Fyn-Mediated Regulation of Protein Kinase A

Protein kinases are enzymes important for signal transduction in the regulation of cellular processes. The cAMP-dependent protein kinase A (PKA) has been previously reported to regulate the activity of the Src family kinase Fyn, an event important for cellular migration. This study aimed to characterize the reciprocal interaction, in which Fyn regulates PKA. In addition to our preliminary, unpublished findings that Fyn phosphorylates the PKA catalytic subunit at Y69 to increase its catalytic activity, we have shown through co-immunoprecipitation that Fyn physically associates with PKA in HEK293 cells. Quantitative mass spectrometry and subsequent biochemical validation shows that PKACα undergoes enhanced binding to a complex of centrosomal and Golgi-localized A-kinase anchoring proteins when Fyn is overexpressed, independent of Fyn kinase activity. Fyn was found in this complex, as well, implicating its involvement as an adaptor protein. Co-immunoprecipitation experiments with various Fyn alleles demonstrated the dispensability of the Fyn SH3 domain and the functioning SH2 domain in binding to PKACα. GST-fusion proteins containing either of these domains were also unable to enrich PKACα from HEK293 lysates. Fyn was found to bind PKACα independent of its association with the regulatory subunit, and preliminary data suggests that this interaction is direct through purified protein pulldown experiments. We hypothesize that this regulatory interaction activates PKA at the centrosome and Golgi apparatus, facilitating the potential phosphorylation of proximal substrates involved in cytoskeletal organization and mitotic processes

Evidence that TRPM8 is an androgen-dependent Ca2+ channel required for the survival of prostate cancer cells

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Curcumin inhibits activation of TRPM2 channels in rat hepatocytes

This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).Oxidative stress is a hallmark of many liver diseases including viral and drug-induced hepatitis, ischemia-reperfusion injury, and non-alcoholic steatohepatitis. One of the consequences of oxidative stress in the liver is deregulation of Ca(2+) homeostasis, resulting in a sustained elevation of the free cytosolic Ca(2+) concentration ([Ca(2+)]c) in hepatocytes, which leads to irreversible cellular damage. Recently it has been shown that liver damage induced by paracetamol and subsequent oxidative stress is, in large part, mediated by Ca(2+) entry through Transient Receptor Potential Melastatin 2 (TRPM2) channels. Involvement of TRPM2 channels in hepatocellular damage induced by oxidative stress makes TRPM2 a potential therapeutic target for treatment of a range of oxidative stress-related liver diseases. We report here the identification of curcumin ((1E,6E)-1,7-bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione), a natural plant-derived polyphenol in turmeric spice, as a novel inhibitor of TRPM2 channel. Presence of 5µM curcumin in the incubation medium prevented the H2O2- and paracetamol-induced [Ca(2+)]c rise in rat hepatocytes. Furthermore, in patch clamping experiments incubation of hepatocytes with curcumin inhibited activation of TRPM2 current by intracellular ADPR with IC50 of approximately 50nM. These findings enhance understanding of the actions of curcumin and suggest that the known hepatoprotective properties of curcumin are, at least in part, mediated through inhibition of TRPM2 channels

Mitochondria directly influence fertilisation outcome in the pig

The mitochondrion is explicitly involved in cytoplasmic regulation and is the cell's major generator of ATP. Our aim was to determine whether mitochondria alone could influence fertilisation outcome. In vitro, oocyte competence can be assessed through the presence of glucose-6-phosphate dehydrogenase (G6PD) as indicated by the dye, brilliant cresyl blue (BCB). Using porcine in vitro fertilisation (IVF), we have assessed oocyte maturation, cytoplasmic volume, fertilisation outcome, mitochondrial number as determined by mtDNA copy number, and whether mitochondria are uniformly distributed between blastomeres of each embryo. After staining with BCB, we observed a significant difference in cytoplasmic volume between BCB positive (BCB+) and BCB negative (BCB-) oocytes. There was also a significant difference in mtDNA copy number between fertilised and unfertilised oocytes and unequal mitochondrial segregation between blastomeres during early cleavage stages. Furthermore, we have supplemented BCB- oocytes with mitochondria from maternal relatives and observed a significant difference in fertilisation outcomes following both IVF and intracytoplasmic sperm injection (ICSI) between supplemented, sham-injected and non-treated BCB- oocytes. We have therefore demonstrated a relationship between oocyte maturity, cytoplasmic volume, and fertilisation outcome and mitochondrial content. These data suggest that mitochondrial number is important for fertilisation outcome and embryonic development. Furthermore, a mitochondrial pre-fertilisation threshold may ensure that, as mitochondria are diluted out during post-fertilisation cleavage, there are sufficient copies of mtDNA per blastomere to allow transmission of mtDNA to each cell of the post-implantation embryo after the initiation of mtDNA replication during the early postimplantation stages

Generating a high-resolution global magnetic model for oil and mineral exploration

This is the final contribution to the trilogy of articles on global potential-field data compilations. Getech's continental and national magnetic data compilations commenced in 1989 and were designed specifically for use in petroleum and mineral exploration. These studies complemented the continental-scale gravity-compilation studies that were the subject of the TLE “Meter Reader” contributions in March and May of this year. The success of these projects resulted from strategic partnerships, especially with Paterson, Grant and Watson Ltd. (PGW), and links to a wide range of national organizations. Early compilations covering the whole of Africa, South America, and China were followed by large-scale, small-scale, and national compilations and continue to this day with compilations of U. S. surveys. The projects spawned a range of technical developments, including approaches to remove survey-line noise, the integration of survey grids and disparate ship-track data, and the preservation of the longest-wavelength anomalies associated with the crustal magnetic field. The resulting global gravity and magnetic grids now form an invaluable resource for resource exploration

