Amino Acids, Peptides, and Proteins Commons^™

Atf4 Is An Oxidative Stress–Inducible, Prodeath Transcription Factor In Neurons In Vitro And In Vivo, Philipp Lange, Juan Chavez, John T. Pinto, Giovanni Coppola, Chiao-Wang Sun, Tim Townes, Rajiv Ratan

NYMC Faculty Publications

Oxidative stress is pathogenic in neurological diseases, including stroke. The identity of oxidative stress-inducible transcription factors and their role in propagating the death cascade are not well known. In an in vitro model of oxidative stress, the expression of the bZip transcription factor activating transcription factor 4 (ATF4) was induced by glutathione depletion and localized to the promoter of a putative death gene in neurons. Germline deletion of ATF4 resulted in a profound reduction in oxidative stress-induced gene expression and resistance to oxidative death. In neurons, ATF4 modulates an early, upstream event in the death pathway, as resistance to oxidative …

Radiation-Induced Glutamate Transport Alterations In Neuron-Astrocyte Coupling, Martha Celia Sanchez

Loma Linda University Electronic Theses, Dissertations & Projects

Exposure of the central nervous system (CNS) to ionizing radiation is known to result in behavioral, cognitive, and motor deficits - effects similar to those seen in many neurodegenerative disorders. Neurons and astrocytes, two principal cell types in the brain, coexist as an interdependent metabolic unit via the neurotransmitter glutamate. Disruption of this metabolic coupling would have widespread effects within the CNS, therefore it is hypothesized that ionizing radiation impairs glutamate transport and metabolism, and increases oxidative stress, ultimately impairing neuron-astrocyte coupling. We propose to investigate the mechanism and determine the impetus for radiation-induced neurotoxicity by measuring the temporal sequence …

Monitoring Lys-TrnaLys Phosphatidylglycerol Transferase Activity, Michael Ibba

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

In some bacteria Lys-tRNA^Lys is used both in translation and for the specific addition of Lys to phosphatidylglycerol in the cytoplasmic membrane. This reaction is catalyzed by the membrane protein MprF, and the lysyl-phosphatidylglycerol formed contributes to the resistance of these bacteria to various cationic antibacterial molecules. Obtaining proteins and reconstituting an in vitro system mimicking membrane conditions is a major challenge to studying the function of membrane proteins, especially when labile substrates such as Lys-tRNA^Lys are required. Here we report methods to obtain a stable enriched membrane fraction containing MprF, and the techniques necessary to quantitatively monitor …

Adenylyl Cyclase Type 6 Overexpression Selectively Enhances Ss-Adrenergic And Prostacyclin Receptor Mediated Inhibition Of Rat Cardiac Fibroblast Function Due To Co-Localization In Lipid Rafts, Xiaoqiu Liu, Muthusamy Thangavel, Shu Qiang Sun, Joseph Kaminsky, Penden Mahautmr, Jeremiah Stitham, John Hwa, Rennolds S. Ostrom

Pharmacy Faculty Articles and Research

Cardiac fibroblasts produce and degrade extracellular matrix and are critical in regulating cardiac remodeling and hypertrophy. Fibroblasts are activated by factors such as transforming growth factor β and inhibited by agents that elevate 3′,5′-cyclic adenosine monophosphate (cAMP) levels. cAMP signal generation and response is known to be compartmentalized in many cell types in part through the colocalization of receptors and specific adenylyl cyclase isoforms in lipid rafts and caveolae. The present study sought to define the localization of key G protein-coupled receptors with adenylyl cyclase type 6 (AC6) in lipid rafts of rat cardiac fibroblasts and to determine if this …

Phenylalanyl-Trna Synthetase Editing Defects Result In Efficient Mistranslation Of Phenylalanine Codons As Tyrosine, Jiqiang Ling, Srujana S. Yadavalli, Michael Ibba

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Translational quality control is monitored at several steps, including substrate selection by aminoacyl-tRNA synthetases (aaRSs), and discrimination of aminoacyl-tRNAs by elongation factor Tu (EF-Tu) and the ribosome. Phenylalanyl-tRNA synthetase (PheRS) misactivates Tyr but is able to correct the mistake using a proofreading activity named editing. Previously we found that overproduction of editing-defective PheRS resulted in Tyr incorporation at Phe-encoded positions in vivo , although the misreading efficiency could not be estimated. This raised the question as to whether or not EF-Tu and the ribosome provide further proofreading mechanisms to prevent mistranslation of Phe codons by Tyr. Here we show that, …

