Abstract
TRH binds to a membrane receptor that activates several intracellular signaling pathways and increases transcription of the TSH and prolactin (PRL) genes. Although TRH induces TSH and PRL gene expression, the underlying mechanism is not clear. In this report we examined the role of the Ca 2+/calmodulin-dependent protein (CaM) kinase cascade in mediating TRH-stimulated transcription of TSH and PRL. RT-PCR and Western blot analysis were used to show that CaM kinase kinase (CaM-KK) and CaM IV (CaM-KIV) were present in rat anterior pituitary and its cell line GH3. Next, the effects of constitutively active CaM-KIV (CaM-KIVc) or its dominant negative mutant (CaM-KIVdn) on TSH and PRL promoter activity were tested in GH 3 cells. The results showed that either CaM-KIVc alone or an upstream kinase, CaM-KK, induced the activity of both TSH and PRL promoters. Exposure of GH3 cells to 100 μM TRH induced CaM-KIV activity within 5 min and, as expected, also increased both TSH and PRL promoter activity. In contrast, cells carrying the CaM-KIVdn isoform had suppressed TRH induction of both TSH and PRL promoter activity. These results indicate that the CaM-KK-CaM-KTV cascade probably plays an important role in TRH induction of TSH and PRL transcriptional activity in pituitary cells.
| Original language | English |
|---|---|
| Pages (from-to) | 4846-4852 |
| Number of pages | 7 |
| Journal | Endocrinology |
| Volume | 145 |
| Issue number | 11 |
| DOIs | |
| Publication status | Published - Nov 2004 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Endocrinology
- Endocrinology, Diabetes and Metabolism
Cite this
Role of calcium-calmodulin-dependent protein kinase cascade in thyrotropin (TSH)-releasing hormone induction of TSH and prolactin gene expression. / Murao, Koji; Imachi, Hitomi; Cao, Wen M.; Yu, Xiao; Tokumitsu, Hiroshi; Inuzuka, Hiroyuki; Wong, Norman C W; Shupnik, Margaret A.; Kobayashi, Ryoji; Ishida, Toshihiko.
In: Endocrinology, Vol. 145, No. 11, 11.2004, p. 4846-4852.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Role of calcium-calmodulin-dependent protein kinase cascade in thyrotropin (TSH)-releasing hormone induction of TSH and prolactin gene expression
AU - Murao, Koji
AU - Imachi, Hitomi
AU - Cao, Wen M.
AU - Yu, Xiao
AU - Tokumitsu, Hiroshi
AU - Inuzuka, Hiroyuki
AU - Wong, Norman C W
AU - Shupnik, Margaret A.
AU - Kobayashi, Ryoji
AU - Ishida, Toshihiko
PY - 2004/11
Y1 - 2004/11
N2 - TRH binds to a membrane receptor that activates several intracellular signaling pathways and increases transcription of the TSH and prolactin (PRL) genes. Although TRH induces TSH and PRL gene expression, the underlying mechanism is not clear. In this report we examined the role of the Ca 2+/calmodulin-dependent protein (CaM) kinase cascade in mediating TRH-stimulated transcription of TSH and PRL. RT-PCR and Western blot analysis were used to show that CaM kinase kinase (CaM-KK) and CaM IV (CaM-KIV) were present in rat anterior pituitary and its cell line GH3. Next, the effects of constitutively active CaM-KIV (CaM-KIVc) or its dominant negative mutant (CaM-KIVdn) on TSH and PRL promoter activity were tested in GH 3 cells. The results showed that either CaM-KIVc alone or an upstream kinase, CaM-KK, induced the activity of both TSH and PRL promoters. Exposure of GH3 cells to 100 μM TRH induced CaM-KIV activity within 5 min and, as expected, also increased both TSH and PRL promoter activity. In contrast, cells carrying the CaM-KIVdn isoform had suppressed TRH induction of both TSH and PRL promoter activity. These results indicate that the CaM-KK-CaM-KTV cascade probably plays an important role in TRH induction of TSH and PRL transcriptional activity in pituitary cells.
AB - TRH binds to a membrane receptor that activates several intracellular signaling pathways and increases transcription of the TSH and prolactin (PRL) genes. Although TRH induces TSH and PRL gene expression, the underlying mechanism is not clear. In this report we examined the role of the Ca 2+/calmodulin-dependent protein (CaM) kinase cascade in mediating TRH-stimulated transcription of TSH and PRL. RT-PCR and Western blot analysis were used to show that CaM kinase kinase (CaM-KK) and CaM IV (CaM-KIV) were present in rat anterior pituitary and its cell line GH3. Next, the effects of constitutively active CaM-KIV (CaM-KIVc) or its dominant negative mutant (CaM-KIVdn) on TSH and PRL promoter activity were tested in GH 3 cells. The results showed that either CaM-KIVc alone or an upstream kinase, CaM-KK, induced the activity of both TSH and PRL promoters. Exposure of GH3 cells to 100 μM TRH induced CaM-KIV activity within 5 min and, as expected, also increased both TSH and PRL promoter activity. In contrast, cells carrying the CaM-KIVdn isoform had suppressed TRH induction of both TSH and PRL promoter activity. These results indicate that the CaM-KK-CaM-KTV cascade probably plays an important role in TRH induction of TSH and PRL transcriptional activity in pituitary cells.
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U2 - 10.1210/en.2004-0544
DO - 10.1210/en.2004-0544
M3 - Article
VL - 145
SP - 4846
EP - 4852
JO - Endocrinology
JF - Endocrinology
SN - 0013-7227
IS - 11
ER -