Medical Sciences Commons^™

The Use Of Time-Resolved Fluorescence Imaging In The Study Of Protein Kinase C Localisation In Cells., Christopher D Stubbs, Stanley W Botchway, Simon J Slater, Anthony W Parker

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

BACKGROUND: Two-photon-excitation fluorescence lifetime imaging (2P-FLIM) was used to investigate the association of protein kinase C alpha (PKCalpha) with caveolin in CHO cells. PKCalpha is found widely in the cytoplasm and nucleus in most cells. Upon activation, as a result of increased intracellular Ca2+ and production of DAG, through G-protein coupled-phospholipase C signalling, PKC translocates to a variety of regions in the cell where it phosphorylates and interacts with many signalling pathways. Due to its wide distribution, discerning a particular interaction from others within the cell is extremely difficult. RESULTS: Fluorescence energy transfer (FRET), between GFP-PKCalpha and DsRed-caveolin, was used …

Hinderin, A Five-Domains Protein Including Coiled-Coil Motifs That Binds To Smc3., Chirag A Patel, Giancarlo Ghiselli

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

BACKGROUND: The structural maintenance of chromosome proteins SMC1 and SMC3 play an important role in the maintenance of chromosomal integrity by preventing the premature separation of the sister chromatids at the onset of anaphase. The two proteins are constitutive components of the multimeric complex cohesin and form dimers by interacting at their central globular regions. RESULTS: In order to identify proteins that by binding to SMC3 may interfere with the protein dimerization process, a human cDNA library was screened by the yeast two-hybrid system by using the hinge region of SMC3 as bait. This has lead to the identification of …

Characterization Of The Chicken Inward Rectifier K+ Channel Irk1/Kir2.1 Gene., Hideki Mutai, Lawrence C Kenyon, Emily Locke, Nami Kikuchi, John Carl Oberholtzer

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

BACKGROUND: Inward rectifier potassium channels (IRK) contribute to the normal function of skeletal and cardiac muscle cells. The chick inward rectifier K+ channel cIRK1/Kir2.1 is expressed in skeletal muscle, heart, brain, but not in liver; a distribution similar but not identical to that of mouse Kir2.1. We set out to explore regulatory domains of the cIRK1 promoter that enhance or inhibit expression of the gene in different cell types. RESULTS: We cloned and characterized the 5'-flanking region of cIRK1. cIRK1 contains two exons with splice sites in the 5'-untranslated region, a structure similar to mouse and human orthologs. cIRK1 has …

Control Of Mitochondrial Motility And Distribution By The Calcium Signal: A Homeostatic Circuit., Muqing Yi, David Weaver, György Hajnóczky

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

Mitochondria are dynamic organelles in cells. The control of mitochondrial motility by signaling mechanisms and the significance of rapid changes in motility remains elusive. In cardiac myoblasts, mitochondria were observed close to the microtubular array and displayed both short- and long-range movements along microtubules. By clamping cytoplasmic [Ca2+] ([Ca2+]c) at various levels, mitochondrial motility was found to be regulated by Ca2+ in the physiological range. Maximal movement was obtained at resting [Ca2+]c with complete arrest at 1-2 microM. Movement was fully recovered by returning to resting [Ca2+]c, and inhibition could be repeated with no apparent desensitization. The inositol 1,4,5-trisphosphate- or …

Inhibition Of Glucocorticoid-Induced Apoptosis By Targeting Splice Variants Of Bim Mrna With Small Interfering Rna And Short Hairpin Rna., Marc T. Abrams, Noreen M. Robertson, Kyonggeun Yoon, Eric Wickstrom

Department of Biochemistry and Molecular Biology Faculty Papers

Glucocorticoids (GCs) induce apoptosis in lymphocytes and are effective agents for the treatment of leukemia. The activated glucocorticoid receptor (GR) initiates a transcriptional program leading to caspase activation and cell death, but the critical signaling intermediates in GC-induced apoptosis remain largely undefined. We have observed that GC induction of the three major protein products of the Bcl-2 relative Bim (BimEL, BimS and BimL) correlates with GC sensitivity in a panel of human pre-B acute lymphoblastic leukemia (ALL) cell lines. To test the hypothesis that Bim facilitates GC-induced apoptosis, we reduced BIM mRNA levels and Bim protein levels by RNA interference …

