Novel HIF-2α interaction with Reptin52 impairs HIF-2 transcriptional activity and EPO secretion

Ioanna Maria Gkotinakou; Christina Befani; Martina Samiotaki; George Panayotou; Panagiotis Liakos

doi:10.1016/j.bbrc.2021.03.176

Novel HIF-2α interaction with Reptin52 impairs HIF-2 transcriptional activity and EPO secretion

Biochem Biophys Res Commun. 2021 Jun 11:557:143-150. doi: 10.1016/j.bbrc.2021.03.176. Epub 2021 Apr 14.

Authors

Ioanna Maria Gkotinakou¹, Christina Befani¹, Martina Samiotaki², George Panayotou², Panagiotis Liakos³

Affiliations

¹ Laboratory of Biochemistry, Faculty of Medicine, University of Thessaly, Biopolis, 41500, Larissa, Greece.
² Institute of Bioinnovation, BSRC "Alexander Fleming,", Vari, 16672, Greece.
³ Laboratory of Biochemistry, Faculty of Medicine, University of Thessaly, Biopolis, 41500, Larissa, Greece. Electronic address: pliakos@med.uth.gr.

PMID: 33865222
DOI: 10.1016/j.bbrc.2021.03.176

Abstract

Hypoxia-inducible factor 2 (HIF-2), is essential for cellular response to hypoxia and holds an important role in erythropoiesis, angiogenesis, tissue invasion and metastasis, thus, constituting an important therapeutic target. Maximal HIF-2 transcriptional activation requires HIF-2α phosphorylation by ERK1/2 that impairs its CRM1-mediated nuclear export. Herein, we reveal a novel interaction of HIF-2α with Reptin52, a multifunctional protein involved in cellular functions orchestrated both in the nucleus and the cytoplasm. HIF-2α and Reptin52 interact both in nuclear and cytoplasmic fractions, however, ERK1/2 pathway inactivation seems to favour their association in the cytoplasm. Notably, we demonstrate that Reptin52 reduces HIF-2 transcriptional activity, which results in decreased EPO secretion under hypoxia, by impairing HIF-2α stability via a non-canonical PHD-VHL-proteasome independent mechanism. This interaction represents a novel HIF-2 fine tuning mechanism that allows for distinct HIF1/2 isoforms regulation.

Keywords: EPO; HIF-2α; HIF-2α stability; Hypoxia; Reptin52.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

ATPases Associated with Diverse Cellular Activities / genetics
ATPases Associated with Diverse Cellular Activities / metabolism*
Basic Helix-Loop-Helix Transcription Factors / genetics
Basic Helix-Loop-Helix Transcription Factors / metabolism*
Carrier Proteins / genetics
Carrier Proteins / metabolism*
Cell Hypoxia
Cell Line, Tumor
Cell Nucleus / genetics
Cell Nucleus / metabolism
Chromatography, Liquid
Cytoplasm / genetics
Cytoplasm / metabolism
DNA Helicases / genetics
DNA Helicases / metabolism*
Erythropoiesis / genetics
Erythropoietin / genetics
Erythropoietin / metabolism*
Gene Expression Regulation / genetics*
Humans
MAP Kinase Signaling System / genetics*
Mitogen-Activated Protein Kinase 1 / metabolism
Mitogen-Activated Protein Kinase 3 / metabolism
Phosphorylation
Proteasome Endopeptidase Complex / metabolism
Protein Stability
RNA, Small Interfering
Real-Time Polymerase Chain Reaction
Tandem Mass Spectrometry

Substances

Basic Helix-Loop-Helix Transcription Factors
Carrier Proteins
EPO protein, human
RNA, Small Interfering
Erythropoietin
endothelial PAS domain-containing protein 1
MAPK1 protein, human
MAPK3 protein, human
Mitogen-Activated Protein Kinase 1
Mitogen-Activated Protein Kinase 3
Proteasome Endopeptidase Complex
ATPases Associated with Diverse Cellular Activities
DNA Helicases
RUVBL2 protein, human