scholarly journals An Emerging Role for IQGAP1 in Regulating Protein Traffic

2010 ◽  
Vol 10 ◽  
pp. 944-953 ◽  
Author(s):  
Mahasin Osman
Keyword(s):  
Cell Growth ◽  
Specific Inhibitor ◽  
Membrane Traffic ◽  
Mtor Pathway ◽  
Human Diseases ◽  
Multifunctional Protein ◽  
Intracellular Traffic ◽  
Human Cancers ◽  
C Terminus ◽  
Wide Range

IQGAP1, an effector of CDC42p GTPase, is a widely conserved, multifunctional protein that bundles F-actin through its N-terminus and binds microtubules through its C-terminus to modulate the cell architecture. It has emerged as a potential oncogene associated with diverse human cancers. Therefore, IQGAP1 has been heavily investigated; regardless, its precise cellular function remains unclear. Work from yeast suggests that IQGAP1 plays an important role in directed cell growth, which is a conserved feature crucial to morphogenesis, division axis, and body plan determination. New evidence suggests a conserved role for IQGAP1 in protein synthesis and membrane traffic, which may help to explain the diversity of its cellular functions. Membrane traffic mediates infections by intracellular pathogens and a range of degenerative human diseases arise from dysfunctions in intracellular traffic; thus, elucidating the mechanisms of cellular traffic will be important in order to understand the basis of a wide range of inherited and acquired human diseases. Recent evidence suggests that IQGAP1 plays its role in cell growth through regulating the conserved mTOR pathway. The mTOR signaling cascade has been implicated in membrane traffic and is activated in nearly all human cancers, but clinical response to the mTOR-specific inhibitor rapamycin has been disappointing. Thus, understanding the regulators of this pathway will be crucial in order to identify predictors of rapamycin sensitivity. In this review, I discuss emerging evidence that supports a potential role of IQGAP1 in regulating membrane traffic via regulating the mTOR pathway.

scholarly journals mTOR Signaling at the Crossroad between Metazoan Regeneration and Human Diseases

2020 ◽  
Vol 21 (8) ◽  
pp. 2718 ◽  
Author(s):  
Yasmine Lund-Ricard ◽  
Patrick Cormier ◽  
Julia Morales ◽  
Agnès Boutet
Keyword(s):  
Evolutionary Biology ◽  
Mammalian Target Of Rapamycin ◽  
Mtor Pathway ◽  
Mtor Signaling ◽  
Human Diseases ◽  
Whole Body ◽  
Body Parts ◽  
Animal Kingdom ◽  
Structure Damage ◽  
Wide Range

A major challenge in medical research resides in controlling the molecular processes of tissue regeneration, as organ and structure damage are central to several human diseases. A survey of the literature reveals that mTOR (mechanistic/mammalian target of rapamycin) is involved in a wide range of regeneration mechanisms in the animal kingdom. More particularly, cellular processes such as growth, proliferation, and differentiation are controlled by mTOR. In addition, autophagy, stem cell maintenance or the newly described intermediate quiescence state, Galert, imply upstream monitoring by the mTOR pathway. In this review, we report the role of mTOR signaling in reparative regenerations in different tissues and body parts (e.g., axon, skeletal muscle, liver, epithelia, appendages, kidney, and whole-body), and highlight how the mTOR kinase can be viewed as a therapeutic target to boost organ repair. Studies in this area have focused on modulating the mTOR pathway in various animal models to elucidate its contribution to regeneration. The diversity of metazoan species used to identify the implication of this pathway might then serve applied medicine (in better understanding what is required for efficient treatments in human diseases) but also evolutionary biology. Indeed, species-specific differences in mTOR modulation can contain the keys to appreciate why certain regeneration processes have been lost or conserved in the animal kingdom.

scholarly journals In vivo identification of GTPase interactors by mitochondrial relocalization and proximity biotinylation

2019 ◽  
Author(s):  
Alison Gillingham ◽  
Jessie Bertram ◽  
Farida Begum ◽  
Sean Munro
Keyword(s):  
Cell Growth ◽  
Membrane Traffic ◽  
Effector Proteins ◽  
Rab Gtpases ◽  
Wide Range ◽  
Ras Superfamily ◽  
Ras Family ◽  
Regulate Cell Growth

