Structural insights into thyroid hormone transporter MCT8.

ABSTRACT: Thyroid hormones (THs), including T4 (3,5,3',5'-tetraiodo-L-thyronine) and T3 (3,5,3'-triiodo-L-thyronine), play critical roles in regulating tissue development and basal metabolism. Monocarboxylate transporter 8 (MCT8) is a key player in TH transport, known for its high specificity and affinity for THs and its direct association with Allan-Herndon-Dudley syndrome (AHDS) caused by pathogenic mutations. In this study, we present the cryo-EM structures of human MCT8 bound to the substrate T3 or the inhibitor silychristin, both in an outward-open conformation at resolutions of 3.0-3.2 Å. MCT8 forms a homodimer with a lipid molecule positioned at the dimerization interface. The carboxyl group of T3 is recognized by Arg371, while its three iodine atoms interact with distinct hydrophobic cavitie

SUBMITTER: Tan J 

PROVIDER: S-EPMC11947448 | biostudies-literature | 2025 Mar

REPOSITORIES: biostudies-literature