An Aminoacyl-Trna Synthetase: Elongation Factor Complex For Substrate Channeling In Archaeal Translation, Corinne D. Hausmann, Mette Praetorius-Ibba, Michael Ibba

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Translation requires the specific attachment of amino acids to tRNAs by aminoacyl-tRNA synthetases (aaRSs) and the subsequent delivery of aminoacyl-tRNAs to the ribosome by elongation factor 1 alpha (EF-1α). Interactions between EF-1α and various aaRSs have been described in eukaryotes, but the role of these complexes remains unclear. To investigate possible interactions between EF-1α and other cellular components, a yeast two-hybrid screen was performed for the archaeon Methanothermobacter thermautotrophicus. EF-1α was found to form a stable complex with leucyl-tRNA synthetase (LeuRS; KD = 0.7 μ M). Complex formation had little effect on EF-1α activity, but increased the k_{cat …}

Stability Of Eukaryotic Elongation Factor One Alpha Protein In The Cell, Jennifer Watry

Honors Theses

Eukaryotic Elongation Factor One Alpha (eEF1A) is an abundant protein found in every cell of every organism and is involved in functions concerning protein synthesis and degradation, the cytoskeleton, and signaling. How these functions are regulated is not yet understood for this protein. Regulation of the protein may be controlled by transcription of the genes encoding the protein or the stability and modification of the protein. The goal of this project was to determine the stability of eEf1A proteins in Arabidopsis thaliana. Protein stability was determined by treating tissues with cycloheximide, an inhibitor of protein synthesis. Gel electrophoresis and …

Coupling Coherence Distinguishes Structure Sensitivity In Protein Electron Transfer, Tatiana Prytkova, Igor V. Kurnikov, David Beratan

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Quantum mechanical analysis of electron tunneling in nine thermally fluctuating cytochrome b562 derivatives reveals two distinct protein-mediated coupling limits. A structure-insensitive regime arises for redox partners coupled through dynamically averaged multiple-coupling pathways (in seven of the nine derivatives) where heme-edge coupling leads to the multiple-pathway regime. A structure-dependent limit governs redox partners coupled through a dominant pathway (in two of the nine derivatives) where axial-ligand coupling generates the single-pathway limit and slower rates. This two-regime paradigm provides a unified description of electron transfer rates in 26 ruthenium-modified heme and blue-copper proteins, as well as in numerous photosynthetic proteins.

Flavin Charge Transfer Transitions Assist Dna Photolyase Electron Transfer, Spiros S. Skourtis, Tatiana Prytkova, David Beratan

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

This contribution describes molecular dynamics, semi-empirical and ab-initio studies of the primary photo-induced electron transfer reaction in DNA photolyase. DNA photolyases are FADH−-containing proteins that repair UV-damaged DNA by photo-induced electron transfer. A DNA photolyase recognizes and binds to cyclobutatne pyrimidine dimer lesions of DNA. The protein repairs a bound lesion by transferring an electron to the lesion from FADH−, upon photo-excitation of FADH− with 350–450 nm light. We compute the lowest singlet excited states of FADH− in DNA photolyase using INDO/S configuration interaction, time-dependent density-functional, and time-dependent Hartree-Fock methods. The calculations identify the lowest singlet excited state of FADH− …

Functional Association Between Three Archaeal Aminoacyl-Trna Synthetases, Mette Praetorius-Ibba, Corinne D. Hausmann, Molly Paras, Theresa E. Rogers, Michael Ibba

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Aminoacyl-tRNA synthetases (aaRSs) are responsible for attaching amino acids to their cognate tRNAs during protein synthesis. In eukaryotes aaRSs are commonly found in multi-enzyme complexes, although the role of these complexes is still not completely clear. Associations between aaRSs have also been reported in archaea, including a complex between prolyl-(ProRS) and leucyl-tRNA synthetases (LeuRS) in Methanothermobacter thermautotrophicus that enhances tRNA^Pro aminoacylation. Yeast two-hybrid screens suggested that lysyl-tRNA synthetase (LysRS) also associates with LeuRS in M. thermautotrophicus. Co-purification experiments confirmed that LeuRS, LysRS, and ProRS associate in cell-free extracts. LeuRS bound LysRS and ProRS with a comparable K_{D …}