Heme Oxygenase-2 Gene Deletion Attenuates Oxidative Stress In Neurons Exposed To Extracellular Hemin., Raymond F Regan, Jing Chen, Luna Benvenisti-Zarom

Department of Emergency Medicine Faculty Papers

BACKGROUND: Hemin, the oxidized form of heme, accumulates in intracranial hematomas and is a potent oxidant. Growing evidence suggests that it contributes to delayed injury to surrounding tissue, and that this process is affected by the heme oxygenase enzymes. In a prior study, heme oxygenase-2 gene deletion increased the vulnerability of cultured cortical astrocytes to hemin. The present study tested the effect of HO-2 gene deletion on protein oxidation, reactive oxygen species formation, and cell viability after mixed cortical neuron/astrocyte cultures were incubated with neurotoxic concentrations of hemin. RESULTS: Continuous exposure of wild-type cultures to 1-10 microM hemin for 14 …

Durable Cytotoxic Immune Responses Against Gp120 Elicited By Recombinant Sv40 Vectors Encoding Hiv-1 Gp120 +/- Il-15., Hayley J Mckee, Patricia Y T'Sao, Maria Vera, Puri Fortes, David S Strayer

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

BACKGROUND: A vaccine that elicits durable, powerful anti-HIV immunity remains an elusive goal. In these studies we tested whether multiple treatments with viral vector-delivered HIV envelope antigen (gp120), with and without IL-15, could help to approach that goal. For this purpose, we used recombinant Tag-deleted SV40-derived vectors (rSV40s), since they do not elicit neutralizing antibody responses, and so can be given multiply without loss of transduction efficiency. METHODS: SV(gp120) carried the coding sequences for HIV-1NL4-3 Env, and SV(mIL-15) carried the cDNA for mouse IL-15. Singly, and in combination, these two vectors were given monthly to BALB/cJ mice. Cytotoxic immunity and …

Trichloroethylene And Cardiac Malformations, Robert L. Brent

The Selected Works of Robert Brent

No abstract.

Hsp27 Anti-Sense Oligonucleotides Sensitize The Microtubular Cytoskeleton Of Chinese Hamster Ovary Cells Grown At Low Ph To 42 Degrees C-Induced Reorganization, Michael T. Hargis, C. W. Storck, Eric Wickstrom, Leonid A. Yakubov, Dennis B. Leeper, Ronald A. Coss

Department of Biochemistry and Molecular Biology Faculty Papers

Chinese hamster ovary (CHO) cells maintained in vitro at pH 6.7 were used to model cells in the acidic environment of tumours. CHO cells grown at pH 6.7 develop thermotolerance during 42 degrees C heating at pH 6.7 and their cytoskeletal systems are resistant to 42 degrees C-induced perinuclear collapse. Hsp27 levels are elevated in cells grown at pH 6.7 and are further induced during 42 degrees C heating, while Hsp70 levels remain low or undetectable, suggesting that Hsp27 is responsible for some of the novel characteristics of these cells. An anti-sense oligonucleotide strategy was used to test the importance …

Biochemical Enrichment And Biophysical Characterization Of A Taste Receptor For L-Arginine From The Catfish, Ictalurus Puntatus., William Grosvenor, Yuri Kaulin, Andrew I Spielman, Douglas L Bayley, D Lynn Kalinoski, John H Teeter, Joseph G Brand

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

BACKGROUND: The channel catfish, Ictalurus punctatus, is invested with a high density of cutaneous taste receptors, particularly on the barbel appendages. Many of these receptors are sensitive to selected amino acids, one of these being a receptor for L-arginine (L-Arg). Previous neurophysiological and biophysical studies suggested that this taste receptor is coupled directly to a cation channel and behaves as a ligand-gated ion channel receptor (LGICR). Earlier studies demonstrated that two lectins, Ricinus communis agglutinin I (RCA-I) and Phaseolus vulgaris Erythroagglutinin (PHA-E), inhibited the binding of L-Arg to its presumed receptor sites, and that PHA-E inhibited the L-Arg-stimulated ion conductance …

Gitr Activation Induces An Opposite Effect On Alloreactive Cd4(+) And Cd8(+) T Cells In Graft-Versus-Host Disease., Stephanie J Muriglan, Teresa Ramirez-Montagut, Onder Alpdogan, Thomas W Van Huystee, Jeffrey M Eng, Vanessa M Hubbard, Adam A Kochman, Kartono H Tjoe, Carlo Riccardi, Pier Paolo Pandolfi, Shimon Sakaguchi, Alan N Houghton, Marcel R M Van Den Brink

