Open AccessFunctional Characteristics of a Variant Thyrotropin Receptor
Author(s) -
Tonacchera Massimo,
Cetani Filomena,
Costagliola Sabine,
Sande Jacqueline,
Refetoff Samuel,
Vassart Gilbert
Publication year - 1996
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1996.0490z.x
Subject(s) - thyrotropin receptor , receptor , endocrinology , medicine , biology , computational biology , graves' disease , thyroid
A claim has been made that a variant of the human thyrotropin receptor in which Pro52 is replaced by Thr([Thr52]thyrotropinreceptor) is associated with autoimmune thyroid diseases and displays increased responsiveness to thyrotropin. We have analysed the functional characteristics of this variant receptor. Equivalent numbers of of the wild type and of the variant thyrotropin receptor, measured both by 125 I‐thyrotropin binding and by flow cytofluorimetry, were transiently expressed in COS‐7 cells. Under these conditions, the two receptors showed the same degree of constitutive activity for the cAMP pathway, the same affinity for bovine thyrotropin, and a virtually identical responsiveness to bovine thyrotropin for activation of both the cAMP and inositol‐phosphate regulatory pathways. Our results show that the [Thr52]thyrotropin receptor variant of the human thyrotropin receptor, which is present in the 12% of the population, does not affect receptor function and represents most likely a simple polymorphism.