Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P42345 (mTOR)
 26,049 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

TSC1 and TSC2 are the tumour-suppressor genes mutated in the tumour syndrome TSC (tuberous sclerosis complex). Their gene products form a complex that has become the focus of many signal transduction researchers. The TSC1-TSC2 (hamartin-tuberin) complex, through its GAP (GTPase-activating protein) activity towards the small G-protein Rheb (Ras homologue enriched in brain), is a critical negative regulator of mTORC1 (mammalian target of rapamycin complex 1). As mTORC1 activity controls anabolic processes to promote cell growth, it is exquisitely sensitive to alterations in cell growth conditions. Through numerous phosphorylation events, the TSC1-TSC2 complex has emerged as the sensor and integrator of these growth conditions, relaying signals from diverse cellular pathways to properly modulate mTORC1 activity. In the present review we focus on the molecular details of TSC1-TSC2 complex regulation and function as it relates to the control of Rheb and mTORC1.
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PMID:The TSC1-TSC2 complex: a molecular switchboard controlling cell growth. 1846 15

Tuberous sclerosis complex (TSC) is an autosomal dominant disorder with an incidence of approximately one in 6000. It arises from a genetic abnormality involving either the TSC1 gene on chromosome 9 or the TSC2 gene on chromosome 16. The protein product of TSC1 is hamartin and that of TSC2 is tuberin. In cells, hamartin and tuberin form a complex which inhibits the mammalian target of rapamycin (mTOR), a central controller of cell growth and proliferation. Angiofibroma affects 70-80% of patients with TSC, typically on the face. We report a patient with TSC with recurrent life-threatening haemorrhage from both kidneys due to extensive angiomyolipoma formation leading to bilateral nephrectomy and renal transplantation. Immunosuppressive treatment with rapamycin, a specific mTOR inhibitor, initiated because of renal transplantation, reduced facial angiofibroma dramatically.
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PMID:The mTOR inhibitor rapamycin significantly improves facial angiofibroma lesions in a patient with tuberous sclerosis. 1854 4

Tuberin, a tumor-suppressor protein produced by the tuberous sclerosis gene TSC2, downregulates the Rheb-mTOR-S6K pathway (mTOR axis). Comparison of the effects of human tuberin mutations, such as G1556S, suggests that pathways other than the mTOR axis might also be involved in the pathogenesis of tuberous sclerosis. Here we test this possibility using the rat G1556S-type mutation (GSM) and a transgenic Eker (Tsc2 mutant) rat system. Cells expressing GSM-tuberin failed to downregulate the mTOR axis. GSM-tuberin had an altered localization, which underlie its reduced ability to form a complex with hamartin, and a site-specific alteration in phosphorylation status indicating diverse regulation by Akt. GSM-transgenic (GSM-Tg) rats exhibited suppression of macroscopic renal tumors following N-ethyl-N-nitrosourea treatment. Intriguingly, rats with weaker GSM-Tg expression showed microscopic cystic and pre-tumorous lesions that were restricted in size and expansion, although they had hyper-phosphorylation of ribosomal protein S6. These results highlight a novel pathway involving tuberin that regulates tumor suppression independently of the mTOR inhibitory function. Identification of such a novel pathway will provide clear implications for generation of new therapeutic targets in the treatment of these tumors.
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PMID:The G1556S-type tuberin variant suppresses tumor formation in tuberous sclerosis 2 mutant (Eker) rats despite its deficiency in mTOR inhibition. 1869 78

Tuberous sclerosis complex (TSC) is a tumor suppressor gene syndrome in which severe renal cystic disease can occur. Many renal cystic diseases, including autosomal dominant polycystic kidney disease (ADPKD), are associated with absence or dysfunction of the primary cilium. We report here that hamartin (TSC1) localizes to the basal body of the primary cilium, and that Tsc1(-/-) and Tsc2(-/-) mouse embryonic fibroblasts (MEFs) are significantly more likely to contain a primary cilium than wild-type controls. In addition, the cilia of Tsc1(-/-) and Tsc2(-/-) MEFs are 17-27% longer than cilia from wild-type MEFs. These data suggest a novel type of ciliary disruption in TSC, associated with enhanced cilia development. The TSC1 and TSC2 proteins function as a heterodimer to inhibit the activity of the mammalian target of rapamycin complex 1 (TORC1). The enhanced ciliary formation in the Tsc1(-/-) and Tsc2(-/-) MEFs was not abrogated by rapamycin, which indicates a TORC1-independent mechanism. Polycystin 1 (PC1), the product of the PKD1 gene, has been found to interact with TSC2, but Pkd1(-/-) MEFs did not have enhanced ciliary formation. Furthermore, while activation of mTOR has been observed in renal cysts from ADPKD patients, Pkd1(-/-) MEFs did not have evidence of constitutive mTOR activation, thereby underscoring the independent functions of the TSC proteins and PC1 in regulation of primary cilia and mTOR. Our data link the TSC proteins with the primary cilium and reveal a novel phenotype of enhanced ciliary formation in a cyst-associated disease.
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PMID:The tuberous sclerosis proteins regulate formation of the primary cilium via a rapamycin-insensitive and polycystin 1-independent pathway. 1884 92

