Type II iodothyronine deiodinase (iodothyronine 5'-deiodinase, iodothyronine 5'-monodeiodinase) is an enzyme that in humans is encoded by the DIO2gene.[5][6][7]
The protein encoded by this gene belongs to the iodothyronine deiodinase family. It activates thyroid hormone by converting the prohormonethyroxine (T4) by outer ring deiodination (ORD) to bioactive 3,3',5-triiodothyronine (T3). It is highly expressed in the thyroid, and may contribute significantly to the relative increase in thyroidal T3 production in patients with Graves' disease and thyroid adenomas. This protein contains selenocysteine (Sec) residues encoded by the UGA codon, which normally signals translation termination. The 3' UTR of Sec-containing genes have a common stem-loop structure, the Sec insertion sequence (SECIS), which is necessary for the recognition of UGA as a Sec codon rather than as a stop signal. Alternative splicing results in multiple transcript variants encoding different isoforms.[7]
^Araki O, Murakami M, Morimura T, Kamiya Y, Hosoi Y, Kato Y, Mori M (Jun 1999). "Assignment of type II iodothyronine deiodinase gene (DIO2) to human chromosome band 14q24.2→q24.3 by in situ hybridization". Cytogenet Cell Genet. 84 (1–2): 73–74. doi:10.1159/000015218. PMID10343107. S2CID19715942.
Ohba K, Yoshioka T, Muraki T (2001). "Identification of two novel splicing variants of human type II iodothyronine deiodinase mRNA". Mol. Cell. Endocrinol. 172 (1–2): 169–175. doi:10.1016/S0303-7207(00)00368-3. PMID11165050. S2CID19110385.
Imai Y, Toyoda N, Maeda A, et al. (2002). "Type 2 iodothyronine deiodinase expression is upregulated by the protein kinase A-dependent pathway and is downregulated by the protein kinase C-dependent pathway in cultured human thyroid cells". Thyroid. 11 (10): 899–907. doi:10.1089/105072501753210957. PMID11716036.
Molnár I, Balázs C, Szegedi G, Sipka S (2002). "Inhibition of type 2,5'-deiodinase by tumor necrosis factor alpha, interleukin-6 and interferon gamma in human thyroid tissue". Immunol. Lett. 80 (1): 3–7. doi:10.1016/S0165-2478(01)00301-7. PMID11716958.
Ambroziak M, Pachucki J, Chojnowski K, et al. (2003). "Pax-8 expression correlates with type II 5' deiodinase expression in thyroids from patients with Graves' disease". Thyroid. 13 (2): 141–148. doi:10.1089/105072503321319440. PMID12699588.