GPHN

Gene Summary

Gene:GPHN; gephyrin
Aliases: GPH, GEPH, HKPX1, GPHRYN, MOCODC
Location:14q23.3-q24.1
Summary:This gene encodes a neuronal assembly protein that anchors inhibitory neurotransmitter receptors to the postsynaptic cytoskeleton via high affinity binding to a receptor subunit domain and tubulin dimers. In nonneuronal tissues, the encoded protein is also required for molybdenum cofactor biosynthesis. Mutations in this gene may be associated with the neurological condition hyperplexia and also lead to molybdenum cofactor deficiency. Numerous alternatively spliced transcript variants encoding different isoforms have been described; however, the full-length nature of all transcript variants is not currently known. [provided by RefSeq, Jul 2008]
Databases:VEGA, OMIM, HGNC, Ensembl, GeneCard, Gene
Protein:gephyrin
Source:NCBIAccessed: 11 March, 2017

Ontology:

What does this gene/protein do?
Show (14)
Pathways:What pathways are this gene/protein implicaed in?
Show (1)

Cancer Overview

Research Indicators

Publications Per Year (1992-2017)
Graph generated 11 March 2017 using data from PubMed using criteria.

Literature Analysis

Mouse over the terms for more detail; many indicate links which you can click for dedicated pages about the topic.

  • Hemangioblastoma
  • Oncogene Fusion Proteins
  • Transcription Factors
  • Chromosome 14
  • Chromosome Aberrations
  • Cancer Gene Expression Regulation
  • Antineoplastic Agents
  • Histone-Lysine N-Methyltransferase
  • Loss of Heterozygosity
  • Chromosome 11
  • Computer Simulation
  • Oligonucleotide Array Sequence Analysis
  • Base Sequence
  • Amino Acid Sequence
  • KMT2A
  • Single Nucleotide Polymorphism
  • Tissue Array Analysis
  • FISH
  • Membrane Proteins
  • Gene Expression Profiling
  • Cloning, Molecular
  • Lung Cancer
  • Leukemia, Monocytic, Acute
  • Polymerase Chain Reaction
  • Prostate Cancer
  • Computational Biology
  • Chromosomes, Human
  • Proto-Oncogenes
  • MLL
  • DNA Copy Number Variations
  • Carrier Proteins
  • Genetic Association Studies
  • Reproducibility of Results
  • DNA-Binding Proteins
  • Translocation
  • gephyrin
  • Signal Transduction
  • MicroRNAs
  • Neoplasm Proteins
Tag cloud generated 11 March, 2017 using data from PubMed, MeSH and CancerIndex

Specific Cancers (3)

Data table showing topics related to specific cancers and associated disorders. Scope includes mutations and abnormal protein expression.

Note: list is not exhaustive. Number of papers are based on searches of PubMed (click on topic title for arbitrary criteria used).

Latest Publications: GPHN (cancer-related)

Mehrian-Shai R, Yalon M, Moshe I, et al.
Identification of genomic aberrations in hemangioblastoma by droplet digital PCR and SNP microarray highlights novel candidate genes and pathways for pathogenesis.
BMC Genomics. 2016; 17:56 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: The genetic mechanisms underlying hemangioblastoma development are still largely unknown. We used high-resolution single nucleotide polymorphism microarrays and droplet digital PCR analysis to detect copy number variations (CNVs) in total of 45 hemangioblastoma tumors.
RESULTS: We identified 94 CNVs with a median of 18 CNVs per sample. The most frequently gained regions were on chromosomes 1 (p36.32) and 7 (p11.2). These regions contain the EGFR and PRDM16 genes. Recurrent losses were located at chromosome 12 (q24.13), which includes the gene PTPN11.
CONCLUSIONS: Our findings provide the first high-resolution genome-wide view of chromosomal changes in hemangioblastoma and identify 23 candidate genes: EGFR, PRDM16, PTPN11, HOXD11, HOXD13, FLT3, PTCH, FGFR1, FOXP1, GPC3, HOXC13, HOXC11, MKL1, CHEK2, IRF4, GPHN, IKZF1, RB1, HOXA9, and micro RNA, such as hsa-mir-196a-2 for hemangioblastoma pathogenesis. Furthermore, our data implicate that cell proliferation and angiogenesis promoting pathways may be involved in the molecular pathogenesis of hemangioblastoma.

