Protein kinase Akt/PKB phosphorylates heme oxygenase-1 in vitro and in vivo.
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 32P-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 Kd 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.
Salinas
Marta
M
Instituto de Investigaciones Biomedicas A. Sols UAM-CSIC and Departamento de Bioquímica, Facultad de Medicina, Universidad Autónoma de Madrid, Arzobispo Morcillo 4, Madrid 28029, Spain.
Wang
Jinling
J
Rosa de Sagarra
María
M
Martín
Daniel
D
Rojo
Ana I
AI
Martin-Perez
Jorge
J
Ortiz de Montellano
Paul R
PR
Cuadrado
Antonio
A
D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D016384:Consensus Sequence; D004789:Enzyme Activation; D031541:Fluorescence Resonance Energy Transfer; D015971:Gene Expression Regulation, Enzymologic; D006419:Heme Oxygenase (Decyclizing) / Q000235:genetics / Q000378:metabolism*; D051547:Heme Oxygenase-1; D006801:Humans; D008565:Membrane Proteins; D051379:Mice; D008969:Molecular Sequence Data; D041681:NIH 3T3 Cells; D010766:Phosphorylation; D017354:Point Mutation; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt; D051381:Rats; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D015290:Second Messenger Systems / Q000502:physiology*; D016415:Sequence Alignment
D008565:Membrane Proteins; D011518:Proto-Oncogene Proteins; D011994:Recombinant Proteins; C496541:HMOX1 protein, human; D006419:Heme Oxygenase (Decyclizing); D051547:Heme Oxygenase-1; C496542:Hmox1 protein, mouse; C494918:AKT1 protein, human; C494920:Akt1 protein, rat; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt