Iodothyronine deiodinases: a functional and evolutionary perspective

Abstract

From an evolutionary perspective, deiodinases may be considered pivotal players in the emergence and functional diversification of both thyroidal systems (TS) and their iodinated messengers. To better understand the evolutionary pathway and the concomitant functional diversification of vertebrate deiodinases, in the present review we summarized the highlights of the available information regarding this ubiquitous enzymatic component that represents the final, common physiological link of TS. The information reviewed here suggests that deiodination of tyrosine metabolites is an ancient feature of all chordates studied to date and consequently, that it precedes the integration of the TS that characterize vertebrates. Phylogenetic analysis presented here points to D1 as the oldest vertebrate deiodinase and to D2 as the most recent deiodinase gene, a hypothesis that agrees with the notion that D2 is the most specialized and finely regulated member of the family and plays a key role in vertebrate neurogenesis. Thus, deiodinases seem to be major participants in the evolution and functional expansion of the complex regulatory network of TS found in vertebrates.

Characterization of Iodine-Related Molecular Processes in the Marine Microalga Tisochrysis lutea (Haptophyta)

“…In microalgae, some studies reported haloperoxidase activity (Moore et al, 1996;Murphy et al, 2000;Hill and Manley, 2009;Hughes and Sun, 2016), however, putative genes encoding putative iodoperoxidases have not been identified to date. Moreover, iodotyrosine deiodinases were only described in metazoan and bacteria (Phatarphekar et al, 2014;Taylor and Heyland, 2017) and iodothyronine deiodinases were restricted to metazoa and between social amoebae (Lobanov et al, 2007;Orozco et al, 2012;Singh et al, 2014). To increase the knowledge about iodine metabolism and oxidative defenses in T. lutea, the aims of this study were: (i) de novo assembly and characterization of a transcriptome for T. lutea cultured at high iodide concentrations; (ii) To quantify the expression patterns of antioxidant-and iodine-related genes during growth; (iii) To quantify the expression patterns of selected genes in response to iodide and iodate treatments (iv) To quantify the expression patterns of selected genes in response to H 2 O 2 and iodide treatments.…”

Role of Thyroid Hormones in Different Aspects of Cardiovascular System

“…All deiodinases are membrane-anchored proteins of [29][30][31][32][33] kDa that share substantial sequence homology; they catalyze and sequentially remove stereo-specific iodine atoms from T4, generating active and inactive isomers of both T3 and diiodothyronine [T2]. The deiodination of T4, T3, and other iodothyronines is an integral component of TH homeostasis [3,4]. There are three deiodinases: Type 1 [D1], localized to the plasma membrane and expressed in liver, thyroid and kidney, it catalyzes removal of inner or outer ring iodine atoms in equimolar proportions to generate T3, reverse T3 [rT3], or T2 , depending on the substrate.…”

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“…136,137 For instance, Dio 1 has been localized to the kidneys and liver of fish and mammals (as well as in the mammalian thyroid gland). 138 However, hepatic T4-ORD activity is thought to be catalyzed mostly by Dio 1 in mammals and Dio 2 in fish.…”