Article

Chin, K.-T. et al. The liver-enriched transcription factor CREB-H is a growth suppressor protein underexpressed in hepatocellular carcinoma. Nucl. Acids Res. 33, 1859-1873

Department of Biochemistry, University of Hong Kong Hong Kong, China.
Nucleic Acids Research (Impact Factor: 9.11). 02/2005; 33(6):1859-73. DOI: 10.1093/nar/gki332
Source: PubMed

ABSTRACT

We have previously characterized transcription factor LZIP to be a growth suppressor targeted by hepatitis C virus oncoprotein.
In search of proteins closely related to LZIP, we have identified a liver-enriched transcription factor CREB-H. LZIP and CREB-H
represent a new subfamily of bZIP factors. CREB-H activates transcription by binding to cAMP responsive element, box B, and
ATF6-binding element. Interestingly, CREB-H has a putative transmembrane (TM) domain and it localizes ambiently to the endoplasmic
reticulum. Proteolytic cleavage that removes the TM domain leads to nuclear translocation and activation of CREB-H. CREB-H
activates the promoter of hepatic gluconeogenic enzyme phosphoenolpyruvate carboxykinase. This activation can be further stimulated
by cAMP and protein kinase A. CREB-H transcript is exclusively abundant in adult liver. In contrast, the expression of CREB-H
mRNA is aberrantly reduced in hepatoma tissues and cells. The enforced expression of CREB-H suppresses the proliferation of
cultured hepatoma cells. Taken together, our findings suggest that the liver-enriched bZIP transcription factor CREB-H is
a growth suppressor that plays a role in hepatic physiology and pathology.

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