scholarly journals Dissecting the Roles of the Tuberin Protein in the Subcellular Localization of the G2/M Cyclin, Cyclin B1

2021 ◽  
Author(s):  
Jessica Dare-Shih ◽  
Adam Pillon ◽  
Jackie Fong ◽  
Elizabeth Fidalgo da Silva ◽  
Lisa Porter

Tuberin is a major component of the protein regulatory complex known as the Tuberous Sclerosis Complex and plays a crucial role in cell cycle progression and protein synthesis. Mutations in the Tuberin gene, TSC2, lead to the formation of benign tumors in many organ systems and causes the Tuberous Sclerosis Complex disorder. Genotypes ranging from point mutations to large deletions in the TSC2 gene have been clinically characterized with a wide range of phenotypes from skin tumors to large brain tumors. Our current work investigates the molecular mechanisms behind Tuberin and its ability to regulate the cell cycle through its binding to the G2/M cyclin, Cyclin B1. After creating an early stop codon in a critical region of the Tuberin, our results show the in vitro phenotype that occurs from a truncated Tuberin protein. Herein we demonstrate that this clinically relevant truncated form of Tuberin promotes an increased nuclear accumulation of Cyclin B1 and a subsequent increase in cell proliferation supporting the phenotypic data seen in the clinic with Tuberous Sclerosis Complex patients showing deletions within the TSC2 gene. This data provides an insight into some of the functional and molecular consequences of truncated proteins that are seen in clinical patients.

2020 ◽  
Vol 7 (3) ◽  
pp. 5-19
Author(s):  
Nikhil Nair ◽  
Ronith Chakraborty ◽  
Zubin Mahajan ◽  
Aditya Sharma ◽  
Sidarth Sethi ◽  
...  

Tuberous sclerosis complex (TSC) is a genetic condition caused by a mutation in either the TSC1 or TSC2 gene. Disruption of either of these genes leads to impaired production of hamartin or tuberin proteins, leading to the manifestation of skin lesions, tumors and seizures. TSC can manifests in multiple organ systems with the cutaneous and renal systems being the most commonly affected. These manifestations can secondarily lead to the development of hypertension, chronic kidney disease, and neurocognitive declines. The renal pathologies most commonly seen in TSC are angiomyolipoma, renal cysts and less commonly, oncocytomas. In this review, we highlight the current understanding on the renal manifestations of TSC along with current diagnosis and treatment guidelines.


2020 ◽  
Vol 7 (3) ◽  
pp. 5-19
Author(s):  
Nikhil Nair ◽  
Ronith Chakraborty ◽  
Zubin Mahajan ◽  
Aditya Sharma ◽  
Sidharth K. Sethi ◽  
...  

Tuberous sclerosis complex (TSC) is a genetic condition caused by a mutation in either the TSC1 or TSC2 gene. Disruption of either of these genes leads to impaired production of hamartin or tuberin proteins, leading to the manifestation of skin lesions, tumors, and seizures. TSC can manifest in multiple organ systems with the cutaneous and renal systems being the most commonly affected. These manifestations can secondarily lead to the development of hypertension, chronic kidney disease, and neurocognitive declines. The renal pathologies most commonly seen in TSC are angiomyolipoma, renal cysts, and less commonly, oncocytomas. In this review, we highlight the current understanding on the renal manifestations of TSC along with current diagnosis and treatment guidelines.


Author(s):  
Gajanan A. Surwade ◽  
Uddhav S. Khaire ◽  
Sagar P. Patil ◽  
Mamta K. Mulay ◽  
Mangala S. Borkar

<p class="abstract"><span lang="EN-US">Tuberous sclerosis is a neurocutaneous syndrome with an autosomal dominant inheritance. Tuberous sclerosis complex Syndrome caused by mutations of either the TSC1 orTSC2 gene encoding hamartin and tuberin respectively. It is characterized by the development of benign tumors; the most common oral manifestations of TSC are fibromas (angiofibromas), gingival hyperplasia and enamel hypoplasia and the formation of hamartomas in multiple organ systems leading to morbidity and mortality. Familial tuberous sclerosis probably occurs more often than is indicated by the literature: many family members show signs of being carriers of gene for the disease when carefully examined. We report a case of 25 year old female with the features of Tuberous sclerosis complex like seizures, papules over the cheek, shagreen patch, hypomelanotic macule on arm, buttacks, pulmonary lymphangioleiomyomatosis, subependymal nodules and tubers in brain, angiomyolipoma in both kidneys and Cardiac rhabdomyoma. This article reports on a family with documented tuberous sclerosis in three generations.</span></p>


2021 ◽  
pp. 95-96
Author(s):  
Fabricio Andrés Lasso Andrade ◽  
Jorge Alejandro Cadena Arteaga ◽  
Ángela Maria Fajardo Arteaga ◽  
Viviana Lizeth Echeverry Morillo ◽  
David Alfredo Acevedo Vargas ◽  
...  

Tuberous Sclerosis Complex (TSC) also known as Bournneville disease. TSC is a multisystemic genetic disorder with autosomal dominant inheritance, of variable expression, which is mainly characterized by the presence of benign tumors or hamartomas in the nervous system and skin, but which may also be present in the heart, kidney, lung and other organs. The most frequent symptom is epilepsy, affecting 80-90% of patients with TSC which manifests itself in childhood between 1 to 3 years of age. We present a case of sporadic onset tuberous sclerosis with epilepsy that had a causal link with TSC after admission to the emergency room in a convulsive status.


