Alternative titles; symbols
HGNC Approved Gene Symbol: GPX4
Cytogenetic location: 19p13.3 Genomic coordinates (GRCh38): 19:1,103,994-1,106,779 (from NCBI)
| Location | Phenotype |
Phenotype MIM number |
Inheritance |
Phenotype mapping key |
|---|---|---|---|---|
| 19p13.3 | Spondylometaphyseal dysplasia, Sedaghatian type | 250220 | Autosomal recessive | 3 |
GPX4 reduces phospholipid hydroperoxides within membranes and lipoproteins and acts in conjunction with alpha-tocopherol to inhibit lipid peroxidation. Lipid peroxidation is implicated in a number of pathophysiologic processes, including inflammation and atherogenesis. GPX4 is a selenoprotein whose production and activity are sensitive to selenium (Se), which is incorporated into selenoproteins as selenocysteine (summary by Sneddon et al., 2003).
Using porcine Phgpx to screen a testis cDNA library, Esworthy et al. (1994) cloned human GPX4, which they called PHGPX. The 3-prime UTR contains a selenocysteine insertion sequence (SECIS) required for insertion of selenocysteine at an opal codon (UGA). The deduced 197-amino acid protein has a calculated molecular mass of 19 kD. It has putative active-site tryptophan and glutamic acid residues that are predicted to interact with selenocysteine, and a tyrosine residue that is phosphorylated in the porcine protein.
By fractionation and immunofluorescence microscopy of resting human platelets, Januel et al. (2006) showed that GPX4 associated with membranes, cytoplasm, and mitochondria, and that GPX4 activity showed an identical distribution. Western blot analysis detected GPX4 at an apparent molecular mass of 20 to 21 kD.
Roveri et al. (1992) found that rat Gpx4 was present primarily in testis. Januel et al. (2006) stated that rat has mitochondrial and nonmitochondrial forms of Gpx4.
Borchert et al. (2003) characterized the expression of 2 major isoforms of Gpx4 in mouse tissues. One isoform, which they designated the phospholipid (phGpx) form, was expressed in many tissues. The other, designated the sperm nucleus (snGpx) isoform, was detected in mouse testis and kidney, as well as in a human embryonic kidney cell line. Subcellular fractionation and immunoelectron microscopy revealed cytosolic localization. Immunohistochemical staining of mouse kidneys showed staining for snGpx in cortical and medullary interstitial cells. Analysis of the 5-prime flanking region common to both isoforms revealed strong promoter activity. The snGpx4 promoter, which contains 334 bp of intronic sequence, suppressed the activity of the common promoter.
Toppo et al. (2008) determined that human GPX4 likely functions as a tetramer.
To overcome inefficient selenocysteine-incorporating machinery in recombinant systems, Scheerer et al. (2007) expressed recombinant human cytosolic GPX4 containing a sec46-to-cys (U46C) mutation, which retains residual catalytic activity, in E. coli. They solved the crystal structure of this molecule to 1.55-angstrom resolution. X-ray data indicated that the monomeric protein consisted of 4 alpha helices and 7 beta strands. The catalytic triad (cys46, gln81, and trp136) localized at a flat impression on the protein surface extending into a surface-exposed patch of basic amino acids (lys48, lys135, and arg152) that also contained polar thr139. Mutation analysis confirmed the functional importance of the catalytic triad. Like the wildtype enzyme, the U46C mutant exhibited a strong tendency toward polymerization, which was prevented by reductants. Site-directed mutagenesis suggested involvement of the catalytic cys46 and surface-exposed cys10 and cys66 in polymer formation. In GPX4 crystals, these residues contacted adjacent protein monomers.
Kelner and Montoya (1998) determined that the human GPX4 gene spans 2.8 kb and contains 7 exons. Analysis of the gene sequence identified a potential alternative tissue-specific first exon.
By Southern analysis of genomic DNA from human/hamster somatic cell hybrids, Chu (1994) showed that the GPX4 gene is located on chromosome 19. By fluorescence in situ hybridization, Kelner and Montoya (1998) assigned the gene to chromosome 19p13.3.
In human umbilical vein endothelial cells (HUVECs), Sneddon et al. (2003) observed a dose-dependent increase in GPX4 mRNA and protein levels with increasing Se concentration until the Se concentration reached 76 nM. GPX4 enzyme activity was optimum at an even higher Se concentration. Sneddon et al. (2003) noted that these findings contrasted with findings in other tissues and cell types, suggesting that Se regulates GPX4 in a tissue- and cell-type specific manner, possibly reflecting the relative importance of GPX4 in individual tissues. They also found that, in addition to Se, fatty acids, cytokines, and redox state regulated GPX4 expression and activity, but sometimes in different and opposing ways.
