Gene/Protein
Disease
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Enzyme
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Pivot Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
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Target Concepts:
Gene/Protein
Disease
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Query: EC:2.7.7.49 (
reverse transcriptase
)
31,746
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Among the four isoforms of the calcitonin receptor (CTR) described in humans, two differ by the presence of h-CTR1 or absence of h-
CTR2
of 16 amino acids in the first intracellular loop. Both receptors are biologically active. The TT cell line derived from a human medullary carcinoma of the thyroid is characterized by the secretion of large amounts of calcitonin. We have recently shown that this cell line expresses h-
CTR2
. In the present work we have studied the expression of CTR during TT cell proliferation and used dexamethasone to modify calcitonin expression in order to establish if an autocrine regulation involving calcitonin and its receptor was functional in the TT cells. The expression of this receptor and of calcitonin during TT cell proliferation was studied by
reverse transcriptase
-polymerase chain reaction (RT-PCR). Dexamethasone, a potent inhibitor of TT cell proliferation, levels (day 6 of culture) specifically increased receptor levels from day 8 onwards. CT peptide and CT mRNA levels decreased or were similar during experimental time. CTR regulation by glucocorticoids is suggested in TT cells. Autocrine regulation of CTR is also suggested by relation between CT mRNA levels and CTR mRNA.
...
PMID:Calcitonin receptor mRNA expression in TT cells: effect of dexamethasone. 970 72
Down-regulation of copper transporter 1 (CTR1) reduces uptake and sensitivity, whereas down-regulation of
CTR2
enhances both. Cisplatin (DDP) triggers the rapid degradation of CTR1 and thus limits its own accumulation. We sought to determine the effect of DDP and copper on the expression of
CTR2
. Changes in CTR1 and
CTR2
mRNA and protein levels in human ovarian carcinoma 2008 cells and ATOX1(+/+) and ATOX1(-/-) mouse embryo fibroblasts in response to exposure to DDP and copper were measured by quantitative
reverse transcriptase
-polymerase chain reaction, Western blot analysis, and deconvolution microscopy. DDP triggered rapid degradation of CTR1 in 2008 human ovarian cancer cells. However, it increased the expression of
CTR2
mRNA and protein levels. Expression of
CTR2
was heavily modulated by changes in intracellular copper concentration; copper depletion produced rapid disappearance of
CTR2
, whereas excess copper increased the level of
CTR2
protein. This increase was associated with an increase in
CTR2
mRNA and prolongation of the
CTR2
half-life. Consistent with prior observations that short hairpin RNA interference-mediated knockdown of
CTR2
enhanced DDP uptake and tumor cell kill, reduction of
CTR2
by copper starvation also enhanced DDP uptake and cytotoxicity. Comparison of the ability of copper and DDP to modulate the expression of CTR1 in ATOX1(+/+) and ATOX1(-/-) indicated that ATOX1 participates in the regulation of
CTR2
expression. Unlike CTR1, the expression of
CTR2
is increased rather than decreased by DDP. Therefore, these two copper transporters have opposite effects on DDP sensitivity.
CTR2
expression is regulated by copper availability via the copper-dependent regulator ATOX1.
...
PMID:Regulation of copper transporter 2 expression by copper and cisplatin in human ovarian carcinoma cells. 2019 31
