dictyNews Electronic Edition Volume 33, number 3 July 24, 2009 Please submit abstracts of your papers as soon as they have been accepted for publication by sending them to dicty@northwestern.edu or by using the form at http://dictybase.org/db/cgi-bin/dictyBase/abstract_submit. Back issues of dictyNews, the Dicty Reference database and other useful information is available at dictyBase - http://dictybase.org. ========= Abstracts ========= How a Cell Crawls and the Role of Cortical Myosin II David R. Soll, Deborah Wessels, Spencer Kuhl, and Daniel F. Lusche Eukaryotic Cell, in press Employing 3D-DIAS software, Dictyostelium discoideum amoebae translocating  on a glass surface in the absence of chemoattractant have been reconstructed  at five second intervals and motion-analyzed. A morphometric analysis of  pseudopods, the main cell body and the uropod provides a comprehensive  description of the basic motile behavior of a cell in 4D, resulting in a list  of 18 characteristics. A similar analysis of the myosin II phosphorylation  mutant 3XASP reveals a role for the cortical localization of myosin II in the  suppression of lateral pseudopods, the formation of the uropod, cytoplasmic  distribution of cytoplasm in the main cell body and efficient motility. The  analysis suggests that pseudopods, the main cell body, and the uropod  represent three motility compartments that must be coordinated for  efficient translocation.  It provides a contextual framework for interpreting  the effects of mutations, inhibitors and chemoattractants on the basic  motile behavior of D. discoideum. The generality of the characteristics  of the basic motile behavior of D. discoideum must now be tested by  similar 4D analyses of the motility of higher eukaryotic cells, in particular  human polymorphonuclear leukocytes.  Submitted by Deb Wessels [deborah-wessels@uiowa.edu] -------------------------------------------------------------------------------- Development of Dictyostelium discoideum is associated with alteration of  fucosylated N-glycan structures Birgit Schiller, Alba Hykollari, Josef Voglmeir, Gerald Pöltl, Karin Hummel,  Ebrahim Razzazi-Fazeli, Rudolf Geyer and Iain B. H. Wilson Department für Chemie, Universität für Bodenkultur, Vienna A-1190, Austria Biochem. J., in press (doi:10.1042/BJ20090786) The social amoeba Dictyostelium discoideum has become established  as a simple model for the examination of cell-cell interactions and early  studies suggested that shifts in glycosylation profiles take place during  its life cycle. In the present study, we have applied HPLC and mass  spectrometric methods to show that the major N-glycans in axenic cultures  of the AX3 strain are oligomannosidic forms, most of which carry core fucose  and/or intersecting and bisecting N-acetylglucosamine residues, including  the major structure with the composition Man8GlcNAc4Fuc1. The postulated  alpha1,3-linkage of the core fucose which correlates with the cross-reactivity  of Dictyostelium glycoproteins with an anti-horseradish peroxidase antiserum;  a corresponding core alpha1,3-fucosyltransferase activity capable of modifying  oligomannosidic N-glycans was detected in axenic Dictyostelium extracts.  The presence of fucose on the N-glycans and the reactivity to the antiserum, but not the fucosyltransferase activity, are abolished in the fucose-deficient  HL250 strain. In later stages of development, N-glycans at the mound and  culmination stages show a reduction in both the size and the degree of  modification by intersecting/bisecting residues as compared to mid-log  phase cultures, consistent with the hypothesis that glycosidase and  glycosyltransferase expression levels are altered during the slime mould  life cycle. Submitted by Iain Wilson [iain.wilson@boku.ac.at] -------------------------------------------------------------------------------- Differentiation-Inducing Factor-1 and -2 Function Also as Modulators for  Dictyostelium Chemotaxis Hidekazu Kuwayama 1 and Yuzuru Kubohara 2,* 1 Graduate School of Life and Environmental