School of Science, RMIT University, Bundoora, 3083 Victoria, Australia.
School of Health and Biomedical Sciences, RMIT University, Bundoora, 3083 Victoria, Australia.
Mol Cell Endocrinol. 2017 Dec 25;459:43-52. doi: 10.1016/j.mce.2017.02.038. Epub 2017 Feb 27.
Thyroid hormones (THs) are evolutionarily old hormones, having effects on metabolism in bacteria, invertebrates and vertebrates. THs bind specific distributor proteins (THDPs) to ensure their efficient distribution through the blood and cerebrospinal fluid in vertebrates. Albumin is a THDP in the blood of all studied species of vertebrates, so may be the original vertebrate THDP. However, albumin has weak affinity for THs. Transthyretin (TTR) has been identified in the blood across different lineages in adults vs juveniles. TTR has intermediate affinity for THs. Thyroxine-binding globulin has only been identified in mammals and has high affinity for THs. Of these THDPs, TTR is the only one known to be synthesised in the brain and is involved in moving THs from the blood into the cerebrospinal fluid. We analysed the rates of evolution of these three THDPs: TTR has been most highly conserved and albumin has had the highest rate of divergence.
甲状腺激素 (THs) 是一种古老的激素，对细菌、无脊椎动物和脊椎动物的新陈代谢都有影响。THs 与特定的分布蛋白 (THDPs) 结合，以确保它们在脊椎动物的血液和脑脊液中有效地分布。白蛋白是所有研究过的脊椎动物血液中的一种 THDP，因此可能是最初的脊椎动物 THDP。然而，白蛋白与 THs 的亲和力较弱。转甲状腺素蛋白 (TTR) 在不同发育阶段的成年和幼年个体的血液中都有被发现。TTR 与 THs 的亲和力处于中等水平。甲状腺素结合球蛋白仅在哺乳动物中被发现，并且与 THs 具有高亲和力。在这些 THDPs 中，TTR 是唯一已知在大脑中合成的，并且参与将 THs 从血液转移到脑脊液中。我们分析了这三种 THDP 的进化速度：TTR 被高度保守，而白蛋白的进化速度最快。
