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Hou W, Cai J, Shen P, Zhang S, Xiao S, You P, Tong Y, Li K, Qi Z, Luo H. Identification of FXYD6 as the novel biomarker for glioma based on differential expression and DNA methylation. Cancer Med 2023; 12:22170-22184. [PMID: 38093622 PMCID: PMC10757084 DOI: 10.1002/cam4.6752] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 09/15/2023] [Accepted: 11/09/2023] [Indexed: 12/31/2023] Open
Abstract
OBJECTIVE As a single-transmembrane protein of the FXYD family, FXYD6 plays different roles under physiological and pathological status, especially in the nervous system. This study aims to identify FXYD6 as a biomarker for glioma, by analyzing its expression and methylation patterns. METHODS Using TCGA and GTEx datasets, we analyzed FXYD6 expression in various tissues, confirming its levels in normal brain and different glioma grades via immunoblotting and immunostaining. FXYD6 biological functions were explored through enrichment analysis, and tumor immune infiltration was assessed using ESTIMATE and TIMER algorithms. Pearson correlation analysis probed FXYD6 associations with biological function-related genes. A glioma detection model was developed using FXYD6 methylation data from TCGA and GEO. Consistently, a FXYD6 methylation-based prognostic model was constructed for glioma via LASSO Cox regression. RESULTS FXYD6 was observed to be downregulated in GBM and implicated in a range of cellular functions, including synapse formation, cell junctions, immune checkpoint, ferroptosis, EMT, and pyroptosis. Hypermethylation of specific FXYD6 CpG sites in gliomas was identified, which could be used to build a diagnostic model. Additionally, FXYD6 methylation-based prognostic model could serve as an independent factor as well. CONCLUSIONS FXYD6 is a promising biomarker for the diagnosis and prognosis of glioma, with its methylation-based prognostic model serving as an independent factor. This highlights its potential in clinical application for glioma management.
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Affiliation(s)
- Weiliang Hou
- Department of Neurosurgery, Huashan Hospital, State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science and Institutes of Brain ScienceFudan UniversityShanghaiChina
| | - Jing Cai
- Department of Neurosurgery, Huashan Hospital, State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science and Institutes of Brain ScienceFudan UniversityShanghaiChina
| | - Pei Shen
- Department of Oral Surgery, Shanghai Ninth People's HospitalShanghai Jiao Tong University School of MedicineShanghaiChina
| | - Shuo Zhang
- Shanghai QuietD Biotechnology Co., Ltd.ShanghaiChina
| | - Siyu Xiao
- Department of Rehabilitation, Gongan HospitalHubei University of Chinese MedicineWuhanHubei ProvinceChina
| | - Pu You
- Shanghai QuietD Biotechnology Co., Ltd.ShanghaiChina
| | - Yusheng Tong
- Department of Neurosurgery, Huashan Hospital, State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science and Institutes of Brain ScienceFudan UniversityShanghaiChina
| | - Kaicheng Li
- Shanghai QuietD Biotechnology Co., Ltd.ShanghaiChina
| | - Zengxin Qi
- Department of Neurosurgery, Huashan Hospital, State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science and Institutes of Brain ScienceFudan UniversityShanghaiChina
| | - Hao Luo
- Shanghai QuietD Biotechnology Co., Ltd.ShanghaiChina
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Yap JQ, Seflova J, Sweazey R, Artigas P, Robia SL. FXYD proteins and sodium pump regulatory mechanisms. J Gen Physiol 2021; 153:211866. [PMID: 33688925 PMCID: PMC7953255 DOI: 10.1085/jgp.202012633] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Accepted: 02/03/2021] [Indexed: 12/12/2022] Open
Abstract
The sodium/potassium-ATPase (NKA) is the enzyme that establishes gradients of sodium and potassium across the plasma membrane. NKA activity is tightly regulated for different physiological contexts through interactions with single-span transmembrane peptides, the FXYD proteins. This diverse family of regulators has in common a domain containing a Phe-X-Tyr-Asp (FXYD) motif, two conserved glycines, and one serine residue. In humans, there are seven tissue-specific FXYD proteins that differentially modulate NKA kinetics as appropriate for each system, providing dynamic responsiveness to changing physiological conditions. Our understanding of how FXYD proteins contribute to homeostasis has benefitted from recent advances described in this review: biochemical and biophysical studies have provided insight into regulatory mechanisms, genetic models have uncovered remarkable complexity of FXYD function in integrated physiological systems, new posttranslational modifications have been identified, high-resolution structural studies have revealed new details of the regulatory interaction with NKA, and new clinical correlations have been uncovered. In this review, we address the structural determinants of diverse FXYD functions and the special roles of FXYDs in various physiological systems. We also discuss the possible roles of FXYDs in protein trafficking and regulation of non-NKA targets.