Li J, Meeks H, Feng BJ, et al.
Targeted massively parallel sequencing of a panel of putative breast cancer susceptibility genes in a large cohort of multiple-case breast and ovarian cancer families.
J Med Genet. 2016; 53(1):34-42 [PubMed] Free Access to Full Article Related Publications
INTRODUCTION: Gene panel testing for breast cancer susceptibility has become relatively cheap and accessible. However, the breast cancer risks associated with mutations in many genes included in these panels are unknown.
METHODS: We performed custom-designed targeted sequencing covering the coding exons of 17 known and putative breast cancer susceptibility genes in 660 non-BRCA1/2 women with familial breast cancer. Putative deleterious mutations were genotyped in relevant family members to assess co-segregation of each variant with disease. We used maximum likelihood models to estimate the breast cancer risks associated with mutations in each of the genes.
RESULTS: We found 31 putative deleterious mutations in 7 known breast cancer susceptibility genes (TP53, PALB2, ATM, CHEK2, CDH1, PTEN and STK11) in 45 cases, and 22 potential deleterious mutations in 31 cases in 8 other genes (BARD1, BRIP1, MRE11, NBN, RAD50, RAD51C, RAD51D and CDK4). The relevant variants were then genotyped in 558 family members. Assuming a constant relative risk of breast cancer across age groups, only variants in CDH1, CHEK2, PALB2 and TP53 showed evidence of a significantly increased risk of breast cancer, with some supportive evidence that mutations in ATM confer moderate risk.
CONCLUSIONS: Panel testing for these breast cancer families provided additional relevant clinical information for <2% of families. We demonstrated that segregation analysis has some potential to help estimate the breast cancer risks associated with mutations in breast cancer susceptibility genes, but very large case-control sequencing studies and/or larger family-based studies will be needed to define the risks more accurately.

Kluth M, Galal R, Krohn A, et al.
Prevalence of chromosomal rearrangements involving non-ETS genes in prostate cancer.
Int J Oncol. 2015; 46(4):1637-42 [PubMed] Related Publications
Prostate cancer is characterized by structural rearrangements, most frequently including translocations between androgen-dependent genes and members of the ETS family of transcription factor like TMPRSS2:ERG. In a recent whole genome sequencing study we identified 140 gene fusions that were unrelated to ETS genes in 11 prostate cancers. The aim of the present study was to estimate the prevalence of non-ETS gene fusions. We randomly selected 27 of these rearrangements and analyzed them by fluorescence in situ hybridization (FISH) in a tissue microarray format containing 500 prostate cancers. Using break-apart FISH probes for one fusion partner each, we found rearrangements of 13 (48%) of the 27 analyzed genes in 300-400 analyzable cancers per gene. Recurrent breakage, often accompanied by partial deletion of the genes, was found for NCKAP5, SH3BGR and TTC3 in 3 (0.8%) tumors each, as well as for ARNTL2 and ENOX1 in 2 (0.5%) cancers each. One rearranged tumor sample was observed for each of VCL, ZNF578, IMMP2L, SLC16A12, PANK1, GPHN, LRP1 and ZHX2. Balanced rearrangements, indicating possible gene fusion, were found for ZNF578, SH3BGR, LPR12 and ZHX2 in individual cancers only. The results of the present study confirm that rearrangements involving non-ETS genes occur in prostate cancer, but demonstrate that they are highly individual and typically non-recurrent.

