Thyroglobulin (Tg) activates MAPK pathway to induce thyroid cell growth in the absence of TSH, insulin and serum

Mariko Sue, Moyuru Hayashi, Akira Kawashima, Takeshi Akama, Kazunari Tanigawa, Aya Yoshihara, Takeshi Hara, Yuko Ishido, Tetsuhide Ito, Shin Ichiro Takahashi, Norihisa Ishii, Koichi Suzuki

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6 Citations (Scopus)

Abstract

The growth of thyroid cells is tightly regulated by thyroid stimulating hormone (TSH) through the cyclic adenosine 3', 5'-monophosphate (cAMP) signaling pathway by potentiating the mitogenic activity of insulin and insulin-like growth factors (IGFs). However, we recently reported that thyroglobulin (Tg), a major product of the thyroid, also induces the growth of thyroid cells cultured in 0.2% serum in the absence of TSH and insulin. In this report, we demonstrate that Tg induced phosphorylation of molecules of the c-Raf/MEK/ERK pathway of the mitogen-activated protein kinase (MAPK). The MEK-1/2 inhibitor PD98059 suppressed Tg-induced phosphorylation of ERK1/2 and reduced bromodeoxyuridine (BrdU) incorporation. Tg also induced expression of the essential transcriptional factors c-Myc, c-Fos and c-Jun and phosphorylation of the retinoblastoma (Rb) protein. The present results, together with the previous report, suggest that Tg utilizes multiple signaling cascades to induce thyroid cell growth independent of TSH/cAMP stimulation.

Original languageEnglish
Pages (from-to)611-615
Number of pages5
JournalBiochemical and Biophysical Research Communications
Volume420
Issue number3
DOIs
Publication statusPublished - Apr 13 2012

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All Science Journal Classification (ASJC) codes

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology

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