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Selective pharmacological inhibition of phosphoinositide 3-kinase p110delta opposes the progression of autoimmune diabetes in non-obese diabetic (NOD) mice Caylib A. Durand, Martin J. Richer, Kathrin Brenker, Marcia Graves, Iryna Shanina, Kate Choi, Marc S. Horwitz, Kamal D. Puri, and Michael R. Gold
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Gene clusters found in bacterial species classified as Streptomyces encode the majority of known antibiotics as well as many pharmaceutically active compounds. A site-specific recombination system similar to those that mediate plasmid conjugation was engineered to catalyze tandem amplification of one of these gene clusters in a heterologous Streptomyces species. Three genetic elements were known to be required for DNA amplification in S. kanamyceticus: the oriT-like recombination sites RsA and RsB, and ZouA, a site-specific relaxase similar to TraA proteins that catalyze plasmid transfer. We inserted RsA and RsB sequences into the S. coelicolor genome flanking a cluster of 22 genes (act) responsible for biosynthesis of the polyketide antibiotic actinorhodin. |
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Cofilin-Mediated F-Actin Severing Is Regulated by the Rap GTPase and Controls the Cytoskeletal Dynamics That Drive Lymphocyte Spreading and BCR Microcluster Formation Spencer A. Freeman, Victor Lei, May Dang-Lawson, Kensaku Mizuno, Calvin D. Roskelley, and Michael R. Gold
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Preventing the activation or cycling of the Rap1 GTPase alters adhesion and cytoskeletal dynamics and blocks metastatic melanoma cell extravasation into the lungs. The Rap1 GTPase is a master regulator of cell adhesion, polarity, and migration. We show that both blocking Rap1 activation and expressing a constitutively active form of Rap1 reduced the ability of B16F1 melanoma cells to extravasate from the microvasculature and form metastatic lesions in the lungs. This correlated with a decreased ability of the tumor cells to undergo transendothelial migration (TEM) in vitro and form dynamic, F-actin-rich pseudopodia that penetrate capillary endothelial walls in vivo. Using multiple tumor cell lines, we show that the inability to form these membrane protrusions, which likely promote TEM and extravasation, can be explained by altered adhesion dynamics and impaired cell polarization that result when Rap1 activation or cycling is perturbed. Thus, targeting Rap1 could be a useful approach for reducing the metastatic dissemination of tumor cells that undergo active TEM. Copyright 2010 AACR. |
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Martin Hartmann,Charles G Howes, David VanInsberghe, Hang Yu, Dipankar Bachar, Richard Christen, Rolf Henrik Nilsson, Steven J Hallam, and William W Mohn.
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The Department of Microbiology & Immunology
The University of British Columbia
2350 Health Sciences Mall Vancouver, BC Canada V6T 1Z3
