scholarly journals A Protein with Similarity to PTEN Regulates Aggregation Territory Size by Decreasing Cyclic AMP Pulse Size during Dictyostelium discoideum Development

2008 ◽  
Vol 7 (10) ◽  
pp. 1758-1770 ◽  
Author(s):  
Yitai Tang ◽  
Richard H. Gomer
Keyword(s):  
Cyclic Amp ◽  
Group Size ◽  
Actin Polymerization ◽  
Insertional Mutagenesis ◽  
Territory Size ◽  
Camp Phosphodiesterase ◽  
Phosphatase And Tensin Homolog ◽  
Akt Activation ◽  
Tensin Homolog ◽  
Eukaryotic Organisms

ABSTRACT An interesting but largely unanswered biological question is how eukaryotic organisms regulate the size of multicellular tissues. During development, a lawn of Dictyostelium cells breaks up into territories, and within the territories the cells aggregate in dendritic streams to form groups of ∼20,000 cells. Using random insertional mutagenesis to search for genes involved in group size regulation, we found that an insertion in the cnrN gene affects group size. Cells lacking CnrN (cnrN −) form abnormally small groups, which can be rescued by the expression of exogenous CnrN. Relayed pulses of extracellular cyclic AMP (cAMP) direct cells to aggregate by chemotaxis to form aggregation territories and streams. cnrN − cells overaccumulate cAMP during development and form small territories. Decreasing the cAMP pulse size by treating cnrN − cells with cAMP phosphodiesterase or starving cnrN − cells at a low density rescues the small-territory phenotype. The predicted CnrN sequence has similarity to phosphatase and tensin homolog (PTEN), which in Dictyostelium inhibits cAMP-stimulated phosphatidylinositol 3-kinase signaling pathways. CnrN inhibits cAMP-stimulated phosphatidylinositol 3,4,5-trisphosphate accumulation, Akt activation, actin polymerization, and cAMP production. Our results suggest that CnrN is a protein with some similarities to PTEN and that it regulates cAMP signal transduction to regulate territory size.

scholarly journals Dysregulation of MITF Leads to Transformation in MC1R-Defective Melanocytes

Cancers ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1719
Author(s):  
Timothy J. Lavelle ◽  
Tine Norman Alver ◽  
Karen-Marie Heintz ◽  
Patrik Wernhoff ◽  
Vegard Nygaard ◽  
...  
Keyword(s):  
Cell Line ◽  
Cell Transformation ◽  
Soft Agar ◽  
Transformation Process ◽  
Loss Of Function ◽  
Phosphatase And Tensin Homolog ◽  
Akt Activation ◽  
Transcriptional Reprogramming ◽  
Tensin Homolog ◽  
Tyrosine Receptor Kinase

The MC1R/cAMP/MITF pathway is a key determinant for growth, differentiation, and survival of melanocytes and melanoma. MITF-M is the melanocyte-specific isoform of Microphthalmia-associated Transcription Factor (MITF) in human melanoma. Here we use two melanocyte cell lines to show that forced expression of hemagglutinin (HA) -tagged MITF-M through lentiviral transduction represents an oncogenic insult leading to consistent cell transformation of the immortalized melanocyte cell line Hermes 4C, being a melanocortin-1 receptor (MC1R) compound heterozygote, while not causing transformation of the MC1R wild type cell line Hermes 3C. The transformed HA-tagged MITF-M transduced Hermes 4C cells form colonies in soft agar and tumors in mice. Further, Hermes 4C cells display increased MITF chromatin binding, and transcriptional reprogramming consistent with an invasive melanoma phenotype. Mechanistically, forced expression of MITF-M drives the upregulation of the AXL tyrosine receptor kinase (AXL), with concomitant downregulation of phosphatase and tensin homolog (PTEN), leading to increased activation of the PI3K/AKT pathway. Treatment with AXL inhibitors reduces growth of the transformed cells by reverting AKT activation. In conclusion, we present a model system of melanoma development, driven by MITF-M in the context of MC1R loss of function, and independent of UV exposure. This model provides a basis for further studies of critical changes in the melanocyte transformation process.