AbstractThe GTPases of the Ras superfamily regulate cell growth, membrane traffic and the cytoskeleton, and a wide range of diseases are caused by mutations in particular members. They function as switchable landmarks with the active GTP-bound form recruiting to the membrane a specific set of effector proteins. The GTPases are precisely controlled by regulators that promote acquisition of GTP (GEFs) or its hydrolysis to GDP (GAPs). We report here MitoID, a method for identifying effectors and regulators by performing in vivo proximity biotinylation with mitochondrially-localized forms of the GTPases. Applying this to 11 human Rab GTPases identified many known effectors and GAPs, as well as putative novel effectors, with examples of the latter validated for Rab2, Rab5 and Rab9. MitoID can also efficiently identify effectors and GAPs of Rho and Ras family GTPases such as Cdc42, RhoA, Rheb, and N-Ras, and can identify GEFs by use of GDP-bound forms.

scholarly journals In vivo identification of GTPase interactors by mitochondrial relocalization and proximity biotinylation

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Alison K Gillingham ◽  
Jessie Bertram ◽  
Farida Begum ◽  
Sean Munro
Keyword(s):  
Cell Growth ◽  
Membrane Traffic ◽  
Effector Proteins ◽  
Rab Gtpases ◽  
Wide Range ◽  
Ras Superfamily ◽  
Ras Family ◽  
Regulate Cell Growth

The GTPases of the Ras superfamily regulate cell growth, membrane traffic and the cytoskeleton, and a wide range of diseases are caused by mutations in particular members. They function as switchable landmarks with the active GTP-bound form recruiting to the membrane a specific set of effector proteins. The GTPases are precisely controlled by regulators that promote acquisition of GTP (GEFs) or its hydrolysis to GDP (GAPs). We report here MitoID, a method for identifying effectors and regulators by performing in vivo proximity biotinylation with mitochondrially-localized forms of the GTPases. Applying this to 11 human Rab GTPases identified many known effectors and GAPs, as well as putative novel effectors, with examples of the latter validated for Rab2, Rab5, Rab9 and Rab11. MitoID can also efficiently identify effectors and GAPs of Rho and Ras family GTPases such as Cdc42, RhoA, Rheb, and N-Ras, and can identify GEFs by use of GDP-bound forms.

scholarly journals Bnip3 Mediates the Hypoxia-induced Inhibition on Mammalian Target of Rapamycin by Interacting with Rheb

2007 ◽  
Vol 282 (49) ◽  
pp. 35803-35813 ◽  
Author(s):  
Yong Li ◽  
Yian Wang ◽  
Eunjung Kim ◽  
Peter Beemiller ◽  
Cun-Yu Wang ◽  
...  
Keyword(s):  
Cell Growth ◽  
Energy Levels ◽  
Mammalian Target Of Rapamycin ◽  
Small Gtpase ◽  
Mtor Pathway ◽  
Target Of Rapamycin ◽  
Intracellular Signals ◽  
Central Controller ◽  
Wide Range

The mammalian target of rapamycin (mTOR) is a central controller of cell growth, and it regulates translation, cell size, cell viability, and cell morphology. mTOR integrates a wide range of extracellular and intracellular signals, including growth factors, nutrients, energy levels, and stress conditions. Rheb, a Ras-related small GTPase, is a key upstream activator of mTOR. In this study, we found that Bnip3, a hypoxia-inducible Bcl-2 homology 3 domain-containing protein, directly binds Rheb and inhibits the mTOR pathway. Bnip3 decreases Rheb GTP levels in a manner depending on the binding to Rheb and the presence of the N-terminal domain. Both knockdown and overexpression experiments show that Bnip3 plays an important role in mTOR inactivation in response to hypoxia. Moreover, Bnip3 inhibits cell growth in vivo by suppressing the mTOR pathway. These observations demonstrate that Bnip3 mediates the inhibition of the mTOR pathway in response to hypoxia.

