Abstract
The degradations of several nuclear receptors are involved in the proteasome-mediated pathway. In our recent experiments, we found that mouse pregnane X receptor (PXR) interacted with suppressor for gal1 (SUG1), a component of the proteasome, in a progesterone-dependent manner, but that endocrine-disrupting chemicals (EDCs), phthalic acid and nonylphenol, which activated PXR-mediated transcription, did not enhance this interaction. PXR protein levels were markedly increased in the presence of proteasome inhibitors, suggesting that PXR may be degraded by proteasome. Furthermore, in the absence of ongoing protein synthesis, there is much slower degradation of PXR in the presence ofphthalic acid compared with that in the presence of progesterone. The transient expression studies demonstrated that overexpression of wild-type SUG1 generated proteolytic PXR fragments, and these productions were blocked by a proteasome inhibitor. Functionally, expression of SUG1 inhibited PXR- and progesterone-mediated transcription. Moreover, in the presence of EDCs, SUG1 had no effect on the transcription. These findings indicate that the interaction between PXR and SUG1 may be involved in the proteasome-mediated degradation. Moreover, an EDC strongly blocks the degradation of PXR compared with progesterone, suggesting that EDCs may affect PXR-mediated transcription of target genes through upregulation of the PXR protein level.
| Original language | English |
|---|---|
| Pages (from-to) | 55-61 |
| Number of pages | 7 |
| Journal | Endocrinology |
| Volume | 143 |
| Issue number | 1 |
| DOIs | |
| Publication status | Published - 2002 |
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ASJC Scopus subject areas
- Endocrinology
- Endocrinology, Diabetes and Metabolism
Cite this
Ligands have various potential effects on the degradation of pregnane X receptor by proteasome. / Masuyama, Hisashi; Inoshita, Hideshi; Hiramatsu, Yuji; Kudo, Takafumi.
In: Endocrinology, Vol. 143, No. 1, 2002, p. 55-61.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Ligands have various potential effects on the degradation of pregnane X receptor by proteasome
AU - Masuyama, Hisashi
AU - Inoshita, Hideshi
AU - Hiramatsu, Yuji
AU - Kudo, Takafumi
PY - 2002
Y1 - 2002
N2 - The degradations of several nuclear receptors are involved in the proteasome-mediated pathway. In our recent experiments, we found that mouse pregnane X receptor (PXR) interacted with suppressor for gal1 (SUG1), a component of the proteasome, in a progesterone-dependent manner, but that endocrine-disrupting chemicals (EDCs), phthalic acid and nonylphenol, which activated PXR-mediated transcription, did not enhance this interaction. PXR protein levels were markedly increased in the presence of proteasome inhibitors, suggesting that PXR may be degraded by proteasome. Furthermore, in the absence of ongoing protein synthesis, there is much slower degradation of PXR in the presence ofphthalic acid compared with that in the presence of progesterone. The transient expression studies demonstrated that overexpression of wild-type SUG1 generated proteolytic PXR fragments, and these productions were blocked by a proteasome inhibitor. Functionally, expression of SUG1 inhibited PXR- and progesterone-mediated transcription. Moreover, in the presence of EDCs, SUG1 had no effect on the transcription. These findings indicate that the interaction between PXR and SUG1 may be involved in the proteasome-mediated degradation. Moreover, an EDC strongly blocks the degradation of PXR compared with progesterone, suggesting that EDCs may affect PXR-mediated transcription of target genes through upregulation of the PXR protein level.
AB - The degradations of several nuclear receptors are involved in the proteasome-mediated pathway. In our recent experiments, we found that mouse pregnane X receptor (PXR) interacted with suppressor for gal1 (SUG1), a component of the proteasome, in a progesterone-dependent manner, but that endocrine-disrupting chemicals (EDCs), phthalic acid and nonylphenol, which activated PXR-mediated transcription, did not enhance this interaction. PXR protein levels were markedly increased in the presence of proteasome inhibitors, suggesting that PXR may be degraded by proteasome. Furthermore, in the absence of ongoing protein synthesis, there is much slower degradation of PXR in the presence ofphthalic acid compared with that in the presence of progesterone. The transient expression studies demonstrated that overexpression of wild-type SUG1 generated proteolytic PXR fragments, and these productions were blocked by a proteasome inhibitor. Functionally, expression of SUG1 inhibited PXR- and progesterone-mediated transcription. Moreover, in the presence of EDCs, SUG1 had no effect on the transcription. These findings indicate that the interaction between PXR and SUG1 may be involved in the proteasome-mediated degradation. Moreover, an EDC strongly blocks the degradation of PXR compared with progesterone, suggesting that EDCs may affect PXR-mediated transcription of target genes through upregulation of the PXR protein level.
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U2 - 10.1210/en.143.1.55
DO - 10.1210/en.143.1.55
M3 - Article
VL - 143
SP - 55
EP - 61
JO - Endocrinology
JF - Endocrinology
SN - 0013-7227
IS - 1
ER -