The genes TSC1 and TSC2, encoding hamartin and tuberin, respectively, have been shown to be involved in the development of the autosomal dominantly inherited tumor syndrome tuberous sclerosis (TSC). However, inactivation of these genes has also been demonstrated to be associated with sporadic bladder cancer, ovarian and gall bladder carcinoma, non-small-cell carcinoma of the lung, breast cancer, pancreatic cancer, astrocytoma, xanthoastrocytoma, ependymomas, oral squamous cell carcinoma and endometrial cancer. The hamartin/tuberin protein complex plays a central role in the regulation of the mammalian target of rapamycin (mTOR) signalling network. A wide variety of components of the mTOR cascade have been demonstrated to be involved in many different human cancers. Mutations in several mTOR pathway component genes are known to cause specific monogenic human genetic diseases and this signalling cascade has been shown to be of relevance for Alzheimer's disease, type 2 diabetes, obesity and hypertrophy. Consequently, e.g. clinical trials for the treatment with rapamycin, a negative regulator of mTOR, of hamartomas in TSC have already been initiated. Now the first evidence is provided for an involvement of the TSC genes in acute leukemia.
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PMID:New insights into the role of the tuberous sclerosis genes in leukemia. 1925 Jun 71

Tuberous sclerosis complex (TSC) is a relatively rare autosomal dominant disorder characterized by widespread benign tumor formation in a variety of organs. Mutations in either TSC1 or TSC2 tumor suppressor gene are responsible for TSC. The gene products of TSC1 and TSC2, also known as hamartin and tuberin, respectively, form a physical and functional complex and inhibit the mammalian target of rapamycin complex 1 (mTORC1) signaling. The mTORC1 pathway is an evolutionarily conserved growth promoting pathway. mTORC1 plays an essential role in a wide array of cellular processes including translation, transcription, trafficking and autophagy. In this review, we will discuss recent progresses in the TSC-mTOR field and their physiological functions and alterations of this pathway in pathophysiology.
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PMID:Tuberous sclerosis complex, implication from a rare genetic disease to common cancer treatment. 1929 7

Tuberous Sclerosis Complex is a multisystem disorder exhibiting a wide range of manifestations characterized by tumour-like lesions called hamartomas in the brain, skin, eyes, heart, lungs and kidneys. Tuberous Sclerosis Complex is genetically determined with an autosomal dominant inheritance and is caused by inactivating mutations in either the TSC1 or TSC2 genes. TSC1/2 genes play a fundamental role in the regulation of phosphoinositide 3-kinase (PI3K) signalling pathway, inhibiting the mammalian target of rapamycin (mTOR) through activation of the GTPase activity of Rheb. Mutations in TSC1/2 genes impair the inhibitory function of the hamartin/tuberin complex, leading to phosphorylation of the downstream effectors of mTOR, p70 S6 kinase (S6K), ribosomal protein S6 and the elongation factor binding protein 4E-BP1, resulting in uncontrolled cell growth and tumourigenesis.Despite recent promising genetic, diagnostic, and therapeutic advances in Tuberous Sclerosis Complex, continuing research in all aspects of this complex disease will be pivotal to decrease its associated morbidity and mortality. In this review we will discuss and analyse all the important findings in the molecular pathogenesis of Tuberous Sclerosis Complex, focusing on genetics and the molecular mechanisms that define this multisystemic disorder.
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PMID:Genetics and molecular biology of tuberous sclerosis complex. 1950 36

