TITLE

Induction of Heme-Binding Protein 23/Peroxiredoxin I Gene Expression by Okadaic Acid in Cultured Rat Hepatocytes

AUTHOR(S)
Immenschuh, Stephan; Iwahara, Shin-Ichiro; Schwennen, Bianca
PUB. DATE
April 2002
SOURCE
DNA & Cell Biology;Apr2002, Vol. 21 Issue 4, p347
SOURCE TYPE
Academic Journal
DOC. TYPE
Article
ABSTRACT
Heme-binding protein 23 (HBP23), also termed peroxiredoxin I (Prx I), is an antioxidant protein that is induced by various oxidative stress stimuli. HBP23/Prx I has thioredoxin-dependent peroxidase activity and noncovalently binds the prooxidant heme with high affinity. To investigate the regulatory role of cellular phosphorylation and dephosphorylation events on hepatic HBP23/Prx I gene expression, primary cultures of rat hepatocytes were treated with okadaic acid (OA) which is a specific inhibitor of the serine threonine protein phosphatases 1 and 2A. In hepatocyte cultures HBP23/Prx I was highly expressed for up to 5 days and, both protein and mRNA levels of HBP23/Prx I were induced by OA. The time kinetics of OA-dependent HBP23/Prx I mRNA upregulation were coordinate to that of heme oxygenase (HO)-1, which is the inducible isoform of the rate-limiting enzyme of heme-degradation. In contrast to HO-1, however, induction of HBP23/Prx I mRNA by OA was downregulated by dibutyryl-cAMP, and was enhanced by the specific protein kinase A inhibitors KT5720 and H-89. HBP23/Prx I induction by OA occurred on the transcriptional level as determined by studies with actinomycin D and nuclear run-off assays.
ACCESSION #
6754984

 

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