Oncogenic LncRNA CASC9 in Cancer Progression

2020 ◽  
Vol 26 ◽  
Author(s):  
Yuying Qi ◽  
Chaoying Song ◽  
Jiali Zhang ◽  
Chong Guo ◽  
Chengfu Yuan
Keyword(s):  
Cell Proliferation ◽  
Drug Resistance ◽  
Cell Growth ◽  
Cancer Cells ◽  
Therapeutic Potential ◽  
Squamous Metaplasia ◽  
Neoplastic Transformation ◽  
Over Expression ◽  
Human Cancers ◽  
Current Review

Background: Long non-coding RNA (LncRNAs), with the length over 200 nucleotides, originate from intergenic, antisense, or promoter-proximal regions, is a large family of RNAs that lack coding capacity. Emerging evidences illustrated that LncRNAs played significant roles in a variety of cellular functions and biological processes in profuse human diseases, especially in cancers. Cancer susceptibility candidate 9 (CASC9), as a member of the LncRNAs group, was firstly found its oncogenic function in esophageal cancer. In following recent studies, a growing amount of human malignancies are verified to be correlated with CASC9, most of which are derived from the squamous epithelium tissue. This present review attempts to highlight the latest insights into the expression, functional roles, and molecular mechanisms of CASC9 in different human malignancies. Methods: In this review, the latest findings related to the pathophysiological processes of CASC9 in human cancers were summarized and analyzed, the associated studies were collected in systematically retrieval of PubMed used lncRNA and CASA9 as keywords. Results: CASC9 expression is identified to be aberrantly elevated in a variety of malignancies. The over-expression of CASC9 has been suggested to accelerate cell proliferation, migration, cell growth and drug resistance of cancer cells, while depress cell apoptosis, revealing its role as an oncogene. Moreover, the current review demonstrated CASC9 closely relates to neoplastic transformation of squamous epithelial cells and squamous metaplasia in non-squamous epithelial tissues. Finally, we discuss the limitations and tremendous diagnostic/therapeutic potential of CASC9 in various human cancers. Results: CASC9 expression is identified to be aberrantly elevated in a variety of malignancies. The over-expression of CASC9 has been suggested to accelerate cell proliferation, migration, cell growth and drug resistance of cancer cells, while depress cell apoptosis, revealing its role as an oncogene. Moreover, the current review demonstrated CASC9 closely relates to neoplastic transformation of squamous epithelial cells and squamous metaplasia in non-squamous epithelial tissues. Finally, we discuss the limitations and tremendous diagnostic/therapeutic potential of CASC9 in various human cancers. Conclusion: Long non-coding RNACASC9 likely served as useful disease biomarkers or therapy targets that could effectively apply in treatment of different kinds of cancers.

scholarly journals Apoptotic Effects of Xanthium strumarium via PI3K/AKT/mTOR Pathway in Hepatocellular Carcinoma

2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
Juyoung Kim ◽  
Kyung Hee Jung ◽  
Hyung Won Ryu ◽  
Doo-Young Kim ◽  
Sei-Ryang Oh ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Cell Growth ◽  
Caspase 3 ◽  
Mtor Pathway ◽  
Terminal Deoxynucleotidyl Transferase ◽  
Mechanistic Study ◽  
Migration And Invasion ◽  
Xanthium Strumarium ◽  
Apoptotic Effects ◽  
Hcc Cells

Xanthium strumarium (XS) has been traditionally used as a medicinal herb for treating inflammatory diseases, such as appendicitis, chronic bronchitis, rheumatism, and rhinitis. In this study, we yielded ethanol extracts from XS and investigated whether they could inhibit the progression of hepatocellular carcinoma (HCC) and its underlying mechanism. The XS-5 and XS-6 extracts dose-dependently inhibited the growth and proliferation in HCC cell lines. The apoptotic effects of them were observed via increased levels of cleaved caspase-3 and cleaved PARP, as well as elevated numbers of terminal deoxynucleotidyl transferase-mediated dUTP-biotin end labeling- (TUNEL-) positive apoptotic cells. They also decreased XIAP and Mcl-1 expression via loss of mitochondrial membrane potential. Additionally, they inhibited the invasion and migration of HCC cells. In an ex vivo model, the extracts significantly inhibited tumor cell growth and induced apoptosis by increasing the expression of the cleaved caspase-3. A mechanistic study revealed that they effectively suppressed PI3K/AKT/mTOR signaling pathways in HCC cells. Taken together, our findings demonstrate that they could efficiently not only induce apoptosis but also inhibit cell growth, migration, and invasion of human HCC cells by blocking the PI3K/AKT/mTOR pathway. We suggest XS-5 and XS-6 as novel natural anti-HCC agents.