Herein we have reported the use of rapamycin in immunosuppressive treatment after renal transplantation as a therapy of choice in a patient with diagnosis of tuberous sclerosis complex (TSC). TSC is a genetic disorder, caused by mutations of TSC1 or TSC2 genes. Products of these genes, hamartin and tuberin, create a complex that inhibits mammalian target of rapamycin (mTOR), a key protein engaged in regulation of the cell cycle. Mutations of TSC genes lead to constitutive activation of mTOR resulting in uncontrolled proliferation, differentiation, and migration of cells. As a consequence malformations of many organs arise. We have presented a case of a 47-year-old female TSC patient with multisystem involvement (skin, brain, lungs, and kidneys), who developed end-stage renal disease ESRD due to angiomyolipomas with subsequent bilateral nephrectomy. At the age of 44 years, she started hemodialysis treatments and 10 months later underwent kidney transplantation. Immunosuppressive treatment included the mTOR inhibitor rapamycin. Since the patient was discharged from hospital, she has remained in good clinical condition with stable graft function. Clinical evaluation after 2 years treatment with rapamycin revealed significant regression of skin lesions. Brain, chest, and abdominal cavity computed tomography images remained stable. No complications of immunosuppressive treatment or TSC were observed. Experimental and clinical studies have confirmed that rapamycin exerts beneficial effects in TSC, providing a new therapeutic option. Therefore an immunosuppressive regimen with rapamycin should be considered as the treatment of choice after kidney transplantation among patients with TSC seeking to avoid development or progression of disease complications.
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PMID:Rapamycin as a therapy of choice after renal transplantation in a patient with tuberous sclerosis complex. 1991 66

Tuberous sclerosis complex 1 (TSC1) inhibits mammalian target of rapamycin (mTOR), a central promotor of cell growth and proliferation. The protein product of the TSC1 gene, hamartin (referred to as TSC1) is known to interact with Polo-like kinase 1 (Plk1) in a cell cycle regulated, phosphorylation-dependent manner. We hypothesized that the p53 target gene, Plk2, is a tumor suppressor, mediating its tumor suppressor function through interactions with TSC1 that facilitate TSC1/2 restraint of mTOR under hypoxic stress. We found that human lung tumor cells deficient in Plk2 grew larger than control tumors, and that Plk2 interacts with endogenous TSC1 protein. Additionally, C-terminal Plk2-GST fusion protein bound both TSC1 and TSC2 proteins. TSC1 levels were elevated in response to Adriamycin and cells transiently overexpressing Plk2 demonstrated decreased phosphorylation of the downstream target of mTOR, ribosomal protein p70S6 kinase during hypoxia. Plk2 levels were inversely correlated with cytoplasmic p70S6K phosphorylation. Plk2 levels did not increase in response to DNA damage (Adriamycin, CPT -11) when HCT 116 and H460 cells were exposed to hypoxia. TSC1-deficient mouse embryonic fibroblasts with TSC1 added back demonstrated decreased S6K phosphorylation, which was further decreased when Plk2 was transiently overexpressed. Interestingly, under normoxia, Plk2 deficient tumor cells demonstrated increased apoptosis in response to various chemotherapeutic agents including CPT -11 but increased resistance to apoptotic death after CPT-11 treatment under hypoxia, and tumor xenografts comprised of these Plk2-deficient cells were resistant to CPT -11. Our results point to a novel Plk2-TSC1 interaction with effects on mTOR signaling during hypoxia, and tumor growth that may enable targeting Plk2 signaling in cancer therapy.
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PMID:The p53 target Plk2 interacts with TSC proteins impacting mTOR signaling, tumor growth and chemosensitivity under hypoxic conditions. 2005 36

Tuberous sclerosis complex (TSC) is an autosomal dominant multisystem neurocutaneous syndrome characterized by the development of multiple hamartomas distributed throughout the body, skin, brain, eyes, heart, kidney and lung. The affected genes are TSC1 and TSC2, encoding hamartin and tuberin respectively. The hamartin-tuberin complex inhibits the mammalian target of rapamycin pathway, which controls cell growth and proliferation. The most common neurological manifestations of TSC are epilepsy, mental retardation, and autistic behavior. Epilespsy usually occurs during childhood and they need anticonvulsant medications through their life. In adulthood, multiple hamartomas is distributed in the kidney and lung. Individuals with lesions more than 4 cm in diameter or with extensive renal involvement should be referred to a nephrologist or urologist. Understanding variable phenotype expression improve management of TSC.
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PMID:[Care continuity for patients with tuberous sclerosis complex (TSC) during transition from childhood to adulthood]. 2007 6


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