Department of Medical Oncology Faculty Papers

Glucocorticoid-induced tumor necrosis factor receptor family-related gene (GITR) is a member of the tumor necrosis factor receptor (TNFR) family that is expressed at low levels on unstimulated T cells, B cells, and macrophages. Upon activation, CD4(+) and CD8(+) T cells up-regulate GITR expression, whereas immunoregulatory T cells constitutively express high levels of GITR. Here, we show that GITR may regulate alloreactive responses during graft-versus-host disease (GVHD) after allogeneic bone marrow transplantation (BMT). Using a BMT model with major histocompatibility complex class I and class II disparity, we demonstrate that GITR stimulation in vitro and in vivo enhances alloreactive CD8(+)CD25(-) T …

The Nad(P)H Oxidase Homolog Nox4 Modulates Insulin-Stimulated Generation Of H202 And Plays An Integral Role In Insulin Signal Transduction, Kalyankar Mahadev, Hiroyuki Motoshima, Xiangdong Wu, Jean Marie Ruddy, Rebecca S. Arnold, Guangjie Cheng, J. David Lambeth, Barry J. Goldstein

Department of Medicine Faculty Papers

Insulin stimulation of target cells elicits a burst of H₂O₂ that enhances tyrosine phosphorylation of the insulin receptor and its cellular substrate proteins as well as distal signaling events in the insulin action cascade. The molecular mechanism coupling the insulin receptor with the cellular oxidant-generating apparatus has not been elucidated. Using reverse transcription-PCR and Northern blot analyses, we found that Nox4, a homolog of gp91phox, the phagocytic NAD(P)H oxidase catalytic subunit, is prominently expressed in insulin-sensitive adipose cells. Adenovirus-mediated expression of Nox4 deletion constructs lacking NAD(P)H or FAD/NAD(P)H cofactor binding domains acted in a dominant-negative …

Indinavir And Rifabutin Drug Interactions In Healthy Volunteers., Walter K. Kraft, Jacqueline B. Mccrea, Gregory A. Winchell, Alexandra Carides, Richard C. Lowry, Eric J. Woolf, Sandra E. Kusma, Paul J. Deutsch, Howard E Greenberg, Scott A. Waldman

Department of Medicine Faculty Papers

Two studies examined the pharmacokinetics of indinavir and rifabutin when coadministered in healthy subjects. Rifabutin, which induces the expression of cytochrome P450 (CYP) 3A, and indinavir, which inhibits that enzyme system, are frequently coadministered in patients infected with HIV. The second study was undertaken to determine if altering the dose of rifabutin coadministered with indinavir would minimize the drug interaction observed in the first study. Two studies, each with a three-period crossover design, were performed. In study 1, standard doses of rifabutin and indinavir (300 mg of rifabutin qd and 800 mg indinavir q8h) were administered as monotherapy (with placebo …

Signaling Switches And Bistability Arising From Multisite Phosphorylation In Protein Kinase Cascades., Nick I Markevich, Jan B. Hoek, Boris N. Kholodenko

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

Mitogen-activated protein kinase (MAPK) cascades can operate as bistable switches residing in either of two different stable states. MAPK cascades are often embedded in positive feedback loops, which are considered to be a prerequisite for bistable behavior. Here we demonstrate that in the absence of any imposed feedback regulation, bistability and hysteresis can arise solely from a distributive kinetic mechanism of the two-site MAPK phosphorylation and dephosphorylation. Importantly, the reported kinetic properties of the kinase (MEK) and phosphatase (MKP3) of extracellular signal-regulated kinase (ERK) fulfill the essential requirements for generating a bistable switch at a single MAPK cascade level. Likewise, …

Commentary: Teratology In The 20th Century Environmental Causes Of Congenital Malformations In Humans And How They Were Established By Harold Kalter, Robert L. Brent

The Selected Works of Robert Brent

No abstract

Utilization Of Juvenile Animals Studies To Determine The Human Effects And Risks Of Environmental Toxicants During Postnatal Developmental Stages, Robert L. Brent