Gene Expression In The Mouse Placenta: Developmental And Stress Responses, Ciprian P. Gheorghe

Loma Linda University Electronic Theses, Dissertations & Projects

Successful placental development is crucial for optimal growth, maturation, and survival of the embryo/fetus. Placental failure and placental pathology contributes to both morbidity and mortality of the fetus. We sought to understand normal placental development and also placental responses to stress using oligonucleotide microarray technology. To examine genetic aspects of normal placental development, we investigated gene expression patterns in the murine placenta at embryonic day 10.5 (E10.5), E12.5, E15.5, and E17.5. Hypoxia has been identified as a major stressor in placental and fetal development. In order to comprehend more completely hypoxic stress responses we sought to measure gene expression changes …

Aspartyl-Trna Synthetase Is The Target Of Peptidenucleotide Antibiotic Microcin C, Anastasia Metlitskaya, Teymur Kazakov, Aigar Kommer, Olga Pavlova, Mette Praetorius-Ibba, Michael Ibba, Igor Krasheninnkov, Vyacheslav Kolb, Inessa Khmel, Konstantin Severinov

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Microcin C is a ribosome-synthesized heptapeptide that contains a modified adenosine monophosphate covalently attached to the C-terminal aspartate. Microcin C is a potent inhibitor of bacterial cell growth. Based on the in vivo kinetics of inhibition of macromolecular synthesis, Microcin C targets translation, through a mechanism that remained undefined. Here, we show that Microcin C is a subject of specific degradation inside the sensitive cell. The product of degradation, a modified aspartyl-adenylate containing an N-acylphosphoramidate linkage, strongly inhibits translation by blocking the function of aspartyl-tRNA synthetase.

C To U Editing Stimulates A To I Editing In The Anticodon Loop Of A Cytoplasmic Threonyl Trna In Trypanosoma Brucei, Mary Anne T. Rubio, Frank L. Ragone, Kirk W. Gaston, Michael Ibba, Juan D. Alfonzo

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Editing of tRNAs is widespread in nature and either changes the decoding properties or restores the folding of a tRNA. Unlike the phylogenetically disperse adenosine (A) to inosine (I) editing, cytosine (C) to uridine (U) editing has only been previously described in organellar tRNAs. We have shown that cytoplasmic tRNA^Thr(AGU) undergoes two distinct editing events in the anticodon loop: C to U and A to I. In vivo, every inosine-containing tRNA^Thr is also C to U edited at position 32. In vitro, C to U editing stimulates conversion of A to I at the wobble base. Although …

Linking Ligand-Induced Alterations In Androgen Receptor Structure To Differential Gene Expression: A First Step In The Rational Design Of Selective Androgen Receptor Modulators, Dmitri Kazmin, Tatiana Prytkova, C. Edgar Cook, Russell Wolfinger, Tzu-Ming Chu, David Beratan, J. D. Norris, Ching-Yi Chang, Donald P. Mcdonnell

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

We have previously identified a family of novel androgen receptor (AR) ligands that, upon binding, enable AR to adopt structures distinct from that observed in the presence of canonical agonists. In this report, we describe the use of these compounds to establish a relationship between AR structure and biological activity with a view to defining a rational approach with which to identify useful selective AR modulators. To this end, we used combinatorial peptide phage display coupled with molecular dynamic structure analysis to identify the surfaces on AR that are exposed specifically in the presence of selected AR ligands. Subsequently, we …

Methods For The Study Of Signaling Molecules In Membrane Lipid Rafts And Caveolae, Rennolds S. Ostrom, Paul A. Insel

Pharmacy Faculty Articles and Research

Lipid rafts and caveolae are cholesterol- and sphingolipid-rich microdomains of the plasma membrane that concentrate components of certain signal transduction pathways. Interest in and exploration of these microdomains has grown in recent years, especially after the discovery of the biochemical marker of caveolae, caveolin, and the recognition that caveolin interacts with many different signaling molecules via its scaffolding domain. There are three major types of caveolins (1, 2, and 3), with some selectivity in their expression in different tissues. Results assessing lipid raft/caveolae co-localization of molecules in signal transduction pathways have provided support for the idea that signaling components are …

Loss Of Editing Activity During The Evolution Of Mitochondrial Phenylalanyl-Trna Synthetase, Hervé Roy, Jiqiang Ling, Juan D. Alfonzo, Michael Ibba