2017 ◽  
Vol 19 (2) ◽  
pp. 265-276 ◽  
Author(s):  
Nur Farrah Dila Ismail ◽  
Abdul Qawee Rani ◽  
Nik Mohd Ariff Nik Abdul Malik ◽  
Chia Boon Hock ◽  
Siti Nabilahuda Mohd Azlan ◽  
...  

2021 ◽  
pp. 98-105
Author(s):  
Julie Loft Nagel ◽  
Maja Patricia Smerdel ◽  
Lisbeth Birk Møller ◽  
Lotte Andreasen ◽  
Anette Bygum

Tuberous sclerosis complex (TSC) is an autosomal dominant hereditary disease with hamartomatous growths in multiple organs due to loss-of-function variants in TSC1 or TSC2. In approximately 15% of patients with clinical TSC, no pathogenic variant can be identified, and low-level mosaicism is suggested to be one of the reasons. Mosaicism is well-known in TSC and challenges the molecular genetic diagnosis. The advent of next-generation sequencing has improved the diagnostics in TSC including in patients with mosaicism. The TSC phenotype varies widely, and mosaic patients with TSC are often considered to have a milder phenotype. Here, the authors describe a patient with mosaic TSC with a 10% variant allele fraction and manifestations in three organ systems (skin, eyes, and kidneys). Furthermore, the authors studied existing literature about phenotypic organ manifestations in patients with mosaic TSC. No clear definition of the phenotype of patients with mosaic TSC could be established, but unilateral angiofibromas and the absence of tubers and a subependymal nodule could indicate mosaicism. The case shows that patients with low-level mosaic TSC can have multiple affected organ systems though still a mild clinical picture.


2019 ◽  
Vol 30 (4) ◽  
pp. 2199-2214
Author(s):  
Benoit Scherrer ◽  
Anna K Prohl ◽  
Maxime Taquet ◽  
Kush Kapur ◽  
Jurriaan M Peters ◽  
...  

Abstract Tuberous sclerosis complex (TSC) is a rare genetic disorder characterized by benign tumors throughout the body; it is generally diagnosed early in life and has a high prevalence of autism spectrum disorder (ASD), making it uniquely valuable in studying the early development of autism, before neuropsychiatric symptoms become apparent. One well-documented deficit in ASD is an impairment in face processing. In this work, we assessed whether anatomical connectivity patterns of the fusiform gyrus, a central structure in face processing, capture the risk of developing autism early in life. We longitudinally imaged TSC patients at 1, 2, and 3 years of age with diffusion compartment imaging. We evaluated whether the anatomical connectivity fingerprint of the fusiform gyrus was associated with the risk of developing autism measured by the Autism Observation Scale for Infants (AOSI). Our findings suggest that the fusiform gyrus connectivity captures the risk of developing autism as early as 1 year of age and provides evidence that abnormal fusiform gyrus connectivity increases with age. Moreover, the identified connections that best capture the risk of developing autism involved the fusiform gyrus and limbic and paralimbic regions that were consistent with the ASD phenotype, involving an increased number of left-lateralized structures with increasing age.


2019 ◽  
Vol 20 (1) ◽  
pp. 217-240 ◽  
Author(s):  
Catherine L. Salussolia ◽  
Katarzyna Klonowska ◽  
David J. Kwiatkowski ◽  
Mustafa Sahin

Tuberous sclerosis complex (TSC) is an autosomal dominant disorder that affects multiple organ systems due to an inactivating variant in either TSC1 or TSC2, resulting in the hyperactivation of the mechanistic target of rapamycin (mTOR) pathway. Dysregulated mTOR signaling results in increased cell growth and proliferation. Clinically, TSC patients exhibit great phenotypic variability, but the neurologic and neuropsychiatric manifestations of the disease have the greatest morbidity and mortality. TSC-associated epilepsy occurs in nearly all patients and is often difficult to treat because it is refractory to multiple antiseizure medications. The advent of mTOR inhibitors offers great promise in the treatment of TSC-associated epilepsy and other neurodevelopmental manifestations of the disease; however, the optimal timing of therapeutic intervention is not yet fully understood.


BMC Neurology ◽  
2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Valérie Mongrain ◽  
Nicolaas H. van Doesburg ◽  
Françoise Rypens ◽  
Catherine Fallet-Bianco ◽  
Justine Maassen ◽  
...  

Author(s):  
IE Hanes ◽  
N Abdeen ◽  
K Muir ◽  
E Sell

Background: Tuberous sclerosis complex (TSC) is characterized by growth of benign tumors in the skin, brain, kidneys, lung and heart. Prognosis is mostly determined by the extent of brain involvement as tumors in the brain lead to seizures and cognitive problems. Epilepsy is highly associated with the cognitive abnormalities in TSC and recent evidence suggests anti-epileptic treatment before onset of seizures reduces epilepsy severity and risk of mental retardation. Screening and potential identification of TSC in utero via ultrasound would allow for prophylactic seizure management in these children. The sensitivity of antenatal ultrasound in the identification of brain abnormalities associated with TSC has not yet been published. In this case, we review the antenatal ultrasounds of a child with TSC for evidence of brain abnormalities in utero. Methods: Retrospective review Results: Retrospective review of antenatal ultrasounds showed some evidence of intracranial abnormalities. Ultrasound at 34 weeks and 4 days gestation revealed an echogenic density in the right ventricle that correlates with SEGA on post-natal MRI brain at 12 days of life. Post-natal brain ultrasound at 37 weeks revealed multiple cranial abnormalities not seen in utero. Conclusions: There are limitations to antenatal neurosonography in the detection of intracranial abnormalities associated with TSC.


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