Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P43146 (tumour suppressor)
 5,935 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Tuberous sclerosis (TSC) is an autosomal dominant trait characterized by the widespread development of benign tumours classified as hamartoma, and is often associated with seizures and mental retardation. The patchy distribution and focal nature of the growths suggests that they might result from inactivation of a tumour suppressor gene by a two-hit process. Over the last 2 years, studies designed to investigate both germline and somatic TSC mutations have lent support to this hypothesis. Analysis of TSC-associated hamartomas has shown loss of heterozygosity for the regions of chromosomes 9 and 16 known to harbour TSC genes, consistent with the occurrence of somatic 'second-hit' mutations. Parallel investigations using pulse field gel electrophoresis have identified constitutional deletions representing 'first-hit' mutations at 16p13.3, leading to the rapid identification of one of the causative genes, TSC2. Intriguingly, the TSC2 product, tuberin, has an area of sequence homology with the GTPase activating protein rap1GAP, suggesting a possible mechanism for its role in regulating cellular growth.
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PMID:The molecular genetics of tuberous sclerosis. 784 41

Germ-line mutations of the TSC2 tumour suppressor gene have been identified in humans with tuberous sclerosis and in the Eker rat. Tuberin, the human TSC2 gene product, has a small region of homology with rap1GAP and stimulates rap1 GTPase activity in vitro, suggesting that one of its cellular roles is to function as a GTPase activating protein (GAP). We have undertaken a comparative analysis of the TSC2 gene in human and the pufferfish, Fugu rubripes. In addition to the GAP domain, three other regions of the proteins are highly conserved (peptide sequence similarity > 80%). These regions are likely to represent further functional domains. To facilitate analysis of mutations within these domains we have determined the genomic structure of the human TSC2 gene. It comprises 41 exons, including exon 31 which was absent from the originally described spliceoform of the human TSC2 transcript and was identified following exon prediction from Fugu genomic sequence. These findings support the proposal of the Fugu genome as a tool for human gene analysis.
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PMID:Comparative analysis and genomic structure of the tuberous sclerosis 2 (TSC2) gene in human and pufferfish. 884 53

Tuberous sclerosis is an autosomal dominant trait in which the dysregulation of cellular proliferation and differentiation results in the development of hamartomatous growths in many organs. The TSC2 gene is one of two genes determining tuberous sclerosis. Inactivating germline mutations of TSC2 in patients with tuberous sclerosis and somatic loss of heterozygosity at the TSC2 locus in the associated hamartomas indicate that TSC2 functions as a tumour suppressor gene and that loss of function is critical to expression of the tuberous sclerosis phenotype. The TSC2 product, tuberin, has a region of homology with the GTPase activating protein rap1GAP and stimulates the GTPase activity of rap1a and rab5a in vitro. Here we show that the region of homology between tuberin and human rap1GAP and the murine GAP mSpa1 is more extensive than previously reported and spans approximately 160 amino acid residues encoded within exons 34-38 of the TSC2 gene. Single strand conformation polymorphism analysis of these exons in 173 unrelated patients with tuberous sclerosis and direct sequencing of variant conformers together with study of additional family members enabled characterisation of disease associated mutations in 14 cases. Missense mutations, which occurred in exons 36, 37 and 38 were identified in eight cases, four of whom shared the same recurrent change P1675L. Each of the five different missense mutations identified was shown to occur de novo in at least one sporadic case of tuberous sclerosis. The high proportion of missense mutations detected in the region of the TSC2 gene encoding the GAP-related domain supports its key role in the regulation of cellular growth.
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PMID:The GAP-related domain of tuberin, the product of the TSC2 gene, is a target for missense mutations in tuberous sclerosis. 930 81

