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Protein kinase Akt/PKB phosphorylates heme oxygenase‐1 in vitro and in vivo
Author(s) -
Salinas Marta,
Wang Jinling,
Rosa de Sagarra María,
Martín Daniel,
Rojo Ana I.,
Martin-Perez Jorge,
Ortiz de Montellano Paul R.,
Cuadrado Antonio
Publication year - 2004
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2004.10.077
Subject(s) - protein kinase b , heme oxygenase , phosphorylation , akt1 , protein kinase a , biliverdin reductase , microbiology and biotechnology , phosphoprotein , chemistry , heme , biology , biochemistry , enzyme
Heme oxygenase‐1 (HO‐1) is a stress response protein that protects cells against diverse noxious stimuli. Although regulation of HO‐1 occurs mainly at the transcriptional level, its posttranslational modifications remain unexplored. We have identified a putative consensus sequence for phosphorylation by Akt/PKB of HO‐1 at Ser188. Recombinant human and rat HO‐1, but not mutant HO‐1(S188A), are phosphorylated in vitro by Akt/PKB. Isotopic 32 P‐labeling of HEK293T cells confirmed that HO‐1 is a phosphoprotein and that the basal HO‐1 phosphorylation is increased by Akt1 activation. HO‐1(S188D), a single point mutant equivalent to the phosphorylated protein, exhibited over 1.6‐fold higher activity than wild type HO‐1. Fluorescence resonance energy transfer (FRET) studies indicated that HO‐1(S188D) bound to cytochrome P450 reductase (CPR) and biliverdin reductase (BVR) with a slightly lower K d than wild‐type HO‐1. Although the changes in activity are small, this study provides the first evidence for a role of the survival kinase Akt in the regulation of HO‐1.