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PSMA7, a subunit of proteasome, interacts with heme oxygenase‐2
Author(s) -
Yongzhao Zhang,
Kazumichi Furuyama,
Yuanying Ding,
Shigeki Shibahara,
Zhang Yongzhao,
Furuyama Kazumichi,
Ding Yuanying,
Shibahara Shigeki
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.6.lb36
Subject(s) - heme oxygenase , proteasome , protein subunit , chemistry , heme , microbiology and biotechnology , biology , biochemistry , gene , enzyme
Heme Oxygenase‐2 (HO‐2) is an essential enzyme in heme metabolism, and has been reported involved in oxygen sensing. Down‐regulation of HO‐2 has been suggested as an important mechanism in the maintenance of cellular heme homeostasis under certain physiological conditions. To gain insight into the mechanism that regulates HO‐2 expression, we carried out a yeast two‐hybrid analysis using HO‐2 as a bait to screen from a human bone marrow cDNA library. We identified PSMA7 (alpha 7 subunit of the 20S proteasome) as a HO‐2 interacting protein. This interaction was also confirmed by co‐immunoprecipitation in COS7 cells. In addition, analysis of several HO‐2 deletion mutants indicated that the region contains an α‐helix domain (residues 30–63) is required for its interaction with PSMA7. Furthermore, we found that transiently expressed PSMA7 decreases the expression level of endogenous HO‐2. These results indicate that PSMA7 interacts with HO‐2, and functions as a negative regulator of HO‐2 expression, thereby contributing to the maintenance of cellular heme contents. This research was supported by Grants‐in‐aid for Scientific Research (B) and by the 21st Century COE Program Special Research Grant from the Ministry of Education, Science, Sports, and Culture of Japan.