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Affiliation(s)
- John Q Yap
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, IL
| | - Jaroslava Seflova
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, IL
| | - Ryan Sweazey
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX
| | - Pablo Artigas
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX
| | - Seth L Robia
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, IL
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Luo H, Cai B, Pan J, Shi HX, Wang KK, Zhong YQ, Lu YJ, Bao L, Zhang X, Li KC. FXYD6 promotes thermal nociception by regulating TRPV1. Mol Pain 2021. [PMCID: PMC7887684 DOI: 10.1177/1744806921992249] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
FXYD6, an unnecessary auxiliary subunit of Na+,K+-ATPase, is expressed in the nervous system. However, its functions remain largely unclear. In the present study, we find that FXYD6 is involved in the thermal nociception. FXYD6 was mainly expressed in small-diameter DRG neurons expressing transient receptor potential channel V1 (TRPV1). In the SNS-Cre/Fxyd6F/F mice, loss of FXYD6 in these sensory neurons impaired the behavioral responses to noxious heat stimulus and intraplantar injection of capsaicin. The capsaicin-induced and TRPV1-mediated currents were decreased in the FXYD6–deficient DRG neurons. Heterologous expression of FXYD6 could increase the TRPV1 capsaicin-sensitive currents in HEK293 cells. Furthermore, we found that the negatively charged PGDEE motif in C-terminal of FXYD6 is required for the FXYD6/TRPV1 interaction and FXYD6-mediated enhancement of TRPV1. Disrupting the FXYD6/TRPV1 interaction with the TAT-PGDEE peptide could elevate the threshold of thermal nociception. Therefore, FXYD6 maintains the thermal nociception via interacting with TRPV1 channel in nociceptors.
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Affiliation(s)
- Hao Luo
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Bing Cai
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
- Institute of Brain-Intelligence Science and Technology, Zhangjiang Laboratory, Shanghai, China
| | - Jing Pan
- Institute of Brain-Intelligence Science and Technology, Zhangjiang Laboratory, Shanghai, China
| | - Hai-Xiang Shi
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
- State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Biology, Institute of Biochemistry and Cell Biology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Kai-Kai Wang
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Yan-Qing Zhong
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Ying-Jin Lu
- Institute of Brain-Intelligence Science and Technology, Zhangjiang Laboratory, Shanghai, China
| | - Lan Bao
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
- State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Biology, Institute of Biochemistry and Cell Biology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Xu Zhang
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
- Institute of Brain-Intelligence Science and Technology, Zhangjiang Laboratory, Shanghai, China
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
- Shanghai Clinical Research Center, Chinese Academy of Sciences/XuHui Central Hospital, Shanghai, China
| | - Kai-Cheng Li
- Institute of Brain-Intelligence Science and Technology, Zhangjiang Laboratory, Shanghai, China
- Shanghai Clinical Research Center, Chinese Academy of Sciences/XuHui Central Hospital, Shanghai, China
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Morciano M, Beckhaus T, Karas M, Zimmermann H, Volknandt W. The proteome of the presynaptic active zone: from docked synaptic vesicles to adhesion molecules and maxi-channels. J Neurochem 2009; 108:662-75. [PMID: 19187093 DOI: 10.1111/j.1471-4159.2008.05824.x] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The presynaptic proteome controls neurotransmitter release and the short and long term structural and functional dynamics of the nerve terminal. Using a monoclonal antibody against synaptic vesicle protein 2 we immunopurified a presynaptic compartment containing the active zone with synaptic vesicles docked to the presynaptic plasma membrane as well as elements of the presynaptic cytomatrix. Individual protein bands separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis were subjected to nanoscale-liquid chromatography electrospray ionization-tandem mass spectrometry. Combining this method with 2-dimensional benzyldimethyl-n-hexadecylammonium chloride/sodium dodecyl sulfate-polyacrylamide gel electrophoresis and matrix-assisted laser desorption ionization time of flight and immunodetection we identified 240 proteins comprising synaptic vesicle proteins, components of the presynaptic fusion and retrieval machinery, proteins involved in intracellular signal transduction, a large variety of adhesion molecules and proteins potentially involved in regulating the functional and structural dynamics of the pre-synapse. Four maxi-channels, three isoforms of voltage-dependent anion channels and the tweety homolog 1 were co-isolated with the docked synaptic vesicles. As revealed by in situ hybridization, tweety homolog 1 reveals a distinct expression pattern in the rodent brain. Our results add novel information to the proteome of the presynaptic active zone and suggest that in particular proteins potentially involved in the short and long term structural modulation of the mature presynaptic compartment deserve further detailed analysis.
