Recombinant Human Thyroxine 5-deiodinase (DIO3), Truncated

Uniprot Id

P55073

Target Species

Human

Target Name

DIO3

Target Full Name

Thyroxine 5-deiodinase

Target Function

Responsible for the deiodination of T4 (3,5,3',5'-tetraiodothyronine) into RT3 (3,3',5'-triiodothyronine) and of T3 (3,5,3'-triiodothyronine) into T2 (3,3'-diiodothyronine). RT3 and T2 are inactive metabolites. May play a role in preventing premature exposure of developing fetal tissues to adult levels of thyroid hormones. Can regulate circulating fetal thyroid hormone concentrations throughout gestation. Essential role for regulation of thyroid hormone inactivation during embryological development.

Target Subcellular Location

Cell membrane; Single-pass type II membrane protein. Endosome membrane; Single-pass type II membrane protein.

Target Protein Families

Iodothyronine deiodinase family

Target Tissue Specificity

Expressed in placenta and several fetal tissues.

Target Synonyms

5DIII; D3; Deiodinase iodothyronine type 3; Deiodinase iodothyronine type III; Dio 3; Dio3; DIOIII; IOD3_HUMAN; Iodothyronine deiodinase placental type; MGC124117; MGC124118; Thyroxine deiodinase type III ; Thyroxine deiodinase type III (selenoprotein); TXDI3; Type 3 DI; Type 3 iodothyronine selenodeiodinase; Type III 5' deiodinase; Type III iodothyronine deiodinase; Type-III 5''-deiodinase

Target Background

The protein encoded by this intronless gene belongs to the iodothyronine deiodinase family. It catalyzes the inactivation of thyroid hormone by inner ring deiodination of the prohormone thyroxine (T4) and the bioactive hormone 3, 3', 5-triiodothyronine (T3) to inactive metabolites, 3, 3', 5'-triiodothyronine (RT3) and 3, 3'-diiodothyronine (T2), respectively. This enzyme is highly expressed in pregnant uterus, placenta, fetal and neonatal tissues, and thought to prevent premature exposure of developing fetal tissues to adult levels of thyroid hormones. It regulates circulating fetal thyroid hormone concentrations, and thus plays a critical role in mammalian development. Knockout mice lacking this gene exhibit abnormalities related to development and reproduction, and increased activity of this enzyme in infants with hemangiomas causes severe hypothyroidism. This protein is a selenoprotein, containing the rare selenocysteine (Sec) amino acid at its active site. Sec is encoded by the UGA codon, which normally signals translation termination. The 3' UTRs of selenoprotein mRNAs contain a conserved stem-loop structure, designated the Sec insertion sequence (SECIS) element, that is necessary for the recognition of UGA as a Sec codon rather than as a stop signal.