Myosin V Plays an Essential Role in the Thyroid Hormone-dependent Endocytosis of Type II Iodothyronine 5′-Deiodinase

Abstract

In astrocytes, thyroxine modulates type II iodothyronine 5-deiodinase levels by initiating the binding of the endosomes containing the enzyme to microfilaments, followed by actin-based endocytosis. Myosin V is a molecular motor thought to participate in vesicle trafficking in the brain. In this report, we developed an in vitro actin-binding assay to characterize the thyroid hormonedependent binding of endocytotic vesicles to microfilaments. Thyroxine and reverse triiodothyronine (EC 50 levels ϳ1 nM) were >100-…