Unified Approach to Modeling and Simulation of Space Communication Networks and Systems

Network simulator software tools are often used to model the behaviors and interactions of applications, protocols, packets, and data links in terrestrial communication networks. Other software tools that model the physics, orbital dynamics, and RF characteristics of space systems have matured to allow for rapid, detailed analysis of space communication links. However, the absence of a unified toolset that integrates the two modeling approaches has encumbered the systems engineers tasked with the design, architecture, and analysis of complex space communication networks and systems. This paper presents the unified approach and describes the motivation, challenges, and our solution - the customization of the network simulator to integrate with astronautical analysis software tools for high-fidelity end-to-end simulation. Keywords space; communication; systems; networking; simulation; modeling; QualNet; STK; integration; space network

Emerging magnetic resonance imaging techniques and analysis methods in amyotrophic lateral sclerosis

Objective markers of disease sensitive to the clinical activity, symptomatic progression, and underlying substrates of neurodegeneration are highly coveted in amyotrophic lateral sclerosis in order to more eloquently stratify the highly heterogeneous phenotype and facilitate the discovery of effective disease modifying treatments for patients. Magnetic resonance imaging (MRI) is a promising, non-invasive biomarker candidate whose acquisition techniques and analysis methods are undergoing constant evolution in the pursuit of parameters which more closely represent biologically-applicable tissue changes. Neurite Orientation Dispersion and Density Imaging (NODDI; a form of diffusion imaging), and quantitative Magnetization Transfer Imaging (qMTi) are two such emerging modalities which have each broadened the understanding of other neurological disorders and have the potential to provide new insights into structural alterations initiated by the disease process in ALS. Furthermore, novel neuroimaging data analysis approaches such as Event-Based Modeling (EBM) may be able to circumvent the requirement for longitudinal scanning as a means to comprehend the dynamic stages of neurodegeneration . Combining these and other innovative imaging protocols with more sophisticated techniques to analyse ever-increasing datasets holds the exciting prospect of transforming understanding of the biological processes and temporal evolution of the ALS syndrome, and can only benefit from multicentre collaboration across the entire ALS research community

Predicting Liver Transplant Capacity Using Discrete Event Simulation

The number of liver transplants (LTs) performed in the US increased until 2006 but has since declined despite an ongoing increase in demand. This decline may be due in part to decreased donor liver quality and increasing discard of poor-quality livers. We constructed a discrete event simulation (DES) model informed by current donor characteristics to predict future LT trends through the year 2030. The data source for our model is the United Network for Organ Sharing database, which contains patient-level information on all organ transplants performed in the US. Previous analysis showed that liver discard is increasing and that discarded organs are more often from donors who are older, are obese, have diabetes, and donated after cardiac death. Given that the prevalence of these factors is increasing, the DES model quantifies the reduction in the number of LTs performed through 2030. In addition, the model estimatesthe total number of future donors needed to maintain the current volume of LTs and the effect of a hypothetical scenario of improved reperfusion technology.We also forecast the number of patients on the waiting list and compare this with the estimated number of LTs to illustrate the impact that decreased LTs will have on patients needing transplants. By altering assumptions about the future donor pool, this model can be used to develop policy interventions to prevent a further decline in this lifesaving therapy. To our knowledge, there are no similar predictive models of future LT use based on epidemiological trends

Paracentesis is Associated with Reduced Mortality in Patients Hospitalized with Cirrhosis and Ascites

Diagnostic paracentesis is recommended for patients with cirrhosis admitted to the hospital for ascites or encephalopathy. However, it is not known if clinicians in the United States adhere to this recommendation; a relationship between paracentesis and clinical outcome has not been reported. We analyzed a US database to determine the frequency of paracentesis and its association with mortality. Methods The 2009 Nationwide Inpatient Sample (which contains data from approximately 8 million hospital discharges each year) was used to identify patients with cirrhosis and ascites admitted with a primary diagnosis of ascites or encephalopathy. In-hospital mortality, length of stay, and hospital charges were compared for those who did and did not undergo paracentesis. Outcomes were compared for those who received an early paracentesis (within 1 day of admission) and those who received one later. Results Of 17,711 eligible admissions, only 61% underwent paracentesis. In-hospital mortality was reduced by 24% among patients who underwent paracentesis (6.5% vs 8.5%, adjusted odds ratio [OR], 0.55; 95% confidence interval [CI], 0.41–0.74). Most paracenteses (66%) occurred ≤1 day after admission. In-hospital mortality was lower among patients who received early paracentesis than those who received it later (5.7% vs 8.1%; P=.049), although this difference was not significant after adjustment for confounders (OR, 1.26; 95% CI, 0.78–2.02). Among patients who underwent paracentesis, the mean hospital stay was 14% longer, and hospital charges were 29% greater than for patients that did not receive the procedure. Conclusions Paracentesis is underused for patients admitted to the hospital with ascites; the procedure is associated with increased short-term survival. These data support practice guidelines derived from expert opinion. Studies are needed to identify barriers to guideline adherence