Minchenko JM, Dyagil IS, Dmytrenko OO, et al.
Role of radiosensitivity and radioresistance genetic markers in hematological and cardiovascular disease in persons exposed after the Chornobyl accident.
Probl Radiac Med Radiobiol. 2013; (18):220-31 [PubMed] Related Publications
UNLABELLED: The objective was to study the immunogenetic component contribution to the formation of post-radiation effects in the long-term period after radiation exposure at the level of the human immune response as a prognostic criterion for risk assessment of radiation-associated somatic diseases. Study object was the convalescents of acute radiation syndrome (ARS) of the first grade of severity, 88 patients with a similar radiation history but with unconfirmed ARS, 73 patients being the liquidators of the Chornobyl accident consequences (LCAC) with chronic ischemic heart disease (HIHD), 65 patients LCAC without HIHD, 120 non-exposed patients with HIHD, 256 patients with oncohematological diseases and 500 healthy people - a population control.
RESULTS: Markers of risk of realization of genetic predisposition to oncohematological and cardiovascular disease in these groups were identified on the basis of study of immunological, hematological and molecular genetic disorders in relation to immunogenetic factors.
CONCLUSION: These data indicate that realization of HLA-genetic predisposition to the disease is one of the radiation associated multifactorial pathology pathways, and presence of radiosensitivity markers in pheno/genotype enhances the realization risk of pathological process under irradiation.

Agrawal M, Gadgil M
Meta analysis of gene expression changes upon treatment of A549 cells with anti-cancer drugs to identify universal responses.
Comput Biol Med. 2012; 42(11):1141-9 [PubMed] Related Publications
A meta-analysis of publicly available gene expression changes in A549 cells upon treatment with anti-cancer drugs is reported. To reduce false positives, both fold-change and significance level cutoffs were used. Simulated datasets and permutation analysis were used to guide choice of ratio cutoff. Of the genes identified, FDXR is the only gene differentially expressed in six of the seven drug treatments. Though FDXR has been reported to be differentially expressed upon treatment with 5-fluorouracil and its expression correlated to long term disease survival, to our knowledge this is a first study implicating a wide effect of anti-cancer drug treatment on FDXR expression. The other genes identified which are differentially expressed in four out of the seven drug treatments are CDKN1A and PARVB which are upregulated and MYC, HBP1, LDLR, SIM2, ALX1 and GPHN which are downregulated.

Ozawa T, Itoyama T, Sadamori N, et al.
Rapid isolation of viral integration site reveals frequent integration of HTLV-1 into expressed loci.
J Hum Genet. 2004; 49(3):154-65 [PubMed] Related Publications
Although there is tight association of the human T-cell leukemia virus type-1 (HTLV-1) with adult T-cell leukemia/lymphoma (ATLL), it has remained unresolved whether the HTLV-1 integration into the host genome has any role in the development of this disease. We isolated a total of 58 HTLV-1 integration sites using newly developed, adaptor-ligated PCR from 33 ATLL patients and five ATLL cell lines. We compared our data as well as the previously reported ones with the complete human genomic sequence for the location of its placement, structure, and expression of genes nearby the integration site. The chromosomal target for integration was selected at random, but the integration favorably occurred within the transcription units; more than 59.5% of total integration was observed within the transcriptional unit. All inserted genes by HTLV-1 integration were expressed in normal T cells. Upregulation of genes due to viral integration was found in two out of nine ATLL cases; about 4.4- and 102-fold elevated ankyrin-1 ( ANK-1) and gephyrin ( GPHN) gene expressions were observed, respectively. These data suggest that the preferential integration of HTLV-1 into an expressed locus occasionally causes deregulation of corresponding gene, which may lead to leukemogenesis of a fraction of ATLL.

Eguchi M, Eguchi-Ishimae M, Greaves M
The small oligomerization domain of gephyrin converts MLL to an oncogene.
Blood. 2004; 103(10):3876-82 [PubMed] Related Publications
The MLL (mixed lineage leukemia) gene forms chimeric fusions with a diverse set of partner genes as a consequence of chromosome translocations in leukemia. In several fusion partners, a transcriptional activation domain appears to be essential for conferring leukemogenic capacity on MLL protein. Other fusion partners, however, lack such domains. Here we show that gephyrin (GPHN), a neuronal receptor assembly protein and rare fusion partner of MLL in leukemia, has the capacity as an MLL-GPHN chimera to transform hematopoietic progenitors, despite lack of transcriptional activity. A small 15-amino acid tubulin-binding domain of GPHN is necessary and sufficient for this activity in vitro and in vivo. This domain also confers oligomerization capacity on MLL protein, suggesting that such activity may contribute critically to leukemogenesis. The transduction of MLL-GPHN into hematopoietic progenitor cells caused myeloid and lymphoid lineage leukemias in mice, suggesting that MLL-GPHN can target multipotent progenitor cells. Our results, and other recent data, provide a mechanism for oncogenic conversion of MLL by fusion partners encoding cytoplasmic proteins.