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Accurate selection of amino acids is essential for faithful translation of the genetic code. Errors during amino acid selection are usually corrected by the editing activity of aminoacyl-tRNA synthetases such as phenylalanyl-tRNA synthetases (PheRS), which edit misactivated tyrosine. Comparison of cytosolic and mitochondrial PheRS from the yeast Saccharomyces cerevisiae suggested that the organellar protein might lack the editing activity. Yeast cytosolic PheRS was found to contain an editing site, which upon disruption abolished both cis and trans editing of Tyr-tRNA^Phe. Wild-type mitochondrial PheRS lacked cis and trans editing and could synthesize Tyr-tRNA^Phe, an activity enhanced in …

Specific Functions Of Synaptically Localized Potassium Channels In Synaptic Transmission At The Neocortical Gabaergic Fast-Spiking Cell Synapse, Ethan Goldberg, Shigeo Watanabe, Su Ying Chang, Rolf Joho, Z Josh Huang, Christopher S. Leonard, Bernardo Rudy

NYMC Faculty Publications

Potassium (K+) channel subunits of the Kv3 subfamily (Kv3.1-Kv3.4) display a positively shifted voltage dependence of activation and fast activation/deactivation kinetics when compared with other voltage-gated K+ channels, features that confer on Kv3 channels the ability to accelerate the repolarization of the action potential (AP) efficiently and specifically. In the cortex, the Kv3.1 and Kv3.2 proteins are expressed prominently in a subset of GABAergic interneurons known as fast-spiking (FS) cells and in fact are a significant determinant of the fast-spiking discharge pattern. However, in addition to expression at FS cell somata, Kv3.1 and Kv3.2 proteins also are expressed prominently at …

Association Between Archaeal Prolyl- And Leucyl-Trna Synthetases Enhances TrnaPro Aminoacylation, Mette Praetorius-Ibba, Theresa E. Rogers, Rachel Samson, Zvi Kelman, Michael Ibba

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Aminoacyl-tRNA synthetase-containing complexes have been identified in different eukaryotes, and their existence has also been suggested in some Archaea. To investigate interactions involving aminoacyl-tRNA synthetases in Archaea, we undertook a yeast two-hybrid screen for interactions between Methanothermobacter thermautotrophicus proteins using prolyl-tRNA synthetase (ProRS) as the bait. Interacting proteins identified included components of methanogenesis, protein-modifying factors, and leucyl-tRNA synthetase (LeuRS). The association of ProRS with LeuRS was confirmed in vitro by native gel electrophoresis and size exclusion chromatography. Determination of the steady-state kinetics of tRNA^Pro charging showed that the catalytic efficiency (k_cat/K_m) of ProRS increased 5-fold …

Defensin In The Ticks Dermacentor Variabilis And Ixodes Scapularis, Shane Michael Ceraul

Theses and Dissertations in Biomedical Sciences

This dissertation presents the identification, molecular structure and expression of defensin, an antimicrobial peptide, in the ticks, Dermacentor variabilis and Ixodes scapularis. A 624 bp cDNA molecule for defensin was cloned and sequenced from hemocytes, fat body and midgut of unstimulated D. variabilis ticks. Defensin peptide was detected only in the hemocyte lysates. These results suggest that the defensin from D. variabilis is synthesized and stored in the hemocytes, although the role of other tissues is not excluded.

The ability of the juvenile stage ticks to express the defensin gene was confirmed. Detection of the defensin transcript in all …

Quality Control During Aminoacyl-Trna Synthesis, M. Praetorius-Ibba, S. Ataide, C. Hausmann, J. Levengood, J. Ling, S. Wang, H. Roy, Michael Ibba

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

The fidelity of translation is determined at two major points: the accuracy of aminoacyl-tRNA selection by the ribosomes and synthesis of cognate amino acid/tRNA pairs by aminoacyl-tRNA synthetases (aaRSs) in the course of the aminoacylation reaction. The most important point in aminoacylation is the accurate recognition of cognate substrates coupled with discrimination of non-cognates. While this is generally accomplished by a single enzyme, we have recently found that discrimination against lysine analogues requires the existence of two unrelated lysyl-tRNA synthetases. For other amino acids, initial recognition is not sufficiently accurate with errors being corrected by an intrinsic editing activity. Recent …

