Thyroglobulin

Family: Thyroglobulin

Block: C

Parent Family: Non-catalytic_C

Comment

Only the C-terminal part of thyroglobulin is a member of the alpha/beta hydrolase family, here starting with the first G in cholinesterase 2206 (aa numbering in human thyroglobulin). The N-terminal part of thyroglobulin is made of three domains, labeled I to III, that encompass 10 repeats of a ca. 65 amino acid residues known as the Tg type-1 repeat PF00086 PS00484 IPR011641 IPR000716 not included in ESTHER. Thyroglobulin is the glycoprotein precursor to the thyroid hormones T3 (triiodothyronine) and T4 (tetraiodothyronine). It has a molecular mass of 660 kD, with 2 identical subunits, yet its complete hydrolysis yields only 2 to 4 molecules of T3 and T4. The protein contains a 19-amino acid signal peptide followed by 2,748 residues. Van Ommen (1987) suggested that defects in the TG gene can cause either dominant or recessive disorders depending on the nature of the defect. When the gene is absent or at least when no thyroglobulin is synthesized, the disorder is likely to be recessive, whereas the presence of an abnormal subunit leads to a dominantly inherited disorder. The explanation for this is that in a dimeric protein such as thyroglobulin, 75% of the dimers in heterozygotes will contain 1 or more abnormal subunits. This should profoundly disturb thyroglobulin metabolism, since this protein fulfills a dual storage/catalytic role as a dimer, is present in bulk quantities (100 mg Tg/g thyroid mass), and needs to be exocytosed, iodinated, endocytosed, and degraded. EnsemblClone AF230666, EnsemblContig AC079020.2.132816.152274, AF235100_2 gene chromosome 8 clone PAC 98A24 map 8q24.3. there is a small gene with only a little bit of thyroglobuline just 3' of the real gene AC069434.7.189089.192039 ENST00000254617 ENSG00000132287. Three out of five iodination sites are in the cholinesterase homologous domain 2573 (In T4), 2587 (In T4),2766 (In T3)