scholarly journals Phosphatase and Tensin Homolog Deleted on Chromosome 10 (PTEN) Inhibition by 4-Hydroxynonenal Leads to Increased Akt Activation in Hepatocytes

2011 ◽  
Vol 79 (6) ◽  
pp. 941-952 ◽  
Author(s):  
Colin T. Shearn ◽  
Rebecca L. Smathers ◽  
Benjamin J. Stewart ◽  
Kristofer S. Fritz ◽  
James J. Galligan ◽  
...  
Keyword(s):  
Chromosome 10 ◽  
Phosphatase And Tensin Homolog ◽  
Akt Activation ◽  
Tensin Homolog ◽  
Pten Inhibition

scholarly journals High Throughput Screen Identifies the DNMT1 (DNA Methyltransferase-1) Inhibitor, 5-Azacytidine, as a Potent Inducer of PTEN (Phosphatase and Tensin Homolog)

2020 ◽  
Vol 40 (8) ◽  
pp. 1854-1869
Author(s):  
Keith A. Strand ◽  
Sizhao Lu ◽  
Marie F. Mutryn ◽  
Linfeng Li ◽  
Qiong Zhou ◽  
...  
Keyword(s):  
Protein Expression ◽  
High Throughput ◽  
Knockout Mice ◽  
Vascular Remodeling ◽  
Dna Methyltransferase ◽  
Dna Methyltransferase 1 ◽  
Protective Effects ◽  
High Throughput Screen ◽  
Phosphatase And Tensin Homolog ◽  
Tensin Homolog

Objective: Our recent work demonstrates that PTEN (phosphatase and tensin homolog) is an important regulator of smooth muscle cell (SMC) phenotype. SMC-specific PTEN deletion promotes spontaneous vascular remodeling and PTEN loss correlates with increased atherosclerotic lesion severity in human coronary arteries. In mice, PTEN overexpression reduces plaque area and preserves SMC contractile protein expression in atherosclerosis and blunts Ang II (angiotensin II)-induced pathological vascular remodeling, suggesting that pharmacological PTEN upregulation could be a novel therapeutic approach to treat vascular disease. Approach and Results: To identify novel PTEN activators, we conducted a high-throughput screen using a fluorescence based PTEN promoter-reporter assay. After screening ≈3400 compounds, 11 hit compounds were chosen based on level of activity and mechanism of action. Following in vitro confirmation, we focused on 5-azacytidine, a DNMT1 (DNA methyltransferase-1) inhibitor, for further analysis. In addition to PTEN upregulation, 5-azacytidine treatment increased expression of genes associated with a differentiated SMC phenotype. 5-Azacytidine treatment also maintained contractile gene expression and reduced inflammatory cytokine expression after PDGF (platelet-derived growth factor) stimulation, suggesting 5-azacytidine blocks PDGF-induced SMC de-differentiation. However, these protective effects were lost in PTEN-deficient SMCs. These findings were confirmed in vivo using carotid ligation in SMC-specific PTEN knockout mice treated with 5-azacytidine. In wild type controls, 5-azacytidine reduced neointimal formation and inflammation while maintaining contractile protein expression. In contrast, 5-azacytidine was ineffective in PTEN knockout mice, indicating that the protective effects of 5-azacytidine are mediated through SMC PTEN upregulation. Conclusions: Our data indicates 5-azacytidine upregulates PTEN expression in SMCs, promoting maintenance of SMC differentiation and reducing pathological vascular remodeling in a PTEN-dependent manner.

miR-139-5p promotes neovascularization in diabetic retinopathy by regulating the phosphatase and tensin homolog

2021 ◽  
Vol 44 (2) ◽  
pp. 205-218
Author(s):  
Zhongwei Zhang ◽  
Caiping Song ◽  
Tao Wang ◽  
Lei Sun ◽  
Ling Qin ◽  
...  
Keyword(s):  
Diabetic Retinopathy ◽  
Phosphatase And Tensin Homolog ◽  
Tensin Homolog

scholarly journals Cyclic AMP responses are suppressed in mammalian cells expressing the yeast low Km cAMP-phosphodiesterase gene.