The Selected Works of Robert Brent

Toxicology studies utilizing animals and in-vitro cellular or tissue preparations have been used to study the toxic effects and mechanism of action of drugs and chemicals and to determine the effective and safe dose of drugs in humans and the risk of toxicity from chemical exposures. Testing in animals could be improved if animal dosing using the mg/kg basis was abandoned and drugs and chemicals were administered to compare the effects of pharmacokinetically and toxicokinetically equivalent serum levels in the animal model and human. Since alert physicians or epidemiology studies, not animal studies have discovered most human teratogens and toxicities …

Nuovi Approcci Terapeutici Contro Il Cancro Del Colon, Giovanni Mario Pitari

Department of Pharmacology and Experimental Therapeutics Faculty Papers

This presentation was given in Augusta (Siracusa, Italy) for the 2004 Paul Harris Fellow Award, Rotary Foundation of Rotary International. The lecture discusses the clinical significance of the GC-C pathway and its potential as a therapeutic target for colon cancer and metastatic tumors. It underscores the importance of the dysregulation of the GC-C pathway in promoting colorectal tumorigenesis and of dietary calcium in the GC-C-mediated chemoprevention.

Questa e’ la presentazione per il Premio 2004 Paul Harris Fellow del Rotary International (Augusta, Siracusa, Italia). La dissertazione illustra l’importante significato clinico della via moleculare regulata da GC-C e dai suoi ligandi (guanilina, …

The Pharmacokinetics Of Nebulized Nanocrystal Budesonide Suspension In Healthy Volunteers., Walter Kraft, Barry Steiger, Don Beussink, John N. Quiring, Nancy Fitzgerald, Howard E. Greenberg, Scott A. Waldman

Department of Medicine Faculty Papers

Nanocrystal budesonide (nanobudesonide) is a suspension for nebulization in patients with steroid-responsive pulmonary diseases such as asthma. The pharmacokinetics and safety of the product were compared to those of Pulmicort Respules. Sixteen healthy volunteers were administered nanobudesonide 0.5 and 1.0 mg, Pulmicort Respules 0.5 mg, and placebo in a four-way, randomized crossover design. All nebulized formulations were well tolerated, with no evidence of bronchospasm. Nebulization times were significantly shorter for nanobudesonide compared to Pulmicort Respules. Because of a low oral bioavailability, plasma concentration of budesonide is a good marker of lung-delivered dose. The pharmacokinetics of nanobudesonide 0.5 and 1.0 mg …

Embryonic Origins Of A Motor System: Motor Dendrites Form A Myotopic Map In Drosophila, Matthias Landgraf, Victoria Jeffrey, Miki Fujioka, James B. Jaynes, Michael Bate

Department of Biochemistry and Molecular Biology Faculty Papers

The organisational principles of locomotor networks are less well understood than those of many sensory systems, where in-growing axon terminals form a central map of peripheral characteristics. Using the neuromuscular system of the Drosophila embryo as a model and retrograde tracing and genetic methods, we have uncovered principles underlying the organisation of the motor system. We find that dendritic arbors of motor neurons, rather than their cell bodies, are partitioned into domains to form a myotopic map, which represents centrally the distribution of body wall muscles peripherally. While muscles are segmental, the myotopic map is parasegmental in organisation. It forms …

Il-7 Enhances Peripheral T Cell Reconstitution After Allogeneic Hematopoietic Stem Cell Transplantation., Onder Alpdogan, Stephanie J Muriglan, Jeffrey M Eng, Lucy M Willis, Andrew S Greenberg, Barry J Kappel, Marcel R M Van Den Brink

Department of Medical Oncology Faculty Papers

We used clinically relevant murine allogeneic bone marrow transplantation (BMT) models to study the mechanisms by which IL-7 administration can improve posttransplant peripheral T cell reconstitution. After transplant we could distinguish two populations of mature donor T cells: (a) alloreactive T cells with decreased expression of CD127 (IL-7 receptor alpha chain) and (b) nonalloreactive T cells, which express CD127 and undergo homeostatic proliferation. IL-7 administration increased the homeostatic proliferation of nonalloreactive T cells, but had no effect on alloreactive T cells and the development of graft-versus-host disease. Allogeneic transplant of purified hematopoietic stem cells and adoptive transfer of thymocytes into …

Characterization Of Mutations And Loss Of Heterozygosity Of P53 And K-Ras2 In Pancreatic Cancer Cell Lines By Immobilized Polymerase Chain Reaction, James Butz, Eric Wickstrom, Jeremy Edwards

