Tissue-specific posttranslational modification allows functional targeting of thyrotropin.

Thyroid-stimulating hormone (TSH; thyrotropin) is a glycoprotein secreted from the pituitary gland. Pars distalis-derived TSH (PD-TSH) stimulates the thyroid gland to produce thyroid hormones (THs), whereas pars tuberalis-derived TSH (PT-TSH) acts on the hypothalamus to regulate seasonal physiology and behavior. However, it had not been clear how these two TSHs avoid functional crosstalk. Here, we show that this regulation is mediated by tissue-specific glycosylation. Although PT-TSH is released into the circulation, it does not stimulate the thyroid gland. PD-TSH is known to have sulfated biantennary N-glycans, and sulfated TSH is rapidly metabolized in the liver. In contrast, PT-TSH has sialylated multibranched N-glycans; in the circulation, it forms the macro-TSH complex with immunoglobulin or albumin, resulting in the loss of its bioactivity. Glycosylation is fundamental to a wide range of biological processes. This report demonstrates its involvement in preventing functional crosstalk of signaling molecules in the body.

[1]  G. Talbo,et al.  N–linked glycosylation modulates dimerization of protein disulfide isomerase family A member 2 (PDIA2) , 2013, The FEBS journal.

[2]  J. Fustin,et al.  Ancestral TSH Mechanism Signals Summer in a Photoperiodic Mammal , 2008, Current Biology.

[3]  M. Menaker,et al.  Genetic control of melatonin synthesis in the pineal gland of the mouse. , 1986, Science.

[4]  B. Weintraub,et al.  Large Molecular Weight TSH-β: The Sole Immunoactive Form of TSH-β in Certain Human Sera* , 1978 .

[5]  P. Laurberg,et al.  Narrow individual variations in serum T(4) and T(3) in normal subjects: a clue to the understanding of subclinical thyroid disease. , 2002, The Journal of clinical endocrinology and metabolism.

[6]  H. Lutz.  Naturally Occurring Antibodies (NAbs) , 2012, Advances in Experimental Medicine and Biology.

[7]  Kinji Inoue,et al.  Melatonin stimulates thyroid-stimulating hormone accumulation in the thyrotropes of the rat pars tuberalis , 2000, Histochemistry and Cell Biology.

[8]  B. Weintraub,et al.  Altered thyrotropin (TSH) carbohydrate structures in hypothalamic hypothyroidism created by paraventricular nuclear lesions are corrected by in vivo TSH-releasing hormone administration. , 1989, Endocrinology.

[9]  J. Bockmann,et al.  Daily Melatonin Injections Induce Cytological Changes in Pars Tuberalis‐Specific Cells Similar to Short Photoperiod , 1995, Journal of neuroendocrinology.

[10]  L. Hammar,et al.  Human immunodeficiency virus glycoproteins: lectin binding properties. , 1989, AIDS research and human retroviruses.

[11]  H. Ono,et al.  Involvement of thyrotropin in photoperiodic signal transduction in mice , 2008, Proceedings of the National Academy of Sciences.

[12]  B. Weintraub,et al.  Differential sulfation and sialylation of secreted mouse thyrotropin (TSH) subunits: regulation by TSH-releasing hormone. , 1986, Endocrinology.

[13]  B. Weintraub,et al.  Subunit-specific functions of N-linked oligosaccharides in human thyrotropin: role of terminal residues of alpha- and beta-subunit oligosaccharides in metabolic clearance and bioactivity. , 1995, Proceedings of the National Academy of Sciences of the United States of America.

[14]  M. Taketo,et al.  Tertiary hypothyroidism and hyperglycemia in mice with targeted disruption of the thyrotropin-releasing hormone gene. , 1997, Proceedings of the National Academy of Sciences of the United States of America.

[15]  J. Magner,et al.  β-Galactoside α-2,3-Sialyltransferase Messenger RNA Increases in Thyrotrophs of Hypothyroid Mice , 1995 .

