Abstract
The ubiquitin-proteasome system regulates the abundance of many cellular proteins by mediating their targeted degradation. We previously developed a method— differential proteomics–based identification of ubiquitylation substrates (DiPIUS)—for the comprehensive identification of substrates for a given F-box protein subunit of SCF-type ubiquitin ligases. We have now applied DiPIUS to the F-box protein Fbxw7 in three cell lines (mHepa, Neuro2A, and C2C12) and thereby identified myelin regulatory factor (MyRF), an endoplasmic reticulum–anchored transcription factor that is essential for myelination of nerves in the central nervous system, as a candidate substrate of Fbxw7 specifically in mHepa cells. Co-immunoprecipitation analysis confirmed that the NH2-terminal cytoplasmic domain of MyRF interacted with Fbxw7 in these cells. Furthermore, an in vitro ubiquitylation assay revealed that MyRF undergoes polyubiqui-tylation in the presence of purified recombinant SCFFbxw7. In addition, the stability of MyRF in mHepa cells was increased by mutation of a putative phosphodegron sequence or by exposure of the cells to an inhibitor of glycogen synthase kinase-3 (GSK-3). We found that MyRF mRNA is not restricted to the central nervous system but is instead distributed widely among mouse tissues. Furthermore, with the use of RNA sequencing in mHepa cells overexpressing or depleted of MyRF, we identified many novel potential target genes of MyRF. Our results thus suggest that Fbxw7 controls the transcription of MyRF target genes in various tissues through regulation of MyRF protein stability in a manner dependent on MyRF phosphorylation by GSK-3.
| Original language | English |
|---|---|
| Pages (from-to) | 5705-5714 |
| Number of pages | 10 |
| Journal | Journal of Biological Chemistry |
| Volume | 293 |
| Issue number | 15 |
| DOIs | |
| Publication status | Published - Jan 1 2018 |
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All Science Journal Classification (ASJC) codes
- Biochemistry
- Molecular Biology
- Cell Biology
Cite this
Degradation of the endoplasmic reticulum–anchored transcription factor MyRF by the ubiquitin ligase SCFFbxw7 in a manner dependent on the kinase GSK-3. / Nakayama, Shogo; Yumimoto, Kanae; Kawamura, Atsuki; Nakayama, Keiichi.
In: Journal of Biological Chemistry, Vol. 293, No. 15, 01.01.2018, p. 5705-5714.Research output: Contribution to journal › Article
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TY - JOUR
T1 - Degradation of the endoplasmic reticulum–anchored transcription factor MyRF by the ubiquitin ligase SCFFbxw7 in a manner dependent on the kinase GSK-3
AU - Nakayama, Shogo
AU - Yumimoto, Kanae
AU - Kawamura, Atsuki
AU - Nakayama, Keiichi
PY - 2018/1/1
Y1 - 2018/1/1
N2 - The ubiquitin-proteasome system regulates the abundance of many cellular proteins by mediating their targeted degradation. We previously developed a method— differential proteomics–based identification of ubiquitylation substrates (DiPIUS)—for the comprehensive identification of substrates for a given F-box protein subunit of SCF-type ubiquitin ligases. We have now applied DiPIUS to the F-box protein Fbxw7 in three cell lines (mHepa, Neuro2A, and C2C12) and thereby identified myelin regulatory factor (MyRF), an endoplasmic reticulum–anchored transcription factor that is essential for myelination of nerves in the central nervous system, as a candidate substrate of Fbxw7 specifically in mHepa cells. Co-immunoprecipitation analysis confirmed that the NH2-terminal cytoplasmic domain of MyRF interacted with Fbxw7 in these cells. Furthermore, an in vitro ubiquitylation assay revealed that MyRF undergoes polyubiqui-tylation in the presence of purified recombinant SCFFbxw7. In addition, the stability of MyRF in mHepa cells was increased by mutation of a putative phosphodegron sequence or by exposure of the cells to an inhibitor of glycogen synthase kinase-3 (GSK-3). We found that MyRF mRNA is not restricted to the central nervous system but is instead distributed widely among mouse tissues. Furthermore, with the use of RNA sequencing in mHepa cells overexpressing or depleted of MyRF, we identified many novel potential target genes of MyRF. Our results thus suggest that Fbxw7 controls the transcription of MyRF target genes in various tissues through regulation of MyRF protein stability in a manner dependent on MyRF phosphorylation by GSK-3.
AB - The ubiquitin-proteasome system regulates the abundance of many cellular proteins by mediating their targeted degradation. We previously developed a method— differential proteomics–based identification of ubiquitylation substrates (DiPIUS)—for the comprehensive identification of substrates for a given F-box protein subunit of SCF-type ubiquitin ligases. We have now applied DiPIUS to the F-box protein Fbxw7 in three cell lines (mHepa, Neuro2A, and C2C12) and thereby identified myelin regulatory factor (MyRF), an endoplasmic reticulum–anchored transcription factor that is essential for myelination of nerves in the central nervous system, as a candidate substrate of Fbxw7 specifically in mHepa cells. Co-immunoprecipitation analysis confirmed that the NH2-terminal cytoplasmic domain of MyRF interacted with Fbxw7 in these cells. Furthermore, an in vitro ubiquitylation assay revealed that MyRF undergoes polyubiqui-tylation in the presence of purified recombinant SCFFbxw7. In addition, the stability of MyRF in mHepa cells was increased by mutation of a putative phosphodegron sequence or by exposure of the cells to an inhibitor of glycogen synthase kinase-3 (GSK-3). We found that MyRF mRNA is not restricted to the central nervous system but is instead distributed widely among mouse tissues. Furthermore, with the use of RNA sequencing in mHepa cells overexpressing or depleted of MyRF, we identified many novel potential target genes of MyRF. Our results thus suggest that Fbxw7 controls the transcription of MyRF target genes in various tissues through regulation of MyRF protein stability in a manner dependent on MyRF phosphorylation by GSK-3.
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UR - http://www.scopus.com/inward/citedby.url?scp=85045377203&partnerID=8YFLogxK
U2 - 10.1074/jbc.RA117.000741
DO - 10.1074/jbc.RA117.000741
M3 - Article
VL - 293
SP - 5705
EP - 5714
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
SN - 0021-9258
IS - 15
ER -