A 16-mer peptide library was screened using the yeast two-hybrid system to identify peptides which specifically interact with the human papillomavirus type 16 (HPV-16) E6 protein. Four different peptides were identified, three of which contained an E-L-L/V-G motif. A fifth E6 binding peptide, derived from the putative tumour suppressor protein tuberin, was identified during a two-hybrid screen of a HeLa cDNA expression library. This peptide contained a D-I-L-G motif. Homology to the peptides was found within the E6 binding proteins E6-AP and E6-BP. A synthetic peptide containing the ELLG motif blocked the interaction of E6 with both E6-AP and E6-BP. The data suggest that E6 interacts through a structurally similar binding domain present within a number of cellular proteins.
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PMID:The identification of a conserved binding motif within human papillomavirus type 16 E6 binding peptides, E6AP and E6BP. 947 22

Tuberous sclerosis (TSC) is an autosomal dominant disorder caused by a mutation in either the TSC1 or TSC2 tumour suppressor gene. The disease is characterized by a broad phenotypic spectrum that can include seizures, mental retardation, renal dysfunction and dermatological abnormalities. TSC2 encodes tuberin, a putative GTPase activating protein for rap1 and rab5. The TSC1 gene was recently identified and codes for hamartin, a novel protein with no significant homology to tuberin or any other known vertebrate protein. Here, we show that hamartin and tuberin associate physically in vivo and that the interaction is mediated by predicted coiled-coil domains. Our data suggest that hamartin and tuberin function in the same complex rather than in separate pathways.
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PMID:Interaction between hamartin and tuberin, the TSC1 and TSC2 gene products. 958 Jun 71

Tuberous sclerosis is an autosomal dominant disorder. Besides the development of benign growths (hamartomas) in different tissues, one hallmark of this disease is the presence of highly epileptogenic dysplastic lesions in the cerebral cortex (tubers) composed of abnormal shaped neurones. Patients often show evidence of severe mental retardation. Linkage analysis revealed two disease-determining genes on chromosome 9 and chromosome 16. The TSC2 gene on chromosome 16 encodes a 1784-amino acid putative tumour suppressor protein, tuberin, that functions as a GTPase-activating protein. Here we show that tuberin expression is upregulated upon induction of neuronal differentiation in the neuroblastoma cell lines SK-N-SH and LAN-1. This upregulation occurs at post-transcriptional level and is independent of the proliferation status. TSC2 expression is unaffected during differentiation of C2C12 myoblasts into myotubes and of F9 embryonal carcinoma cells into cells resembling parietal endoderm. Antisense inhibition of tuberin expression in SK-N-SH or LAN-1 cells inhibits neuronal differentiation, but does not affect the differentiation of F9 cells. Ectopic overexpression of TSC2 not only reverts the antisense-associated phenotype but furthermore accelerates the neuronal differentiation process. Our data show for the first time that tuberin plays a critical role in neuronal differentiation. Such role is consistent with the phenotype of tuberous sclerosis patients, who inherit one defective TSC2 allele, and frequently lose the remaining normal allele in many of the tubers/hamartomas which develop in the central nervous system of these patients.
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PMID:A role of the tuberous sclerosis gene-2 product during neuronal differentiation. 961 28

The murine t complex on chromosome 17 contains a number of homozygous lethal and semi-lethal mutations that disrupt development of the mouse embryo. We recently characterized an embryonic lethality in the rat that results from a germ-line mutation in the tuberous sclerosis 2 (Tsc-2) tumour suppressor gene (the Eker mutation). Remarkably, mouse embryos homozygous for tw8 mutation display cranial defects reminiscent of those observed in rat embryos homozygous for the Eker mutation. To determine whether the Tsc-2 gene, which is in the t complex, is mutated in tw8 or other t haplotypes, we characterized this gene in a series of t haplotype mice. Four Tsc-2 polymorphisms were identified: three in the coding region and one intronic that appeared to be common to all t haplotypes analysed. No evidence was found to argue that the Tsc-2 gene is altered in tw8 haplotype mice. However, in the tw5 haplotype we found a G to T mutation in Tsc-2 that was present only in this t haplotype. In contrast to other polymorphisms within the Tsc-2 coding region which did not result in amino acid changes in Tsc-2 gene product tuberin, this mutation substituted a phenylalanine for a conserved cysteine in tw5 tuberin. Within the t complex, the Tsc-2 gene and the putative tw5 locus appeared to map to different positions, complicating identification of Tsc-2 as a candidate for the tw5 locus and suggesting that the G to T mutation in the Tsc-2 gene may have arisen independently of the tw5 functional mutation.
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PMID:Genetic variants of the tuberous sclerosis 2 tumour suppressor gene in mouse t haplotypes. 1058 58