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Affiliation(s)
- Marco Morciano
- Neurochemistry, Biocenter of Goethe-University, Frankfurt am Main, Germany
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Delprat B, Bibert S, Geering K. [FXYD proteins: novel regulators of Na,K-ATPase]. Med Sci (Paris) 2006; 22:633-8. [PMID: 16828040 DOI: 10.1051/medsci/20062267633] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Members of the FXYD protein family are small membrane proteins which are characterized by an FXYD motif, two conserved glycines and a serine residue. FXYD proteins show a tissue-specific distribution. Recent evidence suggests that 6 out of 7 FXYD proteins, FXYD1 (phospholemman), FXYD2 (gamma subunit of Na,K-ATPase), FXYD3 (Mat-8), FXYD4 (CHIF), FXYD5 (Ric) and FXYD7 associate with Na,K-ATPase and modulate its transport properties e.g. its Na+ and/or its K+ affinity in a distinct way. These results highlight the complex regulation of Na+ and K+ transport which is necessary to ensure proper tissue functions such as renal Na+-reabsorption, muscle contractility and neuronal excitability. Moreover, mutation of a conserved glycine residue into an arginine residue in FXYD2 has been linked to cases of human hypomagnesemia indicating that dysregulation of Na,K-ATPase by FXYD proteins may be implicated in pathophysiological states. A better characterization of this novel regulatory mechanism of Na,K-ATPase may help to better understand its role in physiological and pathophysiological conditions.
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Affiliation(s)
- Benjamin Delprat
- Département de Pharmacologie et Toxicologie, Université de Lausanne, rue du Bugnon 27, 1005 Lausanne, Suisse
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Abstract
FXYD proteins belong to a family of small-membrane proteins. Recent experimental evidence suggests that at least five of the seven members of this family, FXYD1 (phospholemman), FXYD2 (gamma-subunit of Na-K-ATPase), FXYD3 (Mat-8), FXYD4 (CHIF), and FXYD7, are auxiliary subunits of Na-K-ATPase and regulate Na-K-ATPase activity in a tissue- and isoform-specific way. These results highlight the complexity of the regulation of Na+ and K+ handling by Na-K-ATPase, which is necessary to ensure appropriate tissue functions such as renal Na+ reabsorption, muscle contractility, and neuronal excitability. Moreover, a mutation in FXYD2 has been linked to cases of human hypomagnesemia, indicating that perturbations in the regulation of Na-K-ATPase by FXYD proteins may be critically involved in pathophysiological states. A better understanding of this novel regulatory mechanism of Na-K-ATPase should help in learning more about its role in pathophysiological states. This review summarizes the present knowledge of the role of FXYD proteins in the modulation of Na-K-ATPase as well as of other proteins, their regulation, and their structure-function relationship.
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Affiliation(s)
- Käthi Geering
- Dept. of Pharmacology and Toxicology, Univ. of Lausanne, Rue du Bugnon 27, 1005 Lausanne, Switzerland.
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Kadowaki K, Sugimoto K, Yamaguchi F, Song T, Watanabe Y, Singh K, Tokuda M. Phosphohippolin expression in the rat central nervous system. ACTA ACUST UNITED AC 2004; 125:105-12. [PMID: 15193427 DOI: 10.1016/j.molbrainres.2004.03.021] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/16/2004] [Indexed: 11/18/2022]
Abstract
The FXYD family is a small single-span membrane protein family; recently, we have identified a novel member of this family from the cDNA library of the rat hippocampus and named phosphohippolin (Php) (Mol. Br. Res. vol. 86, 2001). The deduced amino acid sequence of this novel Php comprises 93 residues with a core motif of FXYD and a single transmembrane domain. This indicates that Php belongs to FXYD6 subfamily of the seven FXYD subfamilies (FXYD1-7). Php shows a 48.1% homology with rat phospholemman (FXYD1), a transmembrane family protein. In this study, polyclonal antibodies against the carboxyl-terminal sequence of rat Php were raised and purified. The spatial expression of the Php protein was in the neuronal fibers of the medial part of lateral habenula nucleus, thalamus, hypothalamus, stria terminalis, zona incerta, amygdaloid body and cingulum, olfactory bulb, hippocampus, cerebral cortex and cerebellum. A unique Php distribution was identified in the cerebellum, with a predominant expression pattern in the granule layer of lobules VI-IX of the posterior lobe. Developmental studies demonstrated that the highest level of Php expression was seen in the postnatal (PN) 3-week-old rat brain, and a significant amount of Php still existed in the adult brain. These findings suggest that Php may play an important role in the excitability of neurons in the central nervous system during postnatal development, as well as those in the adult brain.