Sciences, University of Tsukuba,  Tsukuba 305-8572, Japan 2 Department of Molecular and Cellular Biology, Institute for Molecular and  Cellular Regulation (IMCR), Gunma University, Maebashi 371-8512, Japan PLoS ONE, in press Background: In the early stages of development of the cellular slime mold  Dictyostelium discoideum, chemotaxis toward cAMP plays a pivotal role in  organizing discrete cells into a multicellular structure. In this process,  a series of signaling molecules, such as G-protein-coupled cell surface  receptors for cAMP, phosphatidylinositol metabolites, and cyclic nucleotides,  function as the signal transducers for controlling dynamics of cytoskeleton.  Differentiation-inducing factor-1 and -2 (DIF-1 and DIF-2) were originally  identified as the factors (chlorinated alkylphenones) that induce  Dictyostelium stalk cell differentiation, but it remained unknown whether  the DIFs had any other physiologic functions. Methodology/Principal Findings: To further elucidate the functions of DIFs,  in the present study we investigated their effects on chemotaxis under various  conditions. Quite interestingly, in shallow cAMP gradients, DIF-1 suppressed  chemotaxis whereas DIF-2 promoted it greatly. Analyses with various mutants  revealed that DIF-1 may inhibit chemotaxis, at least in part, via GbpB  (a phosphodiesterase) and a decrease in the intracellular cGMP concentration  ([cGMP]i). DIF-2, by contrast, may enhance chemotaxis, at least in part,  via RegA (another phosphodiesterase) and an increase in [cGMP]i. Using null  mutants for DimA and DimB, the transcription factors that are required for  DIF-dependent prestalk differentiation, we also showed that the mechanisms  for the modulation of chemotaxis by DIFs differ from those for the induction  of cell differentiation by DIFs, at least in part. Conclusions/Significance: Our findings indicate that DIF-1 and DIF-2  function as negative and positive modulators for Dictyostelium chemotaxis,  respectively. To our knowledge, this is the first report in any organism of  physiologic modulators (small molecules) for chemotaxis having  differentiation-inducing activity. Yuzuru Kubohara [kubohara@showa.gunma-u.ac.jp] -------------------------------------------------------------------------------- Regulation of IL-2 production in Jurkat cells by Dictyostelium-derived factors Katsunori Takahashi, Masami Murakami, Kohei Hosaka, Haruhisa Kikuchi,  Yoshiteru Oshima, Yuzuru Kubohara* *Department of Molecular and Cellular Biology, Institute for Molecular and  Cellular Regulation, Gunma University, Maebashi 371-8512, Japan Life Sciences , in press Aims: Differentiation-inducing factors (DIFs) are chlorinated alkylphenones  found in the cellular slime mold Dictyostelium discoideum. DIF derivatives  exhibit antiproliferative activities and promote glucose consumption in  mammalian cells in vitro. In this study, we assessed the ability of DIFs to  regulate the immune system and investigated their mechanisms of action. Main methods: We examined the effects of 30 DIF derivatives on concanavalin  A–induced IL-2 production (CIIP) in Jurkat T-cells. We also examined the  effects of some DIF derivatives on the activity of AP-1 (activator protein-1),  NFAT (nuclear factor of activated T-cells), and NFkB (nuclear factor kappa B),  which are transcription factors required for CIIP.  Key findings: Of the derivatives tested, some compounds suppressed CIIP as  well as the known immunosuppressants cyclosporine A and FK506. A reporter  gene assay revealed that 4 DIF derivatives tested suppressed CIIP, at least  in part, by inhibiting the activity of AP-1, NFAT, and/or NFkB. Unlike  cyclosporine A and FK506, the DIF derivatives had little effect on  concanavalin A–induced interferon-gamma production in Jurkat cells. Significance: The present results suggest that DIF derivatives could be  developed as novel immunosuppressive drugs. Submitted by: Yuzuru Kubohara [kubohara@showa.gunma-u.ac.jp] ============================================================== [End dictyNews, volume 33, number 3]