Enterotoxin B Subunit Lectins As Adjuvants For Improvement Of Mucosal Vaccine, Nak-Won Choi

Loma Linda University Electronic Theses, Dissertations & Projects

In comparison with whole organism vaccines, subunit vaccines may be safer for immunization but may lack sufficient immunogenicity to provide complete immunity to the pathogen. To resolve this problem, bacterial and plant enterotoxin B subunit adjuvants containing a variety of receptor-binding properties were used to enhance the immunogenicity of rotavirus subunit vaccines. Enterotoxin B subunit adjuvants were employed to enhance protection against virus infection. Pentameric cholera toxin B subunit (CTB), shiga toxin-1 B subunit (STB) and monomeric ricin toxin B subunit (RTB) molecules were genetically linked to a 90 amino acid peptide from the simian rotavirus (SA11) nonstructural protein NSP4 …

The Potential Role Of Ledgf/P75 In Prostate Cancer, Tracy Ruth Daniels

Loma Linda University Electronic Theses, Dissertations & Projects

The serum autoantibody repertoire from cancer patients is currently being exploited for the identification of tumor associated antigens (TAA) and the design of TAA arrays. Such arrays would facilitate autoantibody profiling and potentially aid in the serological diagnosis and prognosis of tumors. The goal of this study was to identify and characterize prostate-specific TAA. We observed that while the general frequency and titers of autoantibodies in PCa patients were relatively similar to those in matched controls, significant differences could be detected between the two groups in the autoantibody response to the lens epithelial-derived growth factor p75 (LEDGF/p75). LEDGF/p75 is a …

Photoreactive Bicyclic Amino Acids As Substrates For Mutant Escherichia Coli Phenylalanyl-Trna Synthetases, Thomas Bentin, Ramin Hamzavi, Jahan Salomonsson, Hervé Roy, Michael Ibba, Peter E. Nielsen

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Unnatural amino acids carrying reactive groups that can be selectively activated under non-invasive biologically benign conditions are of interest in protein engineering as biological tools for the analysis of protein-protein and protein-nucleic acids interactions. The double ring system phenylalanine analogues benzofuranylalanine and benzotriazolylalanine were synthesized, and their photolability was tested by UV irradiation at 254, 320, and 365 nm. Although both showed photo reactivity, benzofuranylalanine appeared as the most promising compound because this amino acid was activated by UVA (long wavelength) irradiation. These amino acids were also tested for in vitro charging of tRNA^Phe and for protein mutagenesis via …

Divergence In Non-Cognate Amino Acid Recognition Between Class I And Class Ii Lysyl-Trna Synthetases, Jeffrey D. Levengood, Sandro F. Ataide, Hervé Roy, Michael Ibba

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Lysine insertion during coded protein synthesis requires lysyl-tRNA^Lys, which is synthesized by lysyl-tRNA synthetase (LysRS). Two unrelated forms of LysRS are known: LysRS2, which is found in eukaryotes, most bacteria, and a few archaea, and LysRS1, which is found in most archaea and a few bacteria. To compare amino acid recognition between the two forms of LysRS, the effects of l-lysine analogues on aminoacylation were investigated. Both enzymes showed stereospecificity toward the l-enantiomer of lysine and discriminated against noncognate amino acids with different R-groups (arginine, ornithine). Lysine analogues containing substitutions at other positions were generally most effective as …

The Evolving Role Of Lipid Rafts And Caveolae In G Protein-Coupled Receptor Signaling: Implications For Molecular Pharmacology, Rennolds S. Ostrom, Paul A. Insel

Pharmacy Faculty Articles and Research

The many components of G-protein-coupled receptor (GPCR) signal transduction provide cells with numerous combinations with which to customize their responses to hormones, neurotransmitters, and pharmacologic agonists. GPCRs function as guanine nucleotide exchange factors for heterotrimeric (α, β, γ) G proteins, thereby promoting exchange of GTP for GDP and, in turn, the activation of ‘downstream’ signaling components. Recent data indicate that individual cells express mRNA for perhaps over 100 different GPCRs (out of a total of nearly a thousand GPCR genes), several different combinations of G-protein subunits, multiple regulators of G-protein signaling proteins (which function as GTPase activating proteins), and various …

Nitric Oxide Inhibition Of Adenylyl Cyclase Type 6 Activity Is Dependent Upon Lipid Rafts And Caveolin Signaling Complexes, Rennolds S. Ostrom, Richard A. Bundey, Paul A. Insel