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Affiliation(s)
- Kae Kadowaki
- Department of Cell Physiology, Faculty of Medicine, Kagawa University, 1750-1 Ikenobe, Miki-cho, 761-0793, Japan
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Schuurmans Stekhoven FMAH, Grell E, Atsma W, Flik G, Wendelaar Bonga SE. Organ-related distribution of phospholemman in the spiny dogfish Squalus acanthias. Biochem Biophys Res Commun 2003; 303:1008-11. [PMID: 12684034 DOI: 10.1016/s0006-291x(03)00472-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The distribution of phospholemman among nine different organs of the spiny dogfish (Squalus acanthias) has been determined on the basis of Western blotting of microsomal material. Only rectal gland (100%), brain (43%), heart (18%), and kidney (19%) (abundancies as percent of the concentration in rectal gland) contained the protein, but not gill and colon. The relative abundance in the brain makes this organ a preferential test system for phospholemman in fishes that lack a rectal gland like teleosts.
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Phospholemman, a single-span membrane protein, is an accessory protein of Na,K-ATPase in cerebellum and choroid plexus. J Neurosci 2003. [PMID: 12657675 DOI: 10.1523/jneurosci.23-06-02161.2003] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Phospholemman (FXYD1) is a homolog of the Na,K-ATPase gamma subunit (FXYD2), a small accessory protein that modulates ATPase activity. Here we show that phospholemman is highly expressed in selected structures in the CNS. It is most abundant in cerebellum, where it was detected in the molecular layer, in Purkinje neurons, and in axons traversing the granule cell layer. Phospholemman was particularly enriched in choroid plexus, the organ that secretes CSF in the ventricles, where it colocalized with Na,K-ATPase in the apical membrane. It was also enriched, with Na,K-ATPase, in certain tanycytes or ependymal cells of the ventricle wall. Two different experimental approaches demonstrated that phospholemman physically associated with the Na,K-ATPase in cerebellum and choroid plexus: the proteins copurified after detergent treatment and co-immunoprecipitated from solubilized crude membranes using either anti-phospholemman or anti-Na,K-ATPase antibodies. Phospholemman antibodies precipitated all three Na,K-ATPase alpha subunit isoforms (alpha1-alpha3) from cerebellum, indicating that the interaction is not specific to a particular alpha isoform and consistent with the presence of phospholemman in both neurons and glia. Antibodies against the C-terminal domain of phospholemman reduced Na,K-ATPase activity in vitro without effect on Na+ affinity. At least two other FXYD family members have been detected in the CNS, suggesting that additional complexity of sodium pump regulation will be found.
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Crowell KJ, Franzin CM, Koltay A, Lee S, Lucchese AM, Snyder BC, Marassi FM. Expression and characterization of the FXYD ion transport regulators for NMR structural studies in lipid micelles and lipid bilayers. BIOCHIMICA ET BIOPHYSICA ACTA 2003; 1645:15-21. [PMID: 12535606 PMCID: PMC2917601 DOI: 10.1016/s1570-9639(02)00473-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The proteins PLM (phospholemman), CHIF (channel inducing factor), and Mat8 (mammary tumor protein 8 kDa) are members of the FXYD family of ion transport regulatory membrane proteins. Here we describe their cloning and expression in Escherichia coli, and their purification for NMR structural studies in lipid micelles and lipid bilayers. The molecular masses of the purified recombinant FXYD proteins, determined from SDS-PAGE and from MALDI TOF mass spectrometry, reflect monomeric species. The solution NMR and CD spectra in SDS micelles show that they adopt helical conformations. The solid-state NMR spectra in lipid bilayers give the first view of their transmembrane architecture.
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Affiliation(s)
| | | | | | | | | | | | - Francesca M. Marassi
- Corresponding author. Tel.: +1-858-713-6282; fax: +1-858-713-6268, (F.M. Marassi)
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