Reduced expression of the TSC2 tumour suppressor gene product, tuberin, has been reported in sporadic astrocytomas, suggesting that the TSC genes may play a role in formation of sporadic glial or glioneuronal tumours. We studied paired constitutional and tumour DNA samples from 100 patients with sporadic glial and glioneuronal tumours for loss of heterozygosity (LOH) at the TSC1 and TSC2 loci using a combination of seven previously reported and seven novel polymorphic markers. LOH was seen in 1/16 astrocytomas, 3/15 ependymomas, 5/16 gangliogliomas, 2/14 glioblastoma multiforme, 0/7 oligodendrogliomas, 0/7 tumours of mixed oligodendrocytic/astrocytic histology, 2/11 pilocytic astrocytomas and 0/1 subependymal giant cell astrocytomas informative at both loci. However, SSCP screening of all coding exons of the TSC1 or TSC2 genes in the tumours displaying LOH, and of both genes in 21 gangliogliomas, revealed no intragenic mutations. The lack of demonstrable inactivation of both alleles of either TSC gene in any of the tumours investigated suggests that they do not play a frequent role in the aetiology of sporadic glial or glioneuronal tumours.
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PMID:Molecular analysis of the TSC1 and TSC2 tumour suppressor genes in sporadic glial and glioneuronal tumours. 1112 34

Tuberous sclerosis (TSC) is an autosomal dominant disorder characterized by a broad phenotypic spectrum that includes seizures, mental retardation, renal dysfunction and dermatological abnormalities. Inactivating mutations to either of the TSC1 and TSC2 tumour suppressor genes are responsible for the disease. TSC1 and TSC2 encode two large novel proteins called hamartin and tuberin, respectively. Hamartin and tuberin interact directly with each other and it has been reported that tuberin may act as a chaperone, preventing hamartin self-aggregation and maintaining the tuberin-hamartin complex in a soluble form. In this study, the ability of tuberin to act as a chaperone for hamartin was used to investigate the tuberin-hamartin interaction in more detail. A domain within tuberin necessary for the chaperone function was identified, and the effects of TSC2 missense mutations on the tuberin-hamartin interaction were investigated to allow specific residues within the central domain of tuberin that are important for the interaction with hamartin to be pin-pointed. In addition, the results confirm that phosphorylation may play an important role in the formation of the tuberin-hamartin complex. Although mutations that prevent tuberin tyrosine phosphorylation also inhibit tuberin-hamartin binding and the chaperone function, our results indicate that only hamartin is phosphorylated in the tuberin-hamartin complex.
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PMID:TSC2 missense mutations inhibit tuberin phosphorylation and prevent formation of the tuberin-hamartin complex. 1174 32

Tuberous sclerosis complex (TSC) is an autosomal dominant disorder caused by mutations to the TSC1 and TSC2 tumour suppressor genes. We detected two sequence changes involving the TSC2 stop codon and investigated the effects of these changes on the expression of tuberin, the TSC2 gene product, and on the binding between tuberin and the TSC1 gene product, hamartin. While elongation of the tuberin open reading frame by 17 amino acids did not interfere with tuberin-hamartin binding, a longer extension prevented this interaction. Our data illustrate how functional protein assays can assist in the verification and characterisation of disease-causing mutations.
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PMID:Analysis of TSC2 stop codon variants found in tuberous sclerosis patients. 1178 98


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