title: Phospholipase D1 protein coordinates dynamic assembly of HIF-1α-PHD-VHL to regulate HIF-1α stability.
abstract: Hypoxia-inducible factor-1α (HIF-1α) is a master transcriptional regulator of cellular response to hypoxia. In normoxia, HIF-1α is degraded through the prolyl hydroxylase (PHD) and von Hippel-Lindau (VHL) ubiquitination pathway. However, it is unknown whether PHD and VHL exert their enzymatic activities on HIF-1α separately or as a multiprotein complex. Here, we show that phospholipase D1 (PLD1) protein itself acts as a molecular platform, interacting directly with HIF-1α, PHD, and VHL, thereby dynamically assembling a multiprotein complex that mediates efficient degradation of HIF-1α in an O2-dependent manner. PLD1 depletion prevents degradation of HIF-1α; however, overall, PLD1 activity is predominantly involved in the upregulation of HIF-1α through increased translation, despite negative regulation of HIF-1α stability by PLD1 protein itself, suggesting dual roles of PLD1 in the regulation of HIF-1α. Disruption of the interactions of PLD1 with the proteins might be involved in hypoxic stabilization of HIF-1α. Interestingly, the pleckstrin homology domain interacting with these proteins promoted degradation of HIF-1α independent of oxygen concentration and suppressed tumor progression. These observations define a novel function of PLD1 as a previously unrecognized HIF-1α regulator.
authors.affiliation: Department of Molecular Biology, Pusan National University, Busan, Republic of Korea.
authors.forename: Mi Hee
authors.initials: MH
authors.lastname: Park
authors.affiliation: Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, Republic of Korea. Translational Research Center for Protein Function Control, Yonsei University, Seoul, Republic of Korea.
authors.forename: Kang-Yell
authors.initials: KY
authors.lastname: Choi
authors.affiliation: College of Pharmacy, Pusan National University, Busan, Republic of Korea.
authors.forename: Yunjin
authors.initials: Y
authors.lastname: Jung
authors.affiliation: Department of Molecular Biology, Pusan National University, Busan, Republic of Korea. Translational Research Center for Protein Function Control, Yonsei University, Seoul, Republic of Korea.
authors.forename: Do Sik
authors.initials: do S
authors.lastname: Min
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D064593:Heterografts; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism*; D015151:Immunoblotting; D047468:Immunoprecipitation; D051379:Mice; D008807:Mice, Inbred BALB C; D046912:Multiprotein Complexes / Q000378:metabolism*; D010739:Phospholipase D / Q000378:metabolism*; D064828:Prolyl Hydroxylases / Q000378:metabolism*; D055550:Protein Stability; D051794:Von Hippel-Lindau Tumor Suppressor Protein / Q000378:metabolism*
chemical_list: C497442:HIF1A protein, human; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D046912:Multiprotein Complexes; D064828:Prolyl Hydroxylases; D051794:Von Hippel-Lindau Tumor Suppressor Protein; D010739:Phospholipase D; C106801:phospholipase D1; C497446:VHL protein, human