title: Down syndrome critical region 1 enhances the proteolytic cleavage of calcineurin.
abstract: Down syndrome critical region 1 (DSCR1), an oxidative stress-response gene, interacts with calcineurin and represses its phosphatase activity. Recently it was shown that hydrogen peroxide inactivates calcineurin by proteolytic cleavage. Based on these facts, we investigated whether oxidative stress affects DSCR1- mediated inactivation of calcineurin. We determined that overexpression of DSCR1 leads to increased proteolytic cleavage of calcineurin. Convertsely, knockdown of DSCR1 abolished calcineurin cleavage upon treatment with hydrogen peroxide. The PXIIXT motif in the COOH-terminus of DSCR1 is responsible for both binding and cleavage of calcineurin. The knockdown of overexpressed DSCR1 in DS fibroblast cells also abrogated calcineurin proteolysis by hydrogen peroxide. These results suggest that DSCR1 has the ability to inactivate calcineurin by inducing proteolytic cleavage of calcineurin upon oxidative stress.
authors.affiliation: National Research Laboratory for Metabolic Checkpoint, Department of Biomedical Sciences and Biochemistry and Molecular Biology, Cancer Research Institute, Seoul National University College of Medicine, Seoul 110-799, Korea.
authors.forename: Ji-Eun
authors.initials: JE
authors.lastname: Lee
authors.forename: Hyonchol
authors.initials: H
authors.lastname: Jang
authors.forename: Eun-Jung
authors.initials: EJ
authors.lastname: Cho
authors.forename: Hong-Duk
authors.initials: HD
authors.lastname: Youn