Activation of platelets by agonists such as thrombin (F2; 176930) leads to a dramatic increase in cell surface expression of several receptors, as well as changes in platelet shape, release of arachidonic acid from phospholipids, and increased level of peroxides. Using fractionated human platelets and confocal immunofluorescence microscopy, Januel et al. (2006) found that GPX4 protein and enzymatic activity redistributed from the cytosol to membranes following platelet activation. They hypothesized that mobilization of GPX4 toward membranes protects platelets against the burst of lipid hydroperoxides and limits the stage of activation.
By yeast 3-hybrid screening of a mouse testis cDNA library, followed by RNA mobility gel shift assays, Ufer et al. (2008) found that the RNA-binding protein Grsf1 (604851) bound an AGGGGA motif in the 5-prime UTR of mitochondrial Gpx4. Grsf1 upregulated Gpx4 UTR-dependent reporter gene expression, recruited mitochondrial Gpx4 mRNA to translationally active polysomes, and coimmunoprecipitated with Gpx4 mRNA. During embryonic mouse brain development, Grsf1 and mitochondrial Gpx4 were coexpressed, and knockdown of Grsf1 via small interfering RNA prevented embryonic Gpx4 expression. Compared with mock controls, Grsf1-knockdown embryos showed developmental retardation that paralleled increased apoptosis and massive lipid peroxidation. Overexpression of mitochondrial Gpx4 prevented the apoptotic changes and rescued development in Grsf1-knockdown embryos. Ufer et al. (2008) concluded that GRSF1 upregulates translation of GPX4 mRNA and that both proteins are required for embryonic brain development.
A high-mesenchymal cell state observed in human tumors and cancer cell lines has been associated with resistance to multiple treatment modalities across diverse cancer lineages. Viswanathan et al. (2017) molecularly characterized this therapy-resistant high-mesenchymal cell state in human cancer cell lines and organoids and showed that it depends on a druggable lipid-peroxidase pathway that protects against ferroptosis, a nonapoptotic form of cell death induced by the build-up of toxic lipid peroxides. Viswanathan et al. (2017) showed that this cell state is characterized by activity of enzymes that promote the synthesis of polyunsaturated lipids. These lipids are the substrates for lipid peroxidation by lipoxygenase enzymes. This lipid metabolism creates a dependency on pathways converging on the phospholipid glutathione peroxidase (GPX4), a selenocysteine-containing enzyme that dissipates lipid peroxides and thereby prevents the iron-mediated reactions of peroxides that induce ferroptotic cell death. Dependency on GPX4 was found to exist across diverse therapy-resistant states characterized by high expression of ZEB1 (189909), including epithelial-mesenchymal transition in epithelial-derived carcinomas, TGF-beta (190180)-mediated therapy resistance in melanoma, treatment-induced neuroendocrine transdifferentiation in prostate cancer, and sarcomas, which are fixed in a mesenchymal state owing to their cells of origin. Viswanathan et al. (2017) identified vulnerability to ferroptic cell death induced by inhibition of a lipid peroxidase pathway as a feature of therapy-resistant cancer cells across diverse mesenchymal cell-state contexts.
Hangauer et al. (2017) found that cancer persister cells derived from a wide range of cancers and drug treatments are dependent on the lipid hydroperoxidase GPX4 for survival, and that this dependency is acquired. Loss of GPX4 function resulted in selective persister cell ferroptotic death in vitro and prevented tumor relapse in mice.
Villette et al. (2002) examined the 3-prime UTR of the GPX4 gene in 66 healthy Scottish volunteers and identified a T-C SNP at position 718, near the predicted SECIS element. The distribution of this SNP was in Hardy-Weinberg equilibrium, with 34% CC homozygotes, 25% TT homozygotes, and 41% TC heterozygotes. Individuals of different genotypes exhibited significant differences in the levels of lymphocyte 5-lipoxygenase total products, with CC homozygotes showing 36% and 44% more products than TT homozygotes and TC heterozygotes, respectively. Villette et al. (2002) concluded that GPX4 has a regulatory role in leukotriene biosynthesis and that the 718T-C SNP has functional effects.