scholarly journals TAMI-38. CYSTEINE-PROMOTING COMPOUNDS INDUCE MITOCHONDRIAL TOXICITY IN GLIOBLASTOMA THROUGH ALTERED PYRUVATE AND SERINE METABOLISM

2020 ◽  
Vol 22 (Supplement_2) ◽  
pp. ii221-ii221
Author(s):  
Evan Noch ◽  
Laura Palma ◽  
Isaiah Yim ◽  
Bhavneet Binder ◽  
Elisa Benedetti ◽  
...  
Keyword(s):  
Amino Acid ◽  
Cell Growth ◽  
Growth Inhibition ◽  
Glucose Deprivation ◽  
Tumor Metabolism ◽  
Metabolic Phenotype ◽  
Low Grade ◽  
Mitochondrial Toxicity ◽  
Human Cancers ◽  
Pathway Gene

Abstract Glioblastoma (GBM) remains a poorly treatable disease with high mortality. Tumor metabolism in GBM is a critical mechanism responsible for accelerated growth because of upregulation of glucose, amino acid, and fatty acid utilization. However, little is known about the metabolic alterations that are specific to GBM and that are targetable with FDA-approved compounds. To investigate tumor metabolism signatures unique to GBM, we interrogated the TCGA and a cancer metabolite database for alterations in glucose and amino acid signatures in GBM relative to other human cancers and relative to low-grade glioma. From these analyses, we found that GBM exhibits the highest levels of cysteine and methionine pathway gene expression of 32 human cancers and that GBM exhibits high levels of cysteine-related metabolites compared to low-grade gliomas. To study the role of cysteine in GBM pathogenesis, we treated patient-derived GBM cells with a variety of FDA-approved cyst(e)ine-promoting compounds in vitro, including N-acetylcysteine (NAC) and the cephalosporin antibiotic, Ceftriaxone (CTX), which induces cystine import through System Xc transporter upregulation. Cysteine-promoting compounds, including NAC and CTX, inhibit growth of GBM cells, which is exacerbated by glucose deprivation. This growth inhibition is associated with reduced mitochondrial metabolism, manifest by reduction in ATP, NADPH/NADP+ ratio, mitochondrial membrane potential, and oxygen consumption rate. Metabolic tracing experiments with 13C6-glucose demonstrate that L-serine is rapidly depleted in GBM cells upon treatment with NAC and CTX, and exogenous serine rescues NAC- and CTX-mediated cell growth inhibition. In addition, these compounds reduce GBM mitochondrial pyruvate transport. We show that cysteine-promoting compounds reduce cell growth and induce mitochondrial toxicity in GBM, which may be due to rapid serine depletion and reduced mitochondrial pyruvate transport. This metabolic phenotype is exacerbated by glucose deprivation. This pathway is targetable with FDA-approved cysteine-promoting compounds and could synergize with glucose-lowering treatments, including the ketogenic diet, for GBM.

scholarly journals Arginine Methyltransferase PRMT1 Regulates p53 Activity in Breast Cancer

Life ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 789
Author(s):  
Li-Ming Liu ◽  
Qiang Tang ◽  
Xin Hu ◽  
Jing-Jing Zhao ◽  
Yuan Zhang ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cell Growth ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
Asymmetric Dimethylarginine ◽  
Human Cancer ◽  
Specific Inhibitor ◽  
Dependent Manner ◽  
Breast Tumorigenesis ◽  
Stress Signals

The protein p53 is one of the most important tumor suppressors, responding to a variety of stress signals. Mutations in p53 occur in about half of human cancer cases, and dysregulation of the p53 function by epigenetic modifiers and modifications is prevalent in a large proportion of the remainder. PRMT1 is the main enzyme responsible for the generation of asymmetric-dimethylarginine, whose upregulation or aberrant splicing has been observed in many types of malignancies. Here, we demonstrate that p53 function is regulated by PRMT1 in breast cancer cells. PRMT1 knockdown activated the p53 signal pathway and induced cell growth-arrest and senescence. PRMT1 could directly bind to p53 and inhibit the transcriptional activity of p53 in an enzymatically dependent manner, resulting in a decrease in the expression levels of several key downstream targets of the p53 pathway. We were able to detect p53 asymmetric-dimethylarginine signals in breast cancer cells and breast cancer tissues from patients, and the signals could be significantly weakened by silencing of PRMT1 with shRNA, or inhibiting PRMT1 activity with a specific inhibitor. Furthermore, PRMT1 inhibitors significantly impeded cell growth and promoted cellular senescence in breast cancer cells and primary tumor cells. These results indicate an important role of PRMT1 in the regulation of p53 function in breast tumorigenesis.

