Read by QxMD icon Read


Teklab Gebregiworgis, Christopher Boyd Marshall, Tadateru Nishikawa, Nikolina Radulovich, María-José Sandi, Zhenhao Fang, Robert Rottapel, Ming-Sound Tsao, Mitsuhiko Ikura
Small GTPases (sGTPases) are critical switch-like regulators that mediate several important cellular functions and are often mutated in human cancers. They are activated by guanine nucleotide exchange factors (GEFs), which specifically catalyze the exchange of GTP for GDP. GEFs coordinate signaling networks in normal cells, and are frequently deregulated in cancers. sGTPase signaling pathways are complex and interconnected; however, most GEF assays do not reveal such complexity. In this communication, we describe the development of a unique real-time NMR-based multiplexed GEF assay that employs distinct isotopic labeling schemes for each sGTPase protein to enable simultaneous observation of six proteins of interest...
March 15, 2018: Journal of the American Chemical Society
Yujie Li, Sandra Finkbeiner, Athina Ganner, Julia Gerber, Marinella Klein, Manuel Grafe, Jakob Kandzia, Antje Thien, Kathrin Thedieck, Gerhard Breves, Thomas Jank, Ralf Baumeister, Gerd Walz, Elke Neumann-Haefelin
The mechanistic target of rapamycin (mTOR) kinase is central to metabolism and growth, and has a conserved role in aging. mTOR functions in two complexes, mTORC1 and mTORC2. In diverse eukaryotes, inhibition of mTORC1 signaling increases lifespan. mTORC1 transduces anabolic signals to stimulate protein synthesis and inhibits autophagy. In this study, we demonstrate that CGEF-1, the C. elegans homolog of the human guanine nucleotide exchange factor Dbl, is a novel binding partner of RHEB-1 and activator of mTORC1 signaling in C...
February 9, 2018: Oncotarget
Sidney Abou Sawan, Stephan van Vliet, Justin T Parel, Joseph W Beals, Michael Mazzulla, Daniel W D West, Andrew Philp, Zhong Li, Scott A Paluska, Nicholas A Burd, Daniel R Moore
Translocation and colocalization of mechanistic target of rapamycin complex 1 (mTORC1) with regulatory proteins represents a critical step in translation initiation of protein synthesis in vitro. However, mechanistic insight into the control of postprandial skeletal muscle protein synthesis rates at rest and after an acute bout of endurance exercise in humans is lacking. In crossover trials, eight endurance-trained men received primed-continuous infusions of L-[ring-2 H5 ]phenylalanine and consumed a mixed-macronutrient meal (18 g protein, 60 g carbohydrates, 17 g fat) at rest (REST) and after 60 min of treadmill running at 70% VO2peak (EX)...
March 2018: Physiological Reports
Li Zhou, Shunai Liu, Ming Han, Yanhua Ma, Shenghu Feng, Jing Zhao, Hongping Lu, Xiaoxue Yuan, Jun Cheng
Recent studies have shown the effect of microRNAs on HSC activation and transformation, which is essential for the pathogenesis of liver fibrosis. In our study, we explored the role of miR-185 in liver fibrosis. Plasma miR-185 was detected in hepatitis B virus-related liver fibrosis patients (S2/3, n = 10) by Illumina HiSeq sequencing, and healthy volunteers were selected (n = 8) as the control group. We found that the plasma miR-185 level in fibrosis patients was significantly downregulated. CCl4 -induced fibrosis tissues in mouse livers and TGF-β1-activated HSCs also presented downregulated miR-185 concomitant with an increased expression of RHEB and RICTOR...
March 2, 2018: Molecular Therapy. Nucleic Acids
Fuchen Liu, Zeya Pan, Jinmin Zhang, Junsheng Ni, Chao Wang, Zhenguang Wang, Fangming Gu, Wei Dong, Weiping Zhou, Hui Liu
Aberrant expression of Ras homolog enriched in brain (RHEB) has been observed in a variety of cancer tissues and is closely associated with clinicopathological features. However, the expression profile of RHEB in patients with hepatocellular carcinoma (HCC) and its clinical signature with underlying mechanisms have not been explored thus far. To analyze the association between RHEB expression and clinicopathological features, the RHEB expression levels were determined in the present study using gene microarrays, immunohistochemistry and western blotting in 60 liver cancer tissues and 35 normal liver tissues...
