ID 110106
Title Alternative
GADD34のC末端領域はCHO-K1細胞におけるeIF2αの脱リン酸化および細胞増殖を調節する
eIF2α dephosphorylation and cell proliferation in CHO-K1 cells
Author
Otsuka, Ryo Tokushima University
Aoki, Shouhei Tokushima University
Shirai, Kanna Tokushima University
Nozaki, Ayane Tokushima University
Hatakeyama, Adzumi Tokushima University
Keywords
CHO-K1 cell
GADD34
eIF2α
GSK3β
dephosphorylation
proliferation
Content Type
Thesis or Dissertation
Description
GADD34 is a member of a growth arrest and DNA damage (GADD)-inducible gene family. Here, we established a novel Chinese hamster ovary (CHO-K1)-K1-derived cell line, CHO-K1-G34M, which carries a nonsense mutation (termed the Q525X mutation) in the GADD34 gene. The Q525X mutant protein lacks the C-terminal 66 amino acids required for GADD34 to bind to and activate protein phosphatase 1 (PP1). We investigated the effects of GADD34 with or without the Q525X mutation on the phosphorylation status of PP1 target proteins, including the α subunit of eukaryotic initiation factor 2 (eIF2α) and glycogen synthase kinase 3β (GSK3β). CHOK1-G34M cells had higher levels of eIF2α phosphorylation compared to the control CHO-K1-normal cells both in the presence and absence of endoplasmic reticulum stress. Overexpression of wild type GADD34 protein in CHOK1-normal cells largely reduced eIF2α phosphorylation, while overexpression of the Q525X mutant did not produce similar reductions. Meanwhile, neither wild type nor Q525X mutation of GADD34 affected the GSK3β phosphorylation status. GADD34 also did not affect the canonical Wnt signaling pathway downstream of GSK3β. Cell proliferation rates were higher, while expression levels of the cyclin dependent kinase inhibitor p21 were lower in CHO-K1-G34M cells compared to the CHO-K1-normal cells. The GADD34 Q525X mutant had a reduced ability to inhibit cell proliferation and enhance p21 expression of the CHO-K1-normal cells compared to the wild type GADD34 protein. These results suggest that the GADD34 protein C-terminal plays important roles in regulating not only eIF2α dephosphorylation but also cell proliferation in CHO-K1 cells.
Journal Title
Cell Stress and Chaperones
ISSN
13558145
14661268
NCID
AA11111235
Publisher
Springer Netherlands
Volume
21
Issue
1
Start Page
29
End Page
40
Published Date
2015-08-30
Remark
内容要旨・審査要旨・論文本文の公開:
内容要旨:LID201705231002.pdf
審査要旨:LID201705231003.pdf
論文本文:LID201705251002.pdf
The final publication is available at Springer via https://doi.org/10.1007/s12192-015-0633-9.
本論文は,著者Ryo Otsukaの学位論文として提出され,学位審査・授与の対象となっている。
EDB ID
DOI (Published Version)
URL ( Publisher's Version )
FullText File
language
eng
TextVersion
ETD
MEXT report number
甲第3086号
Diploma Number
甲口第429号
Granted Date
2017-03-23
Degree Name
Doctor of Dental Science
Grantor
Tokushima University
departments
Medical Sciences
Technical Support Department
Oral Sciences