Eguchi M, Eguchi-Ishimae M, Seto M, et al.
GPHN, a novel partner gene fused to MLL in a leukemia with t(11;14)(q23;q24).
Genes Chromosomes Cancer. 2001; 32(3):212-21 [PubMed] Related Publications
We report a novel MLL-associated chromosome translocation t(11;14)(q23;q24) in a child who showed signs of acute undifferentiated leukemia 3 years after intensive chemotherapy that included the topoisomerase-II inhibitor VP 16. Screening of a cDNA library of the patient's leukemic cells showed a novel fusion transcript between MLL and the Gephyrin (GPHN) gene on 14q24. The resulting MLL-GPHN fusion gene encodes MLL AT hook motifs and a DNA methyltransferase homology domain fused to the C-terminal half of Gephyrin, including a presumed tubulin binding site and a domain homologous to the Escherichia coli molybdenum cofactor biosynthesis protein MoeA. Genomic breakpoint analysis showed potential in vitro topoisomerase-II DNA-binding sites spanning the breakpoints in both MLL and GPHN but no flanking sequences that might mediate homologous recombination. This suggests that MLL-GPHN may have been generated by VP 16/topoisomerase-II-induced DNA double-strand breaks, followed by error-prone DNA repair via non-homologous end joining. Gephyrin was originally identified as a submembraneous scaffold protein that anchors and immobilizes postsynaptic membrane neurotransmitter receptors to underlying cytoskeletal elements. It also is reported to bind to phosphatidylinositol 3,4,5-triphosphate binding proteins involved in actin dynamics and downstream signaling and interacts with ATM-related family member RAFT1. Gephyrin domains in the chimeric protein therefore could contribute novel signal sequences or might modify MLL activity by oligomerization or intracellular redistribution.

Dirnhofer S, Berger C, Hermann M, et al.
Coexpression of gonadotropic hormones and their corresponding FSH- and LH/CG-receptors in the human prostate.
Prostate. 1998; 35(3):212-20 [PubMed] Related Publications
BACKGROUND: Benign prostatic hyperplasia (BPH) affects the majority of elderly men, and prostate cancer is the most common male cancer. Prostatic growth and function are thought to be regulated by steroid hormones, primarily androgens and estrogens, but nonandrogenic hormones must also be considered. The increasing evidence of para/autocrine functions of the gonadotropic glycoprotein-hormones (GPH), their allocation to the superfamily of cystine-knot growth factors, and luteinizing hormone (LH)/chorionic gonadotropin (CG)-receptor (R) gene expression in nongonadal tissues led us to investigate intraprostatic GPH and GPH-R gene expression.
METHODS AND RESULTS: RT-PCR and subsequent Southern hybridization and/or restriction enzyme analysis of BPH and prostatic adenocarcinoma demonstrated that all three human (h) gonadotropic hormones, i.e., follicle-stimulating hormone (FSH), LH, and CG, as well as the corresponding FSH-R and LH/CG-R, are transcribed intraprostatically. Significant amounts of the alpha and beta subunits of hCG were secreted by short-term primary cultures of human BPH tissues, as detected by highly sensitive and specific time-resolved immunofluorometric assays (IFMAs).
CONCLUSIONS: Our data suggest that prostatic- and pituitary-derived GPH act directly on the prostatic gland, particularly FSH via the FSH-R, thereby possibly modulating locally acting key hormones and growth factors involved in BPH development.