March 2018: Oncology Letters
Mark W Urban, Biswarup Ghosh, Laura R Strojny, Cole G Block, Sara M Blazejewski, Megan C Wright, George M Smith, Angelo C Lepore
Damage to respiratory neural circuitry and consequent loss of diaphragm function is a major cause of morbidity and mortality in individuals suffering from traumatic cervical spinal cord injury (SCI). Repair of CNS axons after SCI remains a therapeutic challenge, despite current efforts. SCI disrupts inspiratory signals originating in the rostral ventral respiratory group (rVRG) of the medulla from their phrenic motor neuron (PhMN) targets, resulting in loss of diaphragm function. Using a rat model of cervical hemisection SCI, we aimed to restore rVRG-PhMN-diaphragm circuitry by stimulating regeneration of injured rVRG axons via targeted induction of Rheb (ras homolog enriched in brain), a signaling molecule that regulates neuronal-intrinsic axon growth potential...
February 14, 2018: Experimental Neurology
Aidan M Sokolov, Caitlin M Seluzicki, Mary C Morton, David M Feliciano
Ras homology enriched in brain (Rheb) is a GTPase that activates the protein kinase mammalian Target of Rapamycin (mTOR). Rheb mutations cause intellectual delay and megalencephaly. mTOR hyperactivation causes a constellation of neurodevelopmental disorders called "mTOR-opathies" that are frequently accompanied by hyperexcitable cortical malformations. Cortical malformations within the anterior cingulate cortex (ACC) and somatosensory cortex (SSC) frequently colocalize with hyperexcitability. Although Rheb and mTOR are implicated in the formation of cortical lesions, seizure activity, and defects in neuronal migration, the contribution of Rheb to changes in neuron size and dendrite morphology is not well established...
February 12, 2018: Neuroscience Letters
Sehwan Kim, Gyeong Joon Moon, Yong-Seok Oh, Jungha Park, Won-Ho Shin, Jae Yeong Jeong, Kwang Shik Choi, Byung Kwan Jin, Nikolai Kholodilov, Robert E Burke, Hyung-Jun Kim, Chang Man Ha, Seok-Geun Lee, Sang Ryong Kim
We recently reported that adeno-associated virus serotype 1 (AAV1) transduction of murine nigral dopaminergic (DA) neurons with constitutively active ras homolog enriched in brain with a mutation of serine to histidine at position 16 [Rheb(S16H)] induced the production of neurotrophic factors, resulting in neuroprotective effects on the nigrostriatal DA system in animal models of Parkinson's disease (PD). To further investigate whether AAV1-Rheb(S16H) transduction has neuroprotective potential against neurotoxic inflammation, which is known to be a potential event related to PD pathogenesis, we examined the effects of Rheb(S16H) expression in nigral DA neurons under a neurotoxic inflammatory environment induced by the endogenous microglial activator prothrombin kringle-2 (pKr-2)...
February 9, 2018: Experimental & Molecular Medicine
Da-Peng Chen, Ye-Ping Ma, Li Zhuo, Zheng Zhang, Gu-Ming Zou, Yue Yang, Hong-Mei Gao, Wen-Ge Li
1,25-Dihydroxyvitamin D3(1,25(OH)2 D3) is a secosteroid with antiproliferative property. It also plays a pivotal renoprotective role in diabetic nephropathy. We investigated whether 1,25(OH)2D3 could inhibit the proliferation of rat mesangial cells exposed to high glucose via the DNA-damage-inducible transcript 4/mammalian target of rapamycin(DDIT4/mTOR) pathway. The cell proliferation rate and cell cycle duration were measured using cell counting kit-8 assay and flow cytometry. Protein expression was assayed by Western blot...