Department of Biochemistry and Molecular Biology Faculty Papers

Background

The identification of known mutations in a cell population is important for clinical applications and basic cancer research. In this work an immobilized form of the polymerase chain reaction, referred to as polony technology, was used to detect mutations as well as gene deletions, resulting in loss of heterozygosity (LOH), in cancer cell lines. Specifically, the mutational hotspots in p53, namely codons 175, 245, 248, 249, 273, and 282, and K-ras2, codons 12, 13 and 61, were genotyped in the pancreatic cell line, Panc-1. In addition LOH analysis was also performed for these same two genes in Panc-1 by …

Transfection Of Il-10 Expression Vectors Into Endothelial Cultures Attenuates Alpha4beta7-Dependent Lymphocyte Adhesion Mediated By Madcam-1., Makoto Sasaki, Paul Jordan, Jeff Houghton, Xianmin Meng, Makoto Itoh, Takashi Joh, J Steven Alexander

Department of Dermatology and Cutaneous Biology Faculty Papers

BACKGROUND: Enhanced expression of MAdCAM-1 (mucosal addressin cell adhesion molecule-1) is associated with the onset and progression of inflammatory bowel disease. The clinical significance of elevated MAdCAM-1 expression is supported by studies showing that immunoneutralization of MAdCAM-1, or its ligands reduce inflammation and mucosal damage in models of colitis. Interleukin-10 (IL-10) is an endogenous anti-inflammatory and immunomodulatory cytokine that has been shown to prevent inflammation and injury in several animal studies, however clinical IL-10 treatment remains insufficient because of difficulties in the route of IL-10 administration and its biological half-life. Here, we examined the ability of introducing an IL-10 expression …

Myosin Heavy Chain And Physiological Adaptation Of The Rat Diaphragm In Elastase-Induced Emphysema., Dong Kwan Kim, Jianliang Zhu, Benjamin W Kozyak, James M Burkman, Neal A Rubinstein, Edward B Lankford, Hansell H Stedman, Taitan Nguyen, Sanford Levine, Joseph B Shrager

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

BACKGROUND: Several physiological adaptations occur in the respiratory muscles in rodent models of elastase-induced emphysema. Although the contractile properties of the diaphragm are altered in a way that suggests expression of slower isoforms of myosin heavy chain (MHC), it has been difficult to demonstrate a shift in MHCs in an animal model that corresponds to the shift toward slower MHCs seen in human emphysema. METHODS: We sought to identify MHC and corresponding physiological changes in the diaphragms of rats with elastase-induced emphysema. Nine rats with emphysema and 11 control rats were studied 10 months after instillation with elastase. MHC isoform …

Signaling And Regulation Of G Protein-Coupled Receptors In Airway Smooth Muscle., Charlotte K Billington, Raymond B Penn

Department of Medicine Faculty Papers

Signaling through G protein-coupled receptors (GPCRs) mediates numerous airway smooth muscle (ASM) functions including contraction, growth, and "synthetic" functions that orchestrate airway inflammation and promote remodeling of airway architecture. In this review we provide a comprehensive overview of the GPCRs that have been identified in ASM cells, and discuss the extent to which signaling via these GPCRs has been characterized and linked to distinct ASM functions. In addition, we examine the role of GPCR signaling and its regulation in asthma and asthma treatment, and suggest an integrative model whereby an imbalance of GPCR-derived signals in ASM cells contributes to the …

High-Resolution Physical Map For Chromosome 16q12.1-Q13, The Blau Syndrome Locus., Xiaoju Wang, Helena Kuivaniemi, Gina Bonavita, Charlene J Williams, Gerard Tromp

Department of Medicine Faculty Papers

BACKGROUND: The Blau syndrome (MIM 186580), an autosomal dominant granulomatous disease, was previously mapped to chromosome 16p12-q21. However, inconsistent physical maps of the region and consequently an unknown order of microsatellite markers, hampered us from further refining the genetic locus for the Blau syndrome. To address this problem, we constructed our own high-resolution physical map for the Blau susceptibility region. RESULTS: We generated a high-resolution physical map that provides more than 90% coverage of a refined Blau susceptibility region. The map consists of four contigs of sequence tagged site-based bacterial artificial chromosomes with a total of 124 bacterial artificial chromosomes, …

