Arrest-defective-1 protein, an acetyltransferase, does not alter stability of hypoxia-inducible factor (HIF)-1alpha and is not induced by hypoxia or HIF.
The hypoxia-inducible factor (HIF) is a key player in a transcriptional pathway that controls the hypoxic response of mammalian cells. Post-translational modification of the alpha subunit of HIF determines its half-life and activity. Among the multiple reported modifications, acetylation, by an acetyltransferase termed arrest-defective-1 protein (ARD1), has been reported to decrease HIF-1alpha stability and therefore impact on hypoxic gene expression. In contrast, we report that both overexpression and silencing of ARD1 had no impact on the stability of HIF-1alpha or -2alpha and that cells silenced for ARD1 maintained hypoxic nuclear localization of HIF-1alpha. In addition, we show that the ARD1 mRNA and protein levels are not regulated by hypoxia in several human tumor cell lines, including cervical adenocarcinoma HeLa cells, fibrosarcoma HT1080 cells, adenovirus-transformed human kidney HEK293 cells, and human breast cancer MCF-7 cells. Using two model systems ((a) wild-type and HIF-1alpha-null mouse embryo fibroblasts and (b) HeLa cells silenced for HIF-1alpha or -2alpha by RNA interference), we demonstrate that the level of expression of the ARD1 protein is independent of HIF-1alpha and -2alpha. We also demonstrate that ARD1 is a stable, predominantly cytoplasmic protein expressed in a broad range of tissues, tumor cell lines, and endothelial cells. Taken together, our findings demonstrate that ARD1 has limited, if any, impact on the HIF signaling pathway.
Bilton
Rebecca
R
Institute of Signaling, Developmental Biology and Cancer Research, CNRS UMR 6543, Centre A. Lacassagne, 33 Avenue Valombrose, Nice 06189, France.
Mazure
Nathalie
N
Trottier
Eric
E
Hattab
Maurice
M
Déry
Marc-André
MA
Richard
Darren E
DE
Pouysségur
Jacques
J
Brahimi-Horn
M Christiane
MC
D000123:Acetyltransferases / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins; D045744:Cell Line, Tumor; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D005786:Gene Expression Regulation; D020868:Gene Silencing; D006801:Humans; D000860:Hypoxia; D051793:Hypoxia-Inducible Factor 1; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D051379:Mice; D018345:Mice, Knockout; D063209:N-Terminal Acetyltransferase A; D063213:N-Terminal Acetyltransferase E; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D034622:RNA Interference; D020871:RNA Stability; D015398:Signal Transduction / Q000502:physiology; D014018:Tissue Distribution; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D000099162:Endothelial PAS Domain-Containing Protein 1
D000123:Acetyltransferases; D051792:Basic Helix-Loop-Helix Proteins; D004268:DNA-Binding Proteins; D051793:Hypoxia-Inducible Factor 1; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D063209:N-Terminal Acetyltransferase A; D063213:N-Terminal Acetyltransferase E; D009687:Nuclear Proteins; D014157:Transcription Factors; D000099162:Endothelial PAS Domain-Containing Protein 1; C497442:HIF1A protein, human; C497443:Hif1a protein, mouse; C504824:NAA10 protein, human