January 2, 2018: Oncotarget
Sarah J Mahoney, Sridhar Narayan, Lisa Molz, Lauren A Berstler, Seong A Kang, George P Vlasuk, Eddine Saiah
The small G-protein Rheb activates the mechanistic target of rapamycin complex 1 (mTORC1) in response to growth factor signals. mTORC1 is a master regulator of cellular growth and metabolism; aberrant mTORC1 signaling is associated with fibrotic, metabolic, and neurodegenerative diseases, cancers, and rare disorders. Point mutations in the Rheb switch II domain impair its ability to activate mTORC1. Here, we report the discovery of a small molecule (NR1) that binds Rheb in the switch II domain and selectively blocks mTORC1 signaling...
February 7, 2018: Nature Communications
Jeffrey J Heard, Ivy Phung, Mark I Potes, Fuyuhiko Tamanoi
BACKGROUND: RHEB is a unique member of the RAS superfamily of small GTPases expressed in all tissues and conserved from yeast to humans. Early studies on RHEB indicated a possible RHEB-RAF interaction, but this has not been fully explored. Recent work on cancer genome databases has revealed a reoccurring mutation in RHEB at the Tyr35 position, and a recent study points to the oncogenic potential of this mutant that involves activation of RAF/MEK/ERK signaling. These developments prompted us to reassess the significance of RHEB effect on RAF, and to compare mutant and wild type RHEB...
January 10, 2018: BMC Cancer
(no author information available yet)
RHEB promotes allosteric activation of mTOR whereas PRAS40 blocks substrate recruitment sites.
January 5, 2018: Cancer Discovery
Lingjie Wang, Junlong Du, Fangyu Zhao, Zonghai Chen, Jingru Chang, Furong Qin, Zili Wang, Fengjie Wang, Xianbing Chen, Ning Chen
During the expansion of aging population, the study correlated with brain aging is one of the important research topics. Developing novel and effective strategies for delaying brain aging is highly desired. Brain aging is characteristics of impaired cognitive capacity due to dysfunctional autophagy regulated by Rheb-mTOR signal pathway in hippocampal tissues. In the present study, we have established a rat model with brain aging through subcutaneous injection of D-galactose (D-gal). Upon the intervention of Trillium tschonoskii Maxim (TTM) saponin, one of bioactive components from local natural herbs in China, the learning and memory capacity of D-gal-induced aging rats was evaluated through Morris water maze test, and the regulation of Rheb-mTOR signal pathway and functional status of autophagy in hippocampal tissues of D-gal-induced aging rats was explored by Western blot...
December 26, 2017: Biomedicine & Pharmacotherapy, Biomédecine & Pharmacothérapie
Haijuan Yang, Xiaolu Jiang, Buren Li, Hyo J Yang, Meredith Miller, Angela Yang, Ankita Dhar, Nikola P Pavletich
The mechanistic target of rapamycin complex 1 (mTORC1) controls cell growth and metabolism in response to nutrients, energy levels, and growth factors. It contains the atypical kinase mTOR and the RAPTOR subunit that binds to the Tor signalling sequence (TOS) motif of substrates and regulators. mTORC1 is activated by the small GTPase RHEB (Ras homologue enriched in brain) and inhibited by PRAS40. Here we present the 3.0 ångström cryo-electron microscopy structure of mTORC1 and the 3.4 ångström structure of activated RHEB-mTORC1...
December 13, 2017: Nature
Feike Hao, Kazuhiko Kondo, Takashi Itoh, Sumiko Ikari, Shigeyuki Nada, Masato Okada, Takeshi Noda
In response to amino acid supply, mTORC1, a master regulator of cell growth, is recruited to the lysosome and activated by the small GTPase Rheb. However, the intracellular localization of Rheb is controversial. In this study, we showed that a significant portion of Rheb is localized on the Golgi but not on the lysosome. GFP-Rheb could activate mTORC1, even when forced to exclusively localize to the Golgi. Likewise, artificial recruitment of mTORC1 to the Golgi allowed its activation. Accordingly, the Golgi was in contact with the lysosome at an newly discovered area of the cell that we term the Golgi-lysosome contact site (GLCS)...