Stretch-Induced Calcium Release In Smooth Muscle., Guangju Ji, Robert J Barsotti, Morris E Feldman, Michael I Kotlikoff

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

Smooth muscle cells undergo substantial increases in length, passively stretching during increases in intraluminal pressure in vessels and hollow organs. Active contractile responses to counteract increased transmural pressure were first described almost a century ago (Bayliss, 1902) and several mechanisms have been advanced to explain this phenomenon. We report here that elongation of smooth muscle cells results in ryanodine receptor-mediated Ca(2+) release in individual myocytes. Mechanical elongation of isolated, single urinary bladder myocytes to approximately 120% of slack length (DeltaL = 20) evoked Ca(2+) release from intracellular stores in the form of single Ca(2+) sparks and propagated Ca(2+) waves. Ca(2+) …

Characterization Of Subcellular Localization And Stability Of A Splice Variant Of G Alpha I2., Philip B Wedegaertner

Department of Microbiology and Immunology Faculty Papers

BACKGROUND: Alternative mRNA splicing of alpha(i2), a heterotrimeric G protein alpha subunit, has been shown to produce an additional protein, termed salpha(i2). In the salpha(i2) splice variant, 35 novel amino acids replace the normal C-terminal 24 amino acids of alpha(i2). Whereas alpha(i2) is found predominantly at cellular plasma membranes, salpha(i2) has been localized to intracellular Golgi membranes, and the unique 35 amino acids of salpha(i2) have been suggested to constitute a specific targeting signal. RESULTS: This paper proposes and examines an alternative hypothesis: disruption of the normal C-terminus of alpha(i2) produces an unstable protein that fails to localize to plasma …

Medical, Social And Legal Implications Of Treating Nausea And Vomiting Of Pregnancy, Robert L. Brent

The Selected Works of Robert Brent

This article will deal with medical, social, and legal implications of treating nausea and vomiting of pregnancy (NVP). Clinical problems occur when the symptoms become exaggerated and result in debilitation, dehydration, and hospitalization. The treatment of NVP in its early stages has the implication that it will prevent the more serious complications, including hospitalization. Therapeutic modalities discussed in this conference that have been used or are being tested are primarily symptomatic treatments (antihistamines, Bendectin (Merrell Dow; Cincinatti, Ohio), phenothiazines, hyponosis, accupressure, relaxation behavioral modification, audiogenic feedback training, newer medications, diet, and nutritional support). Bendectin is probably the most studied medication …

Vdac-Dependent Permeabilization Of The Outer Mitochondrial Membrane By Superoxide Induces Rapid And Massive Cytochrome C Release., M Madesh, György Hajnóczky

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

Enhanced formation of reactive oxygen species (ROS), superoxide (O2*-), and hydrogen peroxide (H2O2) may result in either apoptosis or other forms of cell death. Here, we studied the mechanisms underlying activation of the apoptotic machinery by ROS. Exposure of permeabilized HepG2 cells to O2*- elicited rapid and massive cytochrome c release (CCR), whereas H2O2 failed to induce any release. Both O2*- and H2O2 promoted activation of the mitochondrial permeability transition pore by Ca2+, but Ca2+-dependent pore opening was not required for O2*--induced CCR. Furthermore, O2*- alone evoked CCR without damage of the inner mitochondrial membrane barrier, as mitochondrial membrane potential …

Proteolytic Release Of Cd44 Intracellular Domain And Its Role In The Cd44 Signaling Pathway., I Okamoto, Y Kawano, D Murakami, T Sasayama, N Araki, T Miki, A J Wong, H Saya

Department of Microbiology and Immunology Faculty Papers

CD44 is a widely distributed cell surface adhesion molecule and is implicated in diverse biological processes. However, the nature of intracellular signaling triggered by CD44 remains to be elucidated. Here, we show that CD44 undergoes sequential proteolytic cleavage in the ectodomain and intracellular domain, resulting in the release of a CD44 intracellular domain (ICD) fragment. Consequently, CD44ICD acts as a signal transduction molecule, where it translocates to the nucleus and activates transcription mediated through the 12-O-tetradecanoylphorbol 13-acetate-responsive element, which is found in numerous genes involved in diverse cellular processes. Expression of an uncleavable CD44 mutant as well as metalloprotease inhibitor …