共查询到20条相似文献,搜索用时 93 毫秒
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RhoA activation promotes transformation and loss of thyroid cell differentiation interfering with thyroid transcription factor-1 activity. 总被引:1,自引:0,他引:1
Diego L Medina Marcos Rivas Patricia Cruz Isabel Barroso Javier Regadera Pilar Santisteban 《Molecular endocrinology (Baltimore, Md.)》2002,16(1):33-44
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TTF-2, a new forkhead protein, shows a temporal expression in the developing thyroid which is consistent with a role in controlling the onset of differentiation. 总被引:8,自引:0,他引:8 下载免费PDF全文
M Zannini V Avantaggiato E Biffali M I Arnone K Sato M Pischetola B A Taylor S J Phillips A Simeone R Di Lauro 《The EMBO journal》1997,16(11):3185-3197
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Thyroglobulin repression of thyroid transcription factor 1 (TTF-1) gene expression is mediated by decreased DNA binding of nuclear factor I proteins which control constitutive TTF-1 expression 总被引:2,自引:0,他引:2 下载免费PDF全文
Nakazato M Chung HK Ulianich L Grassadonia A Suzuki K Kohn LD 《Molecular and cellular biology》2000,20(22):8499-8512
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L Ortiz P Aza-Blanc M Zannini A C Cato P Santisteban 《The Journal of biological chemistry》1999,274(21):15213-15221
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We recently reported that megalin (gp330), an endocytic receptor found on the apical surface of thyroid cells, binds thyroglobulin (Tg) with high affinity in solid phase assays. Megalin-bound Tg was releasable by heparin. Here we show that Fisher rat thyroid (FRTL-5) cells, a differentiated rat thyroid cell line, can bind and endocytose Tg via megalin. We first demonstrated that FRTL-5 cells express megalin in a thyroid-stimulating hormone-dependent manner. Evidence of Tg binding to megalin on FRTL-5 cells and on an immortalized rat renal proximal tubule cell line (IRPT cells), was obtained by incubating the cells with 125I-Tg, followed by chemical cross-linking and immunoprecipitation of 125I-Tg with antibodies against megalin. To investigate cell binding further, we developed an assay in which cells were incubated with unlabeled Tg at 4 degrees C, followed by incubation with heparin, which released almost all of the cell-bound Tg into the medium. In solid phase experiments designed to illuminate the mechanism of heparin release, we demonstrated that Tg is a heparin-binding protein, as are several megalin ligands. The amount of Tg released by heparin from FRTL-5 and IRPT cells, measured by enzyme-linked immunosorbent assay (ELISA), was markedly reduced by two megalin competitors, receptor-associated protein (RAP) and 1H2 (monoclonal antibody against megalin), indicating that much of the Tg released by heparin had been bound to megalin ( approximately 60-80%). The amount inhibited by RAP was considered to represent specific binding to megalin, which was saturable and of high affinity (Kd approximately 11.2 nM). Tg endocytosis by FRTL-5 and IRPT cells was demonstrated in experiments in which cells were incubated with unlabeled Tg at 37 degrees C, followed by heparin to remove cell-bound Tg. The amount of Tg internalized (measured by ELISA in the cell lysates) was reduced by RAP and 1H2, indicating that Tg endocytosis is partially mediated by megalin. 相似文献
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Thyroid nuclear factor 1 (TTF-1) contains a homeodomain and displays a novel DNA binding specificity. 总被引:32,自引:3,他引:29 下载免费PDF全文
The cDNA for TTF-1, a thyroid nuclear factor that binds to the promoter of thyroid specific genes, has been cloned. The protein encoded by the cDNA shows binding properties indistinguishable from those of TTF-1 present in nuclear extracts of differentiated rat thyroid cells. The DNA binding domain of TTF-1 is a novel mammalian homeodomain that shows considerable sequence homology to the Drosophila NK-2 homeodomain. TTF-1 mRNA and corresponding binding activity are detected in thyroid and lung. The chromosomal localization of the TTF-1 gene has been determined in humans and mice and corresponds to chromosomes 14 and 12, respectively, demonstrating that the TTF-1 gene is not located within previously described clusters of homeobox-containing genes. 相似文献
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