January 29, 2018: Journal of Cell Science
Jun-Hung Cho, Bhaumik Patel, Santosh Bonala, Sasikanth Manne, Yan Zhou, Surya K Vadrevu, Jalpa Patel, Marco Peronaci, Shanawaz Ghouse, Elizabeth P Henske, Fabrice Roegiers, Krinio Giannikou, David J Kwiatkowski, Hossein Mansouri, Maciej M Markiewski, Brandon White, Magdalena Karbowniczek
Differentiation abnormalities are a hallmark of tuberous sclerosis complex (TSC) manifestations; however, the genesis of these abnormalities remains unclear. Here we report on mechanisms controlling the multi-lineage, early neuronal progenitor and neural stem-like cell characteristics of lymphangioleiomyomatosis (LAM) and angiomyolipoma cells. These mechanisms include the activation of a previously unreported Rheb-Notch-Rheb regulatory loop, in which the cyclic binding of Notch1 to the Notch-responsive elements (NREs) on the Rheb promoter is a key event...
November 29, 2017: Nature Communications
Kengo Takahashi, Tomoaki Nagai, Shuhei Chiba, Keiko Nakayama, Kensaku Mizuno
Primary cilia are antenna-like sensory organelles extending from the surface of many cell types that play critical roles in tissue development and homeostasis. Here, we examined the effect of nutrient status on primary cilium formation. Glucose deprivation significantly increased the number of ciliated cells under both serum-fed and -starved conditions. Glucose deprivation-induced ciliogenesis was suppressed by overexpression of Rheb, an activator of the mammalian target of rapamycin complex-1 (mTORC1). Inactivating mTORC1 by rapamycin treatment or Raptor knockdown significantly promoted ciliogenesis...
January 8, 2018: Journal of Cell Science
Hui Peng, Atsuo Kasada, Masaya Ueno, Takayuki Hoshii, Yuko Tadokoro, Naho Nomura, Chiaki Ito, Yusuke Takase, Ha Thi Vu, Masahiko Kobayashi, Bo Xiao, Paul F Worley, Atsushi Hirao
The mammalian target of rapamycin (mTOR) complex 1 (mTORC1) senses a cell's energy status and environmental levels of nutrients and growth factors. In response, mTORC1 mediates signaling that controls protein translation and cellular metabolism. Although mTORC1 plays a critical role in hematopoiesis, it remains unclear which upstream stimuli regulate mTORC1 activity in the context of hematopoietic stem cells (HSC) maintenance in vivo. In this study, we investigated the function of Rheb, a critical regulator of mTORC1 activity controlled by the PI3K-AKT-TSC axis, both in HSC maintenance in mice at steady-state and in HSC-derived hematopoiesis post-transplantation...
January 1, 2018: Biochemical and Biophysical Research Communications
Persaud Avinash, Cormerais Yann, Pouyssegur Jacques, Rotin Daniela
mTORC1 plays a critical role in protein synthesis and cell proliferation and growth. It is activated by growth factors and amino acids, including essential amino acid (EAA), such as Leu; Leu enters cells via the Leu transporter LAT1-4F2hc and potentially via endocytosis. Here we investigated the contribution of the different routes of Leu entry into cells to mTORC1 activation using pharmacological inhibitors and cells that lack LAT1 or dynamin1/2/3. Our results show that LAT1 is the major route of Leu entry into cells and mTORC1 activation (∼70%), while dynamin-dependent endocytosis and macropinocytosis contribute minimally to both (5-15%)...
November 17, 2017: Journal of Cell Science
Mei Yu, Yuhong Chen, Hu Zeng, Yongwei Zheng, Guoping Fu, Wen Zhu, Ulrich Broeckel, Praful Aggarwal, Amy Turner, Geoffrey Neale, Cliff Guy, Nan Zhu, Hongbo Chi, Renren Wen, Demin Wang
The precise molecular mechanism underlying the regulation of early B cell lymphopoiesis is unclear. The PLCγ signaling pathway is critical for antigen receptor-mediated lymphocyte activation, but its function in cytokine signaling is unknown. Here we show that PLCγ1/PLCγ2 double deficiency in mice blocks early B cell development at the pre-pro-B cell stage and renders B cell progenitors unresponsive to IL-7. PLCγ pathway inhibition blocks IL-7-induced activation of mTOR, but not Stat5. The PLCγ pathway activates mTOR through the DAG/PKC signaling branch, independent of the conventional Akt/TSC/Rheb signaling axis...
November 13, 2017: Nature Communications
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"