Scientific Report 2003-2004 - Cleveland Clinic Lerner Research ...

MOLECULAR BIOLOGY — PAGE 101Confocal micrograph of mouse colon tissue from an animal treated with dextran sulfate to induce experimentalcolitis. Sections were fluorescently labeled for hyaluronan (green), inter-alpha inhibitor (red) and nuclei (blue).Image produced in the laboratory of Ganesh Sen, Ph.D. From Kessler, S., de la Motte, C., Drazba, J., Sen,G., and S. Strong.MOLECULAR CARDIOLOGY — PAGE 118Top image: Molecular surface of PINCH LIM domain involved in mediating cell adhesion. The regions coloredin blue are involved in protein-protein recognition in focal adhesion assembly. From the laboratory of Jun Qin,Ph.D.Middle image on right: Agonist binding pocket of the α1-Adrenergic Receptor. A molecular model of theα1A-AR as shown from the extracellular surface. Alpha-carbon coordinates were taken from the bacteriorhodopsinmodel and adjusted based upon the results of several mutagenesis studies from the laboratory of DiannePerez, Ph.D. Residues that been identified to be involved in agonist binding are shown in space-filled representationand are listed under its respective transmembrane domain (TM) in order from the extracellular surface.Amino acid residues are numbered according to the rat α1A-AR sequence.Lower image: Vitamin K-dependent (VKD) proteins are modified by the VKD- or gamma-carboxylase, an integralmembrane enzyme that resides in the endoplasmic reticulum. Carboxylation occurs during the secretion ofVKD proteins in a process that is poorly understood. The VKD proteins have a sequence (the pink rectangle)that the carboxylase binds with high affinity, which selectively targets VKD proteins for carboxylation. Thecarboxylase uses the oxygenation of vitamin K hydroquinone (KH 2, illustrated by the orange napthoquinone) tovitamin K epoxide (KO) to convert glutamic acid residues in VKD proteins to carboxylated glutamic acids (indicatedby white Y’s). Clusters of glutamic acids are modified (3 in this example) to render the VKD proteinsactive in functions that include hemostasis, growth control, bone metabolism and signal transduction. Normally,fully carboxylated VKD proteins are generated; however, conditions that limit the supply of KH 2block carboxylationand result in the secretion of uncarboxylated- and partially-carboxylated forms of inactive VKD proteins.Warfarin limits KH 2by inhibiting the reductase that regenerates KH 2from KO and is a commonly-used anticoagulant.From the laboratory of Kathy Berkner, Ph.D.NEUROSCIENCES — PAGE 133Lower left and right, uppermost central panel: Cultured hippocampal neurons immunofluorescently stainedfor syntaxin (red) and neurofilament (green). Images by Xiaoquin Liu, from the laboratory of Mark Perin, Ph.D.Central middle and lower panel: In situ hybridization for ephrin mRNAs and ligands in embryonic chick cerebellum,detected using alkaline phosphatase substrate. Reproduced from Nishida et al., 2002, Development129:5647-58 with permission.Background and remaining panels: Oligodendrocytes and oligodendrocyte progenitors expressing enhancedgreen fluorescent protein and immunolabeled for NG2 proteoglycan (red). Reproduced from Mallon et al., 2002,Journal of Neuroscience 22: 876-85 with permission.Page design by Graham Kidd, Ph.D., Department of Neuroscience.CENTERS OF RESEARCH — PAGE 153Top image: Molecular surface of PINCH LIM domain involved in mediating cell adhesion. The regions coloredin blue are involved in protein-protein recognition in focal adhesion assembly. From the laboratory of Jun Qin,Ph.D.Middle image: Three dimensional backbone trace of PINCH LIM domain involved in mediating cell adhesion.Regions involved in protein recognition are highlighted by amino side chains (blue). From the laboratory of JunQin, Ph.D.Lower image: A biological “Trojan Horse” utilizing receptor-mediated Cbl uptake as a means of targeting NO-Cbl to neoplasms. Nitrosylcobalamin (NO-Cbl) is delivered to cells bound to plasma transcobalamin II (TC II).TC II, a non-glycosylated plasma protein (43-kD), binds to specific cell surface receptors (TC II-R) that recognizethe TC II-Cbl complex (holo-TC II) preferentially to apoTC II (TC II alone). The TC II-R:TC II:NO-Cbl complexis internalized via endocytosis and TC II-NO-Cbl is delivered to lysosomes where NO is released fromCbl, and TC II is subsequently degraded. The chemotherapeutic effectiveness of NO-Cbl is based on the cytotoxicproperties of nitric oxide (NO). NO is oxidized from NO-Cbl in lysosomes at acidic pH. The NO free radicalinduces cytotoxicity through increased oxidative stress, inhibition of cellular metabolism, and direct DNAdamage, leading to apoptosis and/or necrosis. By Joseph Bauer, Ph.D., in the laboratory of Dan Lindner,M.D., Ph.D.Continued on Page 200199