Sandbox Reserved 1105: Difference between revisions
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Thyroxine (T4) is the main precursor of T3 hormone (triiodothyronine). They both control physiological processes like urinary water absorption and also cell metabolism. T4 is produced by the thyroid gland. Its concentration is used to diagnose thyroid diseases <ref name= "t4">Eshar, D., Nau, M. R., & Pohlman, L. M. (2017). PLASMA THYROXINE (T4) CONCENTRATION IN ZOO-KEPT BLACK-TAILED PRAIRIE DOGS (CYNOMYS LUDOVICIANUS). Journal of Zoo and Wildlife Medicine, 48(1), 116–120. doi:10.1638/2016-0073.1 </ref>. | Thyroxine (T4) is the main precursor of T3 hormone (triiodothyronine). They both control physiological processes like urinary water absorption and also cell metabolism. T4 is produced by the thyroid gland. Its concentration determination is used to diagnose thyroid diseases <ref name= "t4">Eshar, D., Nau, M. R., & Pohlman, L. M. (2017). PLASMA THYROXINE (T4) CONCENTRATION IN ZOO-KEPT BLACK-TAILED PRAIRIE DOGS (CYNOMYS LUDOVICIANUS). Journal of Zoo and Wildlife Medicine, 48(1), 116–120. doi:10.1638/2016-0073.1 </ref>. | ||
Two hormone binding sites are located at the dimer–dimer region bind T4 with negative cooperativity. Under physiological conditions, the bound between the natural ligand and the tetramer can’t be broken down. Moreover, there is only one hormone bound per tetramer. The negative cooperativity mechanism | Two hormone binding sites are located at the dimer–dimer region bind T4 with negative cooperativity. Under physiological conditions, the bound between the natural ligand and the tetramer can’t be broken down. Moreover, there is only one hormone bound per tetramer. The negative cooperativity mechanism | ||
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Abnormal TTR levels are found in neuropathologies such as Guillain-Barré syndrome (GBS), frontotemporal dementia (FTD), amyotrophic lateral sclerosis (ALS), amd Parkinson’s disease (PD)<ref name= "Vieira" />. | Abnormal TTR levels are found in neuropathologies such as Guillain-Barré syndrome (GBS), frontotemporal dementia (FTD), amyotrophic lateral sclerosis (ALS), amd Parkinson’s disease (PD)<ref name= "Vieira" />. | ||
Additionally, there is another defect related to TTR, which is more probable and known: the formation of amyloid fibrils. It can engender several diseases such as familial amyloid polyneuropathy (FAP), familial amyloid cardiomyopathy (FAC), and senile systemic amyloidosis (SSA) also called wild-type transthyretin amyloid (WTTA or ATTR)<ref> Faria TQ, Almeida ZL, Cruz PF, Jesus CS, Castanheira P, Brito RM. A look into amyloid formation by transthyretin: aggregation pathway and a novel kinetic model. Phys Chem Chem Phys. 2015 Mar 4;17(11):7255-63. PMID:25694367 doi:http://dx.doi.org/10.1039/c4cp04549a </ref>. Another type of disease possibly engendered due to TTR amyloid fibrils is the central nervous system selective amyloidosis (CNSA) including familial oculoleptomeningeal amyloidosis characterized by an eye injury, or meningocerebrovascular amyloidosis if the eye is not affected. <ref> P.Gambetti, C. Russo. Human brain amyloidoses. Neuphrol Dial Transplant. 1998; 13 [Suppl 7] : 33-40</ref> | |||
Inappropriate TTR foldings cause amyloidosis. Indeed, aggregates formation can be explained by a destabilization of the TTR’s native conformation, namely the tetramer dissociation into an alternative folded monomeric intermediate. The final result is a protein self-assembly. A particular beta-pleated-sheet structure characterizes the proteins with amyloidogenic potential. <ref name="Klabunde" /> | Inappropriate TTR foldings cause amyloidosis. Indeed, aggregates formation can be explained by a destabilization of the TTR’s native conformation, namely the tetramer dissociation into an alternative folded monomeric intermediate. The final result is a protein self-assembly. A particular beta-pleated-sheet structure characterizes the proteins with amyloidogenic potential. <ref name="Klabunde" /> | ||