[16]  J. Mckenzie.  The bioassay of thyrotropin in serum. , 1958, Endocrinology.

[17]  L. Moeller,et al.  Hypothyroidism in thyroid transcription factor 1 haploinsufficiency is caused by reduced expression of the thyroid-stimulating hormone receptor. , 2003, Molecular endocrinology.

[18]  B. Weintraub,et al.  Decreased receptor binding of biologically inactive thyrotropin in central hypothyroidism. Effect of treatment with thyrotropin-releasing hormone. , 1985, The New England journal of medicine.

[19]  B. Baker,et al.  Hypophyseal changes induced by thyroid deficiency and thyroxine administration as revealed by immunochemical staining. , 1971, Endocrinology.

[20]  D. Sachs,et al.  Natural antibodies against bone marrow cells of a concordant xenogeneic species. , 1991, Journal of immunology.

[21]  W. Wittkowski,et al.  Ultrastructural localization of thyrotropin (TSH)-like immunoreactivity in specific secretory cells of the hypophyseal pars tuberalis in the Djungarian hamster, Phodopus sungorus , 1989, Cell and Tissue Research.

[22]  R. Maciel,et al.  Valores inesperadamente elevados de TSH: a presença de formas de alto peso molecular ("macro TSH") deve ser investigada , 2006 .

[23]  J. Shiloach,et al.  Purification and characterization of recombinant human thyrotropin (TSH) isoforms produced by Chinese hamster ovary cells: the role of sialylation and sulfation in TSH bioactivity. , 1993, Endocrinology.

[24]  U. Wollert,et al.  Human serum albumin as a 'silent receptor' for drugs and endogenous substances. , 1979, Pharmacology.

[25]  J. Bockmann,et al.  Thyrotropin Expression in Hypophyseal Pars Tuberalis-Specific Cells is 3,5,3'-Triiodothyronine, Thyrotropin-Releasing Hormone, and Pit-1 Independent. , 1997, Endocrinology.

[26]  T. Yamamura,et al.  Light-induced hormone conversion of T4 to T3 regulates photoperiodic response of gonads in birds , 2003, Nature.

[27]  R. Weiss,et al.  Improved radioimmunoassay for measurement of mouse thyrotropin in serum: strain differences in thyrotropin concentration and thyrotroph sensitivity to thyroid hormone. , 1999, Thyroid : official journal of the American Thyroid Association.

[28]  C. Jenkin,et al.  Isolation of pure IgG1, IgG2a and IgG2b immunoglobulins from mouse serum using protein A-sepharose. , 1978, Immunochemistry.

[29]  W. Wittkowski,et al.  Photoperiod-dependent changes in TSH-like immunoreactivity of cells in the hypophysial pars tuberalis of the Djungarian hamster, Phodopus sungorus , 2004, Cell and Tissue Research.

[30]  H. Ueda,et al.  Thyrotrophin in the pars tuberalis triggers photoperiodic response , 2008, Nature.

[31]  C. Strott.  Sulfonation and molecular action. , 2002, Endocrine reviews.

[32]  T. Klug,et al.  Evidence for a large thyrotropin and its accumulation during aging in rats. , 1977, Biochemical and biophysical research communications.

[33]  H. Korf,et al.  Melatonin Transmits Photoperiodic Signals through the MT1 Melatonin Receptor , 2009, The Journal of Neuroscience.

[34]  Robert M. Graham,et al.  Transglutaminases: crosslinking enzymes with pleiotropic functions , 2003, Nature Reviews Molecular Cell Biology.

[35]  Mitsuhiro Tada,et al.  BlotGlycoABC™, an Integrated Glycoblotting Technique for Rapid and Large Scale Clinical Glycomics *S , 2008, Molecular & Cellular Proteomics.

[36]  P. Pévet,et al.  The mt1 Melatonin Receptor and RORβ Receptor Are Co-localized in Specific TSH-immunoreactive Cells in the Pars Tuberalis of the Rat Pituitary , 2002, The journal of histochemistry and cytochemistry : official journal of the Histochemistry Society.

