TY - JOUR
T1 - Different contributions of nonmuscle myosin IIA and IIB to the organization of stress fiber subtypes in fibroblasts
AU - Kuragano, Masahiro
AU - Uyeda, Taro Q.P.
AU - Kamijo, Keiju
AU - Murakami, Yota
AU - Takahashi, Masayuki
AU - Wang, Yu Li
N1 - Funding Information:
We are grateful to the Nikon Imaging Center (Hokkaido University) for assistance with microscopy, image acquisition, and analysis. We are also grateful to Hisashi Haga (Hokkaido University) and Takeomi Mizutani (Hokkai-Gakuen University, Sapporo, Japan) for helpful advice on the cell stretching assay. This work was supported by Grants-in-Aid for Scientific Research from the Japan Society for the Promotion of Science (JSPS) (no. 25440061 to M.T.). Part of this work was supported by the "Nanotechnology Platform" Program of the Ministry of Education, Culture, Sports, Science, and Technology (MEXT), Japan, and also by JSPS KAKENHI Grant Number JP16H06280, a Grant-in-Aid for Scientific Research on Innovative Areas-Resource, and technical support platforms for promoting research "Advanced Bioimaging Support."
Funding Information:
was supported by the “Nanotechnology Platform” Program of the Ministry of Education, Culture, Sports, Science, and Technology (MEXT), Japan, and also by JSPS KAKENHI Grant Number JP16H06280, a Grant-in-Aid for Scientific Research on Innovative Areas-Resource, and technical support platforms for promoting research “Advanced Bioimaging Support.”
Funding Information:
We are grateful to the Nikon Imaging Center (Hokkaido University) for assistance with microscopy, image acquisition, and analysis. We are also grateful to Hisashi Haga (Hokkaido University) and Takeomi Mizutani (Hokkai-Gakuen University, Sapporo, Japan) for helpful advice on the cell stretching assay. This work was supported by Grants-in-Aid for Scientific Research from the Japan Society for the Promotion of Science (JSPS) (no. 25440061 to M.T.). Part of this work
Publisher Copyright:
© 2018 Kuragano et al.
PY - 2018/4/15
Y1 - 2018/4/15
N2 - 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.
AB - 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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U2 - 10.1091/mbc.E17-04-0215
DO - 10.1091/mbc.E17-04-0215
M3 - Article
C2 - 29467250
AN - SCOPUS:85043510593
VL - 29
SP - 911
EP - 922
JO - Molecular Biology of the Cell
JF - Molecular Biology of the Cell
SN - 1059-1524
IS - 8
ER -