Thioredoxin-interacting protein (Txnip), originally characterized as an inhibitor of
thioredoxin, is now known to be a critical regulator of glucose metabolism in vivo. Txnip is a
member of the α-arrestin protein family; the α-arrestins are related to the classical β-arrestins
and visual arrestins. Txnip is the only α-arrestin known to bind thioredoxin, and it is not
known whether the metabolic effects of Txnip are related to its ability to bind thioredoxin or
related to conserved α-arrestin function. Here we show that wild type Txnip and Txnip …