scholarly journals Adenine Addition Restores Cell Viability and Butanol Production in Clostridium saccharoperbutylacetonicum N1-4 (ATCC 13564) Cultivated at 37°C

2017 ◽  
Vol 83 (7) ◽  
Author(s):  
Keiji Kiyoshi ◽  
Sohei Kawashima ◽  
Kosuke Nobuki ◽  
Toshimori Kadokura ◽  
Atsumi Nakazato ◽  
...  
Keyword(s):  
Cell Growth ◽  
Cell Viability ◽  
Spore Formation ◽  
Butanol Production ◽  
Metabolomic Analysis ◽  
Primary Metabolites ◽  
Content Type ◽  
Atp Levels ◽  
Wide Range ◽  
Multiple Primary

ABSTRACT We have developed butanol-producing consolidated bioprocessing from cellulosic substrates through coculture of cellulolytic clostridia and butanol-producing Clostridium saccharoperbutylacetonicum strain N1-4. However, the butanol fermentation by strain N1-4 (which has an optimal growth temperature of 30°C) is sensitive to the higher cultivation temperature of 37°C; the nature of this deleterious effect remains unclear. Comparison of the intracellular metabolites of strain N1-4 cultivated at 30°C and 37°C revealed decreased levels of multiple primary metabolites (notably including nucleic acids and cofactors) during growth at the higher temperature. Supplementation of the culture medium with 250 mg/liter adenine enhanced both cell growth (with the optical density at 600 nm increasing from 4.3 to 10.2) and butanol production (increasing from 3.9 g/liter to 9.6 g/liter) at 37°C, compared to those obtained without adenine supplementation, such that the supplemented 37°C culture exhibited growth and butanol production approaching those observed at 30°C in the absence of adenine supplementation. These improved properties were based on the maintenance of cell viability. We further showed that adenine supplementation enhanced cell viability during growth at 37°C by maintaining ATP levels and inhibiting spore formation. This work represents the first demonstration (to our knowledge) of the importance of adenine-related metabolism for clostridial butanol production, suggesting a new means of enhancing target pathways based on metabolite levels. IMPORTANCE Metabolomic analysis revealed decreased levels of multiple primary metabolites during growth at 37°C, compared to 30°C, in C. saccharoperbutylacetonicum strain N1-4. We found that adenine supplementation restored the cell growth and butanol production of strain N1-4 at 37°C. The effects of adenine supplementation reflected the maintenance of cell viability originating from the maintenance of ATP levels and the inhibition of spore formation. Thus, our metabolomic analysis identified the depleted metabolites that were required to maintain cell viability. Our strategy, which is expected to be applicable to a wide range of organisms, permits the identification of the limiting metabolic pathway, which can serve as a new target for molecular breeding. The other novel finding of this work is that adenine supplementation inhibits clostridial spore formation. The mechanism linking spore formation and metabolomic status in butanol-producing clostridia is expected to be the focus of further research.

scholarly journals A new lead to NLRP3 inhibition

2017 ◽  
Vol 214 (11) ◽  
pp. 3147-3149 ◽  
Author(s):  
Mohamed Lamkanfi ◽  
Vishva M. Dixit
Keyword(s):  
Small Molecule ◽  
Small Molecule Inhibitor ◽  
Therapeutic Benefit ◽  
Human Diseases ◽  
Molecule Inhibitor ◽  
Wide Range ◽  
Potential Therapeutic Benefit

The discovery of a small molecule inhibitor that targets the inflammasome sensor NLRP3 offers a new path for the development of selective inflammasome blockers with potential therapeutic benefit in a wide range of human diseases (in this issue, see Jiang et al., https://doi.org/10.1084/jem.20171419).

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