1990 ◽  
Vol 265 (10) ◽  
pp. 5840-5846
Author(s):  
M M Van Lookeren Campagne ◽  
E Wu ◽  
R D Fleischmann ◽  
M M Gottesman ◽  
K W Chason ◽  
...  
Keyword(s):  
Cyclic Amp ◽  
Mammalian Cells ◽  
Camp Phosphodiesterase

scholarly journals The Mitochondrial Kinase PINK1 in Diabetic Kidney Disease

2021 ◽  
Vol 22 (4) ◽  
pp. 1525
Author(s):  
Chunling Huang ◽  
Ji Bian ◽  
Qinghua Cao ◽  
Xin-Ming Chen ◽  
Carol A. Pollock
Keyword(s):  
Kidney Disease ◽  
Diabetic Kidney Disease ◽  
Kidney Diseases ◽  
Mitochondrial Protein ◽  
Physiological Role ◽  
Close Link ◽  
Promising Alternative ◽  
Diabetic Kidney ◽  
Phosphatase And Tensin Homolog ◽  
Tensin Homolog

Mitochondria are critical organelles that play a key role in cellular metabolism, survival, and homeostasis. Mitochondrial dysfunction has been implicated in the pathogenesis of diabetic kidney disease. The function of mitochondria is critically regulated by several mitochondrial protein kinases, including the phosphatase and tensin homolog (PTEN)-induced kinase 1 (PINK1). The focus of PINK1 research has been centered on neuronal diseases. Recent studies have revealed a close link between PINK1 and many other diseases including kidney diseases. This review will provide a concise summary of PINK1 and its regulation of mitochondrial function in health and disease. The physiological role of PINK1 in the major cells involved in diabetic kidney disease including proximal tubular cells and podocytes will also be summarized. Collectively, these studies suggested that targeting PINK1 may offer a promising alternative for the treatment of diabetic kidney disease.

scholarly journals Hepatic HuR protects against the pathogenesis of non-alcoholic fatty liver disease by targeting PTEN

2021 ◽  
Vol 12 (3) ◽  
Author(s):  
Mi Tian ◽  
Jingjing Wang ◽  
Shangming Liu ◽  
Xinyun Li ◽  
Jingyuan Li ◽  
...  
Keyword(s):  
Glucose Metabolism ◽  
Hepatic Steatosis ◽  
Chow Diet ◽  
Alcoholic Fatty Liver ◽  
Phosphatase And Tensin Homolog ◽  
Tensin Homolog ◽  
Pten Mrna ◽  
Normal Chow ◽  
Mice Liver

AbstractThe liver plays an important role in lipid and glucose metabolism. Here, we show the role of human antigen R (HuR), an RNA regulator protein, in hepatocyte steatosis and glucose metabolism. We investigated the level of HuR in the liver of mice fed a normal chow diet (NCD) and a high-fat diet (HFD). HuR was downregulated in the livers of HFD-fed mice. Liver-specific HuR knockout (HuRLKO) mice showed exacerbated HFD-induced hepatic steatosis along with enhanced glucose tolerance as compared with control mice. Mechanistically, HuR could bind to the adenylate uridylate-rich elements of phosphatase and tensin homolog deleted on the chromosome 10 (PTEN) mRNA 3′ untranslated region, resulting in the increased stability of Pten mRNA; genetic knockdown of HuR decreased the expression of PTEN. Finally, lentiviral overexpression of PTEN alleviated the development of hepatic steatosis in HuRLKO mice in vivo. Overall, HuR regulates lipid and glucose metabolism by targeting PTEN.

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