Spondylometaphyseal Dysplasia, Sedaghatian Type
In a deceased female infant with the Sedaghatian type of spondylometaphyseal dysplasia (SMDS; 250220), Smith et al. (2014) identified compound heterozygosity for mutations in the GPX4 gene (138322.0001 and 138322.0002). In addition, in the unaffected first-cousin Turkish parents of a deceased male infant with SMDS, previously studied by Aygun et al. (2012), they detected heterozygosity for a nonsense mutation (Y127X; 138322.0003). DNA was unavailable from the affected child.
Ran et al. (2004) stated that Gpx4 deletion in mice is embryonic lethal, and that embryonic fibroblasts from Gpx4 +/- mice exhibit increased lipid peroxidation, more cell death after exposure to oxidizing agents, and growth retardation under high oxygen levels. They found that expression of human GPX4 rescued the lethal phenotype of Gpx4 -/- mice. Transgenic mice overexpressing human GPX4 showed reduced oxidative injury after oxidative stress.
In a deceased female infant with the Sedaghatian type of spondylometaphyseal dysplasia (SMDS; 250220), Smith et al. (2014) identified compound heterozygosity for 2 mutations in the GPX4 gene: the first was a G-to-A transition in intron 4 (c.587+5G-A), inherited from her unaffected mother, and the second was a de novo 5-bp deletion in intron 4 (c.588-8_588-4del). Functional analysis using a minigene system in HEK cells demonstrated that the first mutation causes splicing out of part of exon 4, whereas the deletion causes skipping of exon 5; both mutations result in a frameshift predicted to cause premature termination of the protein.
For discussion of the 5-bp deletion in the GPX4 gene (c.588-8_588-4del) that was found in compound heterozygous state in a deceased female infant with the Sedaghatian type of spondylometaphyseal dysplasia (SMDS; 250220) by Smith et al. (2014), see 138322.0001.
In the unaffected first-cousin Turkish parents of a male infant with the Sedaghatian type of spondylometaphyseal dysplasia (SMDS; 250220) who was originally reported by Aygun et al. (2012) and who died at 4 months of age due to respiratory insufficiency, Smith et al. (2014) identified heterozygosity for a c.381C-A transversion in exon 3 of the GPX4 gene, resulting in a tyr127-to-ter (Y127X) substitution. No DNA was available from the affected child.
Aygun, C., Celik, F. C., Nural, M. S., Azak, E., Kucukoduk, S., Ogur, G., Incesu, L. Simplified gyral pattern with cerebellar hypoplasia in Sedaghatian type spondylometaphyseal dysplasia: a clinical report and review of the literature. Am. J. Med. Genet. 158A: 1400-1405, 2012. [PubMed: 22529034] [Full Text: https://doi.org/10.1002/ajmg.a.35306]
Borchert, A., Savaskan, N. E., Kuhn, H. Regulation of expression of the phospholipid hydroperoxide/sperm nucleus glutathione peroxidase gene: tissue-specific expression pattern and identification of functional cis- and trans-regulatory elements. J. Biol. Chem. 278: 2571-2580, 2003. [PubMed: 12427732] [Full Text: https://doi.org/10.1074/jbc.M209064200]
Chu, F.-F. The human glutathione peroxidase genes GPX2, GPX3, and GPX4 map to chromosomes 14, 5, and 19, respectively. Cytogenet. Cell Genet. 66: 96-98, 1994. [PubMed: 8287691] [Full Text: https://doi.org/10.1159/000133675]
Esworthy, R. S., Doan, K., Doroshow, J. H., Chu, F.-F. Cloning and sequencing of the cDNA encoding a human testis phospholipid hydroperoxide glutathione peroxidase. Gene 144: 317-318, 1994. [PubMed: 8039723] [Full Text: https://doi.org/10.1016/0378-1119(94)90400-6]
Hangauer, M. J., Viswanathan, V. S., Ryan, M. J., Bole, D., Eaton, J. K., Matov, A., Galeas, J., Dhruv, H. D., Berens, M. E., Schreiber, S. L., McCormick, F., McManus, M. T. Drug-tolerant persister cancer cells are vulnerable to GPX4 inhibition. Nature 551: 247-250, 2017. [PubMed: 29088702] [Full Text: https://doi.org/10.1038/nature24297]
