Slovenian researchers contribute to breakthrough in thyroid gland research

Ljubljana, 13 February - Slovenian researchers were a part of an international team that has made a breakthrough discovery in thyroid gland research. Together with researchers from the UK and Germany, they have determined the entire structure of human thyroglobulin, the protein precursor of thyroid hormones, for the first time.

The results of the study into the protein that is essential for the growth and development of thyroid hormones will have a significant impact on the treatment of thyroid gland disorders, the Jožef Stefan Institute (IJS) said in a press release on Thursday.

Using cryo-electron microscopy, the researchers from the IJS and the Centre of Excellence for Integrated Approaches in Chemistry and Biology of Proteins, Dušan Turk, Ajda Taler-Verčič and Miha Renko, cooperated with researchers from Cambridge, Berlin and Bristol to identify the full-length structure of thyroglobulin for the first time.

The results of their study were presented in the scientific journal Nature

Thyroglobulin is the protein that is used to create the T3 and T4 hormones in the thyroid gland. The two hormones regulate energy consumption of human cells and aside from thyroglobulin they are the only molecules in the human body that contain iodine.

Iodine is thus a key element for proper development and functioning of the human organism and thyroglobulin enables its storage for periods when the body is not receiving it in sufficient quantities.

The functioning of the thyroid gland is well researched, which helps control functional disorders, but up until now it was not clear how hormones are actually created in the gland.

Human thyroglobulin is a giant molecule consisting of two chains of 2,768 and 5,536 amino acids, respectively.

The structure of thyroglobulin determined by cryo-electron microscopy has revealed that the molecule has only seven spots where hormones are created.

Each molecule is formed from two amino acids called tyrosine. The newly created hormones are extracted by enzymes, protease, through decomposition of thyroglobulin into amino acids.

The article on the full-length structure of thyroglobulin is a result of almost twenty-year work and a revolution in cryo-electron microscopy, IJS said in the press release.