Oxygen sensing by the prolyl-4-hydroxylase PHD2 within the nuclear compartment and the influence of compartmentalisation on HIF-1 signalling.
Hypoxia-inducible factors (HIFs) regulate more than 200 genes involved in cellular adaptation to reduced oxygen availability. HIFs are heterodimeric transcription factors that consist of one of three HIF-α subunits and a HIF-β subunit. Under normoxic conditions the HIF-α subunit is hydroxylated by members of a family of prolyl-4-hydroxylase domain (PHD) ... proteins, PHD1, PHD2 and PHD3, resulting in recognition by von-Hippel-Lindau protein, ubiquitylation and proteasomal degradation. It has been suggested that PHD2 is the key regulator of HIF-1α stability in vivo. Previous studies on the intracellular distribution of PHD2 have provided evidence for a predominant cytoplasmic localisation but also nuclear activity of PHD2. Here, we investigated functional nuclear transport signals in PHD2 and identified amino acids 196-205 as having a crucial role in nuclear import, whereas amino acids 6-20 are important for nuclear export. Fluorescence resonance energy transfer (FRET) showed that an interaction between PHD2 and HIF-1α occurs in both the nuclear and cytoplasmic compartments. However, a PHD2 mutant that is restricted to the cytoplasm does not interact with HIF-1α and shows less prolyl hydroxylase activity for its target HIF-1α than wild-type PHD2 located in the nucleus. Here, we present a new model by which PHD2-mediated hydroxylation of HIF-1α predominantly occurs in the cell nucleus and is dependent on very dynamic subcellular trafficking of PHD2.
Mesh Terms:
Active Transport, Cell Nucleus, Cell Line, Tumor, Cell Nucleus, Gene Expression, Gene Expression Regulation, Genes, Reporter, Green Fluorescent Proteins, HEK293 Cells, Humans, Hydroxylation, Hypoxia-Inducible Factor 1, alpha Subunit, Hypoxia-Inducible Factor-Proline Dioxygenases, Luciferases, Firefly, Microscopy, Fluorescence, Nuclear Localization Signals, Oxygen, Procollagen-Proline Dioxygenase, Protein Processing, Post-Translational, Recombinant Fusion Proteins, Sequence Deletion, Signal Transduction, Transcription, Genetic
Active Transport, Cell Nucleus, Cell Line, Tumor, Cell Nucleus, Gene Expression, Gene Expression Regulation, Genes, Reporter, Green Fluorescent Proteins, HEK293 Cells, Humans, Hydroxylation, Hypoxia-Inducible Factor 1, alpha Subunit, Hypoxia-Inducible Factor-Proline Dioxygenases, Luciferases, Firefly, Microscopy, Fluorescence, Nuclear Localization Signals, Oxygen, Procollagen-Proline Dioxygenase, Protein Processing, Post-Translational, Recombinant Fusion Proteins, Sequence Deletion, Signal Transduction, Transcription, Genetic
J. Cell. Sci.
Date: Nov. 01, 2012
PubMed ID: 22946054
View in: Pubmed Google Scholar
Download Curated Data For This Publication
213156
Switch View:
- Interactions 1