Pharmacy Faculty Articles and Research

Several cell types, including cardiac myocytes and vascular endothelial cells, produce nitric oxide (NO) via both constitutive and inducible isoforms of NO synthase. NO attenuates cardiac contractility and contributes to contractile dysfunction in heart failure, although the precise molecular mechanisms for these effects are poorly defined. Adenylyl cyclase (AC) isoforms type 5 and 6, which are preferentially expressed in cardiac myocytes, may be inhibited via a direct nitrosylation by NO. Because endothelial NO synthase (eNOS and NOS3), β-adrenergic ( AR) receptors, and AC6 all can localize in lipid raft/caveolin-rich microdomains, we sought to understand the role of lipid rafts in …

Aminoacyl-Trnas: Setting The Limits Of The Genetic Code, Michael Ibba, Dieter Söll

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Aminoacyl-tRNAs (aa-tRNAs) are simple molecules with a single purpose—to serve as substrates for translation. They consist of mature tRNAs to which an amino acid has been esterified at the 3′-end. The 20 different types of aa-tRNA are made by the 20 different aminoacyl-tRNA synthetases (aaRSs, of which there are two classes), one for each amino acid of the genetic code (Ibba and Söll 2000). This would be fine if it were not for the fact that such a straightforward textbook scenario is not true in a single known living organism. aa-tRNAs lie at the heart of gene expression; they interpret …

Phosphoproteomic Studies Of Smooth Muscle Contraction: Investigation Of Differential Phosphorylation In Relaxed/Contracted Rat Aortic Smooth Muscle Tissue Using Maldi-Tof Ms, Tonya M. Pekar

Theses, Dissertations and Capstones

Many human disorders are associated with the malfunction of smooth muscle tissue, or are related to the capabilities of its proper function—asthma, glaucoma, renal inefficiency, hypertension, and cardiovascular disease. Dysfunctional proteins are frequently implicated as the source of such disorders. As the second highest cause of death in the United States, the epidemic of cardiovascular disease makes the study of smooth muscle of utmost concern.

The capabilities of proteomics and mass spectrometry allow the entire proteome complement of a cell or tissue type to be analyzed at once. This investigation employs such techniques in an effort to better understand the …

Hypertonic Stress Co-Stimulates T Cell Il-2 Expression Through A Feedback Mechanism Involving Atp Release And P2 Receptor Activation Of P38 Map Kinase, William H. Loomis, Sachiko Namiki, Rennolds S. Ostrom, Paul A. Insel, Wolfgang G. Junger

Pharmacy Faculty Articles and Research

Hypertonic stress (HS) can alter the function of mammalian cells. We have reported that HS enhances differentiated responses of T cells by increasing their ability to produce interleukin (IL)-2, a finding of clinical interest because hypertonic infusions may modulate immune function in patients. HS shrinks cells and mechanically deforms membranes, which results in ATP release from many cell types. Here we investigate if ATP release is an underlying mechanism through which HS augments T cell function. We found that mechanical stress and HS induced rapid ATP release from Jurkat T cells. HS and exogenous ATP mobilized intracellular Ca2+, activated p38 …

Angiotensin Ii Enhances Adenylyl Cyclase Signaling Via Ca2+/Calmodulin. Gq-Gs Cross-Talk Regulates Collagen Production In Cardiac Fibroblasts, Rennolds S. Ostrom, Jennifer E. Naugle, Miki Hase, Caroline Gregorian, James S. Swaney, Paul A. Insel, Laurence L. Brunton, J. Gary Meszaros

Pharmacy Faculty Articles and Research

Cardiac fibroblasts regulate formation of extracellular matrix in the heart, playing key roles in cardiac remodeling and hypertrophy. In this study, we sought to characterize cross-talk between Gq and Gs signaling pathways and its impact on modulating collagen synthesis by cardiac fibroblasts. Angiotensin II (ANG II) activates cell proliferation and collagen synthesis but also potentiates cyclic AMP (cAMP) production stimulated by β-adrenergic receptors (β-AR). The potentiation of β-AR-stimulated cAMP production by ANG II is reduced by phospholipase C inhibition and enhanced by overexpression of Gq. Ionomycin and thapsigargin increased intracellular Ca2+ levels and potentiated isoproterenol- and forskolin-stimulated cAMP production, whereas …