This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Copyright Permission Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Velasco, J. A. Articles by Santisteban, P. Search for Related Content PubMed PubMed Citation Articles by Velasco, J. A. Articles by Santisteban, P.

Ha-ras Interference with Thyroid Cell Differentiation Is Associated with a Down-Regulation of Thyroid Transcription Factor-1 Phosphorylation¹

Instituto de Investigaciones Biomédicas (J.A.V., A.A., J.M.-P., P.S.), Consejo Superior de Investigaciones Científicas, Arturo Duperier 4, 28029 Madrid, Spain; Dipartimento di Biologia e Patologia Cellulare e Molecolare (M.Z.), Universitá degli Studi di Napoli Federico II, 80131 Naples, Italy; and Stazione Zoologica Anton Dohrn (R.D.L.), Villa Comunale, 80121 Naples, Italy

Address all correspondence and requests for reprints to: Dr. Pilar Santisteban, Instituto de Investigaciones Biomédicas, Consejo Superior de Investigaciones Científicas, Arturo Duperier 4, 28029 Madrid, Spain. E-mail: PSantisteban{at}biomed.iib.uam.es

Mechanisms responsible for the lack of thyroid-specific differentiation markers in Ha-ras transformed FRTL-5 cells have been investigated. In vivo cell labeling and immunoprecipitation demonstrate that phosphorylation of the thyroid transcription factor-1 (TTF-1) is clearly reduced in thyroid cells transformed with the Ha-ras oncogene. Fingerprinting analysis of phosphotryptic peptides from FRTL-5 and Ha-ras-FRTL-5 cells also reveals a heterogeneous pattern of TTF-1 phosphorylation in the transformed cell line. This heterogeneity is localized in the amino terminal cluster of phosphoserines, as determined by transfection of HeLa cells with TTF-1 mutants in which serine residues have been replaced by alanines. Amplification and nucleotide sequence of the 5'-coding region of the TTF-1 gene in Ha-ras-FRTL-5 cells rule out the possibility that differences in phosphorylation were the consequence of any mutational event affecting residues within the N-terminal protein sequence. Hypophosphorylated TTF-1 is still able to bind its DNA consensus sequence within the thyroglobulin promoter, although a reporter construct whose expression is exclusively dependent on TTF-1 is not transactivated. Transfection of Ha-ras-FRTL-5 cells with an expression vector encoding the cAMP dependent protein kinase A (PKA) catalytic subunit partially reestablishes TTF-1 transcriptional activity. Taken together, these results indicate that the lack of specific thyroid gene expression in Ha-ras-FRTL-5 cells could be a direct consequence of the inability of TTF-1 to promote transcription.

This article has been cited by other articles:

				Y. Maeda, V. Dave, and J. A. Whitsett Transcriptional Control of Lung Morphogenesis Physiol Rev, January 1, 2007; 87(1): 219 - 244. [Abstract] [Full Text] [PDF]

				C. Garcia-Jimenez, M. A. Zaballos, and P. Santisteban DARPP-32 (Dopamine and 3',5'-Cyclic Adenosine Monophosphate-Regulated Neuronal Phosphoprotein) Is Essential for the Maintenance of Thyroid Differentiation Mol. Endocrinol., December 1, 2005; 19(12): 3060 - 3072. [Abstract] [Full Text] [PDF]

				G. De Vita, L. Bauer, V. M. C. da Costa, M. De Felice, M. G. Baratta, M. De Menna, and R. Di Lauro Dose-Dependent Inhibition of Thyroid Differentiation by RAS Oncogenes Mol. Endocrinol., January 1, 2005; 19(1): 76 - 89. [Abstract] [Full Text] [PDF]

				M. deFelice, D. Silberschmidt, R. DiLauro, Y. Xu, S. E. Wert, T. E. Weaver, C. J. Bachurski, J. C. Clark, and J. A. Whitsett TTF-1 Phosphorylation Is Required for Peripheral Lung Morphogenesis, Perinatal Survival, and Tissue-specific Gene Expression J. Biol. Chem., September 12, 2003; 278(37): 35574 - 35583. [Abstract] [Full Text] [PDF]

				M-C.W. Yang, B. Wang, J.C. Weissler, L.R. Margraf, and Y-S. Yang BR22, a 26 kDa thyroid transcription factor-1 associated protein (TAP26), is expressed in human lung cells Eur. Respir. J., July 1, 2003; 22(1): 28 - 34. [Abstract] [Full Text] [PDF]

				D. L. Medina, M. Rivas, P. Cruz, I. Barroso, J. Regadera, and P. Santisteban RhoA Activation Promotes Transformation and Loss of Thyroid Cell Differentiation Interfering with Thyroid Transcription Factor-1 Activity Mol. Endocrinol., January 1, 2002; 16(1): 33 - 44. [Abstract] [Full Text] [PDF]

				R. Lonigro, D. Donnini, E. Zappia, G. Damante, M. E. Bianchi, and S. Guazzi Nestin Is a Neuroepithelial Target Gene of Thyroid Transcription Factor-1, a Homeoprotein Required for Forebrain Organogenesis J. Biol. Chem., December 14, 2001; 276(51): 47807 - 47813. [Abstract] [Full Text] [PDF]

				Y.-S. Yang, M.-C. W. Yang, B. Wang, and J. C. Weissler BR22, a Novel Protein, Interacts with Thyroid Transcription Factor-1 and Activates the Human Surfactant Protein B Promoter Am. J. Respir. Cell Mol. Biol., January 1, 2001; 24(1): 30 - 37. [Abstract] [Full Text]

				L. Perrone, G. Tell, and R. Di Lauro Calreticulin Enhances the Transcriptional Activity of Thyroid Transcription Factor-1 by Binding to Its Homeodomain J. Biol. Chem., February 19, 1999; 274(8): 4640 - 4645. [Abstract] [Full Text] [PDF]