Ikuyama S, Ohe K, Sakai Y, et al.
Follicle stimulating hormone-beta subunit gene is expressed in parallel with a transcription factor Ad4BP/SF-1 in human pituitary adenomas.
Clin Endocrinol (Oxf). 1996; 45(2):187-93 [PubMed] Related Publications
OBJECTIVES: A transcription factor Ad4BP/SF-1 is implicated in the differentiation of gonadotrophs in the pituitary gland, but it is not known whether human pituitary cells express this factor. The present study aimed to disclose (1) whether human pituitary adenomas express Ad4BP/SF-1, and (2) if this is the case, what kinds of adenoma express the factor.
MATERIAL: Total RNA was extracted from 23 pituitary adenomas obtained by transsphenoidal surgery, and subjected to Northern blot analyses using cDNAs of bovine Ad4BP/SF-1, porcine FSH-beta, LH-beta and glycoprotein hormone-alpha (GPH-alpha) subunts as radiolabelled probes. These adenomas included 13 clinically non-functioning adenomas, 1 GH/PRL-producing adenoma, 6 GH-producing adenomas, 2 PRL-producing adenomas and 1 ACTH-producing adenoma.
RESULTS: The expression of Ad4BP/SF-1 exactly coincided with the expression of FSH-beta. Thus 5 out of 13 clinically non-functioning adenomas expressed Ad4BP/SF-1 and only these 5 adenomas expressed FSH-beta. Interestingly, only one of the GH-producing adenomas also expressed Ad4BP/SF-1 as well as FSH-beta. GPH-alpha was expressed in 4 non-functioning adenomas and 2 hormonally functioning adenomas, but did not necessarily coincide with Ad4BP/SF-1 expression. None of the 23 adenomas we tested expressed LH-beta, probably because LH-beta-producing adenomas are rather rare.
CONCLUSIONS: The expression of FSH-beta was parallel with Ad4BP/SF-1 expression, indicating that the expression of Ad4BP/SF-1 is restricted to cells derived from gonadotroph lineages in human pituitary adenomas.

Harris PE, Alexander JM, Bikkal HA, et al.
Glycoprotein hormone alpha-subunit production in somatotroph adenomas with and without Gs alpha mutations.
J Clin Endocrinol Metab. 1992; 75(3):918-23 [PubMed] Related Publications
Activating mutations of the Gs alpha subunit have been identified in a subset of somatotroph adenomas. The mutant form of the Gs alpha subunit causes persistent activation of adenylyl cyclase and consequently results in high intracellular levels of cAMP. Because cAMP is known to stimulate the synthesis of the glycoprotein hormone (GPH) alpha-subunit as well as GH, we examined somatotroph tumors with and without Gs alpha mutations for GPH alpha-subunit production. GPH alpha-subunit production was assessed in vivo by measuring serum hormone levels and in vitro by analyzing hormone secretion by cultured pituitary tumor cells. DNA was extracted from the pituitary tumors of 26 acromegalic patients. The Gs alpha gene was amplified by the polymerase chain reaction and screened for mutations at codons 201 and 227 using oligonucleotide specific hybridization. Nine of the 26 tumors (35%) had point mutations at Arg 201. Seven of these tumors contained a CGT to TGT mutation (Arg to Cys) and 2 contained a CGT to CAT mutation (Arg to His). No mutations were detected at codon 227. There were no significant differences in age, sex distribution, tumor size, or serum levels of GH or insulin-like growth factor-1 between the groups of patients with or was Gs alpha mutations. The mean serum level of the free GPH alpha-subunit was 1.9-fold higher in the group with Gs alpha mutations (0.48 +/- 0.37 micrograms/L) than in patients without mutations (0.25 +/- 0.17) (P less than 0.05). In pituitary tumor cell culture, 75% of somatotroph tumors with Gs alpha mutations secreted free GPH alpha-subunit into the media compared with 45% of tumors without Gs alpha mutations. The amount of GPH alpha-subunit secretion was 12-fold greater in the group of tumors containing the Gs alpha mutation (P less than 0.05). Immunocytochemical detection of the free GPH alpha-subunit was similar in the two groups of patients with 75% positive for the GPH alpha-subunit in tumors with Gs alpha mutations and 67% positive in tumors without mutations (P = 0.69). We conclude that GPH alpha-subunit production occurs in somatotroph tumors with and without Gs alpha mutations. The increased levels of GPH alpha-subunit secretion in vivo and in vitro suggest that the Gs alpha mutation may increase the amount of preexisting GPH alpha-subunit biosynthesis in the tumors, perhaps via activation of the cAMP pathway.

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Cite this page: Cotterill SJ. GPHN, Cancer Genetics Web: http://www.cancer-genetics.org/GPHN.htm Accessed:

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