A novel mutation of indoleamine 2,3-dioxygenase 1 causes a rapid proteasomal degradation and compromises protein function.

A novel mutation of indoleamine 2,3-dioxygenase 1 causes a rapid proteasomal degradation and compromises protein function. J Autoimmun. 2020 Jun 27;:102509 Authors: Mondanelli G, Di Battista V, Pellanera F, Mammoli A, Macchiarulo A, Gargaro M, Mavridou E, Matteucci C, Ruggeri L, Orabona C, Volpi C, Grohmann U, Mecucci C Abstract Indoleamine 2,3-dioxygenase 1 (IDO1) - the enzyme catalyzing the rate-limiting step of tryptophan catabolism along the kynurenine pathway - belongs to the class of inhibitory immune checkpoint molecules. Such regulators of the immune system are crucial for maintaining self-tolerance and thus, when properly working, preventing autoimmunity. A dysfunctional IDO1 has recently been associated with a specific single nucleotide polymorphism (SNP) and with the occurrence of autoimmune diabetes and multiple sclerosis. Many genetic alterations of IDO1 have been proposed being related with dysimmune disorders. However, the molecular and functional meaning of variations in IDO1 exomes as well as the promoter region remains a poorly explored field. In the present study, we identified a rare missense variant (rs751360195) at the IDO1 gene in a patient affected by coeliac disease, thyroiditis, and selective immunoglobulin A deficiency. Molecular and functional studies demonstrated that the substitution of lysine (K) at position 257 with a glutamic acid (E) results in an altered IDO1 protein that undergoes a rapid protein t...
Source: Journal of Autoimmunity - Category: Allergy & Immunology Authors: Tags: J Autoimmun Source Type: research