Figure 1.

Ero1p regulation by reduction or oxidation of its regulatory bonds. (A) Disulfide connectivity of Ero1p and Pdi1p. In Ero1p, dark gray and light gray circles indicate catalytic and regulatory cysteines, respectively. Pdi1p has four thioredoxin domains, a, b, b′, and a′. In Pdi1p, dark gray and black circles indicate catalytic and structural cysteines, respectively. (B) Ero1p cycles between oxidized (ox) and reduced (red) regulatory states in vivo according to the redox environment. Cells were incubated with 0, 0.2, or 1 mM DTT for 30 min. DTT was removed by placing cells in fresh medium. (C) Ero1p regulation in vitro. 1 µM Ero1pc was incubated with 50 µM reduced Trx1.