title: CITED2 controls the hypoxic signaling by snatching p300 from the two distinct activation domains of HIF-1α.
abstract: HIF-1α plays a central role in cellular adaptation to hypoxia, and is closely related to the pathogeneses of life-threatening disorders. HIF-1α induces the expressions of numerous hypoxia-induced genes through two transactivation domains; N-terminal TAD (NAD) and C-terminal TAD (CAD). Furthermore, p300 is known to boost CAD-dependent transactivation, and CBP/p300-interacting transactivator with an ED-rich tail 2 (CITED2) inhibits HIF-1α-driven gene expression by interfering with the interaction between CAD and p300. However, few researches have focused on the role of CITED2 in the regulation of NAD activity, and thus, we addressed this point. CITED2 was found to attenuate the hypoxic activations of NAD-dependent and CAD-dependent genes, suggesting that CITED2 negatively regulates both CAD and NAD. Immunoprecipitation analyses showed that NAD interacts with the Cystein/Histidine region (CH) 1 and CH3 domains of p300. Moreover, CH1 and CH3 both were required for NAD-dependent transactivation. Furthermore, CITED2 was found to inactivate NAD by interfering with NAD binding to CH1, but not to CH3. These results indicate that CITED2 inactivates HIF-1α by blocking p300 recruitment by both NAD and CAD. We also found that pVHL inhibits NAD activity regardless of NAD degradation by blocking the interaction between p300 and NAD. Summarizing, NAD was activated by binding to p300, and this was blocked by either CITED2 or pVHL. We propose that pVHL controls NAD during normoxia and that CITED2 controls NAD during hypoxia. Our results provide a new strategy for controlling HIF-1α.
authors.affiliation: Department of Pharmacology, Ischemic/Hypoxic Disease Institute, Seoul National University College of Medicine, Chongno-gu, Seoul, Republic of Korea.
authors.forename: Haejin
authors.initials: H
authors.lastname: Yoon
authors.forename: Ji-Hong
authors.initials: JH
authors.lastname: Lim
authors.forename: Chung-Hyun
authors.initials: CH
authors.lastname: Cho
authors.forename: L Eric
authors.initials: LE
authors.lastname: Huang
authors.forename: Jong-Wan
authors.initials: JW
authors.lastname: Park
mesh_terms: D015153:Blotting, Western; D002478:Cells, Cultured; D050881:E1A-Associated p300 Protein / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D000860:Hypoxia / Q000503:physiopathology*; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000235:genetics / Q000378:metabolism*; D007124:Immunoenzyme Techniques; D047468:Immunoprecipitation; D007668:Kidney / Q000166:cytology / Q000378:metabolism; D009369:Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D017434:Protein Structure, Tertiary; D012333:RNA, Messenger / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D012097:Repressor Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015534:Trans-Activators / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation; D020798:Two-Hybrid System Techniques; D051794:Von Hippel-Lindau Tumor Suppressor Protein / Q000235:genetics / Q000378:metabolism*
chemical_list: C486381:CITED2 protein, human; C497442:HIF1A protein, human; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D012097:Repressor Proteins; D015534:Trans-Activators; D050881:E1A-Associated p300 Protein; C494360:EP300 protein, human; D051794:Von Hippel-Lindau Tumor Suppressor Protein; C497446:VHL protein, human