[37]  D. Harvey,et al.  Extension of the in-gel release method for structural analysis of neutral and sialylated N-linked glycans to the analysis of sulfated glycans: application to the glycans from bovine thyroid-stimulating hormone. , 2001, Analytical biochemistry.

[38]  J. Bockmann,et al.  Cell and molecular biology of the pars tuberalis of the pituitary. , 1999, International review of cytology.

[39]  B. Weintraub,et al.  Alterations in the sialylation and sulfation of secreted mouse thyrotropin in primary hypothyroidism. , 1989, Biochemical and biophysical research communications.

[40]  J. Baenziger,et al.  Pituitary glycoprotein hormone oligosaccharides: structure, synthesis and function of the asparagine-linked oligosaccharides on lutropin, follitropin and thyrotropin. , 1988, Biochimica et biophysica acta.

[41]  M. Odawara,et al.  Falsely elevated thyroid-stimulating hormone (TSH) level due to macro-TSH. , 2009, Endocrine journal.

[42]  N. Rose,et al.  Mouse thyroid primary culture. , 1999, Biochemical and biophysical research communications.

[43]  H. Koistinen,et al.  Glycodelin in reproductive endocrinology and hormone-related cancer. , 2008, European journal of endocrinology.

[44]  B. Weintraub,et al.  Thyroid-stimulating hormone and thyroid-stimulating hormone receptor structure-function relationships. , 2002, Physiological reviews.

[45]  P. Scriba,et al.  High molecular thyrotrophin ("big"-TSH) from human pituitaries: preparation and partial characterization. , 1977, Acta endocrinologica.

[46]  J. Magner,et al.  Thyroid-stimulating hormone: biosynthesis, cell biology, and bioactivity. , 1990, Endocrine reviews.

[47]  T. Yoshimura,et al.  Localization of circadian clock protein BMAL1 in the photoperiodic signal transduction machinery in Japanese quail , 2009, The Journal of comparative neurology.

[48]  B. Weintraub,et al.  Increased high-molecular-weight thyrotropin with impaired biologic activity in a euthyroid man. , 1981, The New England journal of medicine.

[49]  T. Irimura,et al.  Molecular Cloning and Characterization of UDP-GlcNAc:Lactosylceramide β1,3-N-Acetylglucosaminyltransferase (β3Gn-T5), an Essential Enzyme for the Expression of HNK-1 and Lewis X Epitopes on Glycolipids* , 2001, The Journal of Biological Chemistry.

[50]  J. Pierce,et al.  Glycoprotein hormones: structure and function. , 1981, Annual review of biochemistry.

[51]  R. Gainetdinov,et al.  Dopamine turnover in the mediobasal hypothalamus in rat fetuses , 1999, Neuroscience.

[52]  P. Beck‐Peccoz,et al.  Changes in the degree of sialylation of carbohydrate chains modify the biological properties of circulating thyrotropin isoforms in various physiological and pathological states. , 1998, The Journal of clinical endocrinology and metabolism.

[53]  K. Wakabayashi,et al.  Changes in the multiple components of rat pituitary TSH and TSH beta subunit following thyroidectomy. , 1984, Acta endocrinologica.

[54]  H. Oda,et al.  Effects of polychlorinated biphenyls on cholesterol and ascorbic acid metabolism in primary cultured rat hepatocytes. , 1991, Biochemical pharmacology.

[55]  R. Reiter.  The pineal and its hormones in the control of reproduction in mammals. , 1980, Endocrine reviews.

[56]  M. Parmentier,et al.  Stable expression of the human TSH receptor in CHO cells and characterization of differentially expressing clones. , 1990, Biochemical and biophysical research communications.

[57]  K. Zou,et al.  Novel role of presenilins in maturation and transport of integrin beta 1. , 2008, Biochemistry.

[58]  P. Sluss,et al.  Serum half-life of pituitary gonadotropins is decreased by sulfonation and increased by sialylation in women. , 2009, The Journal of clinical endocrinology and metabolism.