Januel, C., El Hentati, F.-Z., Carreras, M., Arthur, J. R., Calzada, C., Lagarde, M., Vericel, E. Phospholipid-hydroperoxide glutathione peroxidase (GPx-4) localization in resting platelets, and compartmental change during platelet activation. Biochim. Biophys. Acta 1761: 1228-1234, 2006. [PubMed: 17020817] [Full Text: https://doi.org/10.1016/j.bbalip.2006.07.015]
Kelner, M. J., Montoya, M. A. Structural organization of the human selenium-dependent phospholipid hydroperoxide glutathione peroxidase gene (GPX4): chromosomal localization to 19p13.3. Biochem. Biophys. Res. Commun. 249: 53-55, 1998. [PubMed: 9705830] [Full Text: https://doi.org/10.1006/bbrc.1998.9086]
Ran, Q., Liang, H., Gu, M., Qi, W., Walter, C. A., Roberts, L. J., II, Herman, B., Richardson, A., Van Remmen, H. Transgenic mice overexpressing glutathione peroxidase 4 are protected against oxidative stress-induced apoptosis. J. Biol. Chem. 279: 55137-55146, 2004. [PubMed: 15496407] [Full Text: https://doi.org/10.1074/jbc.M410387200]
Roveri, A., Casasco, A., Maiorino, M., Dalan, P., Calligaro, A., Ursini, F. Phospholipid hydroperoxide glutathione peroxidase of rat testis. J. Biol. Chem. 267: 6142-6146, 1992. [PubMed: 1556123]
Scheerer, P., Borchert, A., Krauss, N., Wessner, H., Gerth, C., Hohne, W., Kuhn, H. Structural basis for catalytic activity and enzyme polymerization of phospholipid hydroperoxide glutathione peroxidase-4 (GPx4). Biochemistry 46: 9041-9049, 2007. [PubMed: 17630701] [Full Text: https://doi.org/10.1021/bi700840d]
Smith, A. C., Mears, A. J., Bunker, R., Ahmed, A., MacKenzie, M., Schwartzentruber, J. A., Beaulieu, C. L., Ferretti, E., FORGE Canada Consortium, Majewski, J., Bulman, D. E., Celik, F. C., Boycott, K. M., Graham, G. E. Mutations in the enzyme glutathione peroxidase 4 cause Sedaghatian-type spondylometaphyseal dysplasia. J. Med. Genet. 51: 470-474, 2014. [PubMed: 24706940] [Full Text: https://doi.org/10.1136/jmedgenet-2013-102218]
Sneddon, A. A., Wu, H.-C., Farquharson, A., Grant, I., Arthur, J. R., Rotondo, D., Choe, S.-N., Wahle, K. W. J. Regulation of selenoprotein GPx4 expression and activity in human endothelial cells by fatty acids, cytokines and antioxidants. Atherosclerosis 171: 57-65, 2003. [PubMed: 14642406] [Full Text: https://doi.org/10.1016/j.atherosclerosis.2003.08.008]
Toppo, S., Vanin, S., Bosello, V., Tosatto, S. C. E. Evolutionary and structural insights into the multifaceted glutathione peroxidase (Gpx) superfamily. Antioxid. Redox Signal. 10: 1501-1514, 2008. [PubMed: 18498225] [Full Text: https://doi.org/10.1089/ars.2008.2057]
Ufer, C., Wang, C. C., Fahling, M., Schiebel, H., Thiele, B. J., Billett, E. E., Kuhn, H., Brochert, A. Translational regulation of glutathione peroxidase 4 expression through guanine-rich sequence-binding factor 1 is essential for embryonic brain development. Genes Dev. 22: 1838-1850, 2008. [PubMed: 18593884] [Full Text: https://doi.org/10.1101/gad.466308]
Villette, S., Kyle, J. A. M., Brown, K. M., Pickard, K., Milne, J. S., Nicol, F., Arthur, J. R., Hesketh, J. E. A novel single nucleotide polymorphism in the 3-prime untranslated region of human glutathione peroxidase 4 influences lipoxygenase metabolism. Blood Cells Molec. Dis. 29: 174-178, 2002. [PubMed: 12490284] [Full Text: https://doi.org/10.1006/bcmd.2002.0556]
Viswanathan, V. S., Ryan, M. J., Dhruv, H. D., Gill, S., Eichhoff, O. M., Seashore-Ludlow, B., Kaffenberger, S. D., Eaton, J. K., Shimada, K., Aguirre, A. J., Viswanathan, S. R., Chattopadhyay, S., and 28 others. Dependency of a therapy-resistant state of cancer cells on a lipid peroxidase pathway. Nature 547: 453-457, 2017. [PubMed: 28678785] [Full Text: https://doi.org/10.1038/nature23007]