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.
Institute of Signaling, Developmental Biology and Cancer Research, CNRS UMR 6543, Centre A. Lacassagne, 33 Avenue Valombrose, Nice 06189, France.
Rebecca
R
Bilton
Nathalie
N
Mazure
Eric
E
Trottier
Maurice
M
Hattab
Marc-André
MA
Déry
Darren E
DE
Richard
Jacques
J
Pouysségur
M Christiane
MC
Brahimi-Horn
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