Articles Stress fibers (SFs) are contractile, force-generating bundled structures that can be classified into three subtypes, namely ventral SFs (vSFs), transverse arcs (TAs), and dorsal SFs. Nonmuscle myosin II (NMII) is the main component of SFs. This study examined the roles of the NMII isoforms NMIIA and NMIIB in the organization of each SF subtype in immortalized fibroblasts. Knockdown (KD) of NMIIA (a major isoform) resulted in loss of TAs from the lamella and caused the lamella to lose its flattened shape. Exogenous expression of NMIIB rescued this defect in TA formation. However, the TAs that formed on exogenous NMIIB expression in NMIIA-KD cells and the remaining TAs in NMIIB-KD cells, which mainly consisted of NMIIB and NMIIA, respectively, failed to rescue the defect in lamellar flattening. These results indicate that both isoforms are required for the proper function of TAs in lamellar flattening. KD of NMIIB resulted in loss of vSFs from the central region of the cell body, and this defect was not rescued by exogenous expression of NMIIA, indicating that NMIIA cannot replace the function of NMIIB in vSF formation. Moreover, we raised the possibility that actin filaments in vSFs are in a stretched conformation. The American Society for Cell Biology 2018-04-15 /pmc/articles/PMC5896930/ /pubmed/29467250 http://dx.doi.org/10.1091/mbc.E17-04-0215 Text en © 2018 Kuragano et al. “ASCB®,” “The American Society for Cell Biology®,” and “Molecular Biology of the Cell®” are registered trademarks of The American Society for Cell Biology. http://creativecommons.org/licenses/by-nc-sa/3.0/ This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License.
spellingShingle Articles
Kuragano, Masahiro
Uyeda, Taro Q. P.
Kamijo, Keiju
Murakami, Yota
Takahashi, Masayuki
Different contributions of nonmuscle myosin IIA and IIB to the organization of stress fiber subtypes in fibroblasts
title Different contributions of nonmuscle myosin IIA and IIB to the organization of stress fiber subtypes in fibroblasts
title_full Different contributions of nonmuscle myosin IIA and IIB to the organization of stress fiber subtypes in fibroblasts
title_fullStr Different contributions of nonmuscle myosin IIA and IIB to the organization of stress fiber subtypes in fibroblasts
title_full_unstemmed Different contributions of nonmuscle myosin IIA and IIB to the organization of stress fiber subtypes in fibroblasts
title_short Different contributions of nonmuscle myosin IIA and IIB to the organization of stress fiber subtypes in fibroblasts
title_sort different contributions of nonmuscle myosin iia and iib to the organization of stress fiber subtypes in fibroblasts
topic Articles
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5896930/
https://www.ncbi.nlm.nih.gov/pubmed/29467250
http://dx.doi.org/10.1091/mbc.E17-04-0215
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