1887

Abstract

RasG-regulated signal transduction has been linked to a variety of growth-specific processes and appears to also play a role in the early development of . In an attempt to uncover some of the molecular components involved in Ras-mediated signalling, several proteins have been described previously, including the cell adhesion molecule DdCAD-1, whose phosphorylation state was affected by the expression of the constitutively activated RasG, RasG(G12T). Here it has been shown that a null strain lacks the phosphoproteins that were tentatively identified as DdCAD-1, confirming its previous designation. Further investigation revealed that cells expressing RasG(G12T) exhibited increased cell–cell cohesion, concomitant with reduced levels of DdCAD-1 phosphorylation. This increased cohesion was DdCAD-1-dependent and was correlated with increased localization of DdCAD-1 at the cell surface. DdCAD-1 phosphorylation was also found to decrease during aggregation. These results revealed a possible role for protein phosphorylation in regulating DdCAD-1-mediated cell adhesion during early development. In addition, the levels of DdCAD-1 protein were substantially reduced in a null cell line. These results indicate that RasG affects both the expression and dephosphorylation of DdCAD-1 during early development.

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2006-05-01
2019-10-19
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References

  1. Beug, H., Katz, F. E., Stein, A. & Gerisch, G. ( 1973; ). Quantitation of membrane sites in aggregating Dictyostelium cells by use of tritiated univalent antibody. Proc Natl Acad Sci U S A 70, 3150–3154.[CrossRef]
    [Google Scholar]
  2. Brar, S. K. & Siu, C. H. ( 1993; ). Characterization of the cell adhesion molecule gp24 in Dictyostelium discoideum. Mediation of cell–cell adhesion via a Ca2+-dependent mechanism. J Biol Chem 268, 24902–24909.
    [Google Scholar]
  3. Choi, A. H. & Siu, C. H. ( 1987; ). Filopodia are enriched in a cell cohesion molecule of Mr 80,000 and participate in cell–cell contact formation in Dictyostelium discoideum. J Cell Biol 104, 1375–1387.[CrossRef]
    [Google Scholar]
  4. Coates, J. C. & Harwood, A. J. ( 2001; ). Cell–cell adhesion and signal transduction during Dictyostelium development. J Cell Sci 114, 4349–4358.
    [Google Scholar]
  5. Faix, J., Gerisch, G. & Noegel, A. A. ( 1992; ). Overexpression of the csA cell adhesion molecule under its own cAMP-regulated promoter impairs morphogenesis in Dictyostelium. J Cell Sci 102, 203–214.
    [Google Scholar]
  6. Fukui, Y., Yumura, S. & Yumura-Kitanishi, T. ( 1987; ). Agar-overlay immuno-fluorescence: high resolution studies of cytoskeletal components and their changes during chemotaxis. Methods Cell Biol 28, 347–356.
    [Google Scholar]
  7. Gerisch, G. ( 1968; ). Cell aggregation and differentiation in Dictyostelium. Curr Top Dev Biol 3, 157–197.
    [Google Scholar]
  8. Jamora, C. & Fuchs, E. ( 2002; ). Intercellular adhesion, signalling and the cytoskeleton. Nat Cell Biol 4, E101–E108.[CrossRef]
    [Google Scholar]
  9. Juliano, R. L. ( 2002; ). Signal transduction by cell adhesion receptors and the cytoskeleton: functions of integrins, cadherins, selectins, and immunoglobulin-superfamily members. Annu Rev Pharmacol Toxicol 42, 283–323.[CrossRef]
    [Google Scholar]
  10. Kae, H., Lim, C. J., Spiegelman, G. B. & Weeks, G. ( 2004; ). Chemoattractant-induced Ras activation during Dictyostelium aggregation. EMBO Rep 5, 602–606.[CrossRef]
    [Google Scholar]
  11. Kessin, R. H. ( 2001; ). Dictyostelium – Evolution, Cell Biology, and the Development of Multicellularity. Cambridge: Cambridge University Press.
  12. Khosla, M., Spiegelman, G. B., Weeks, G., Sands, T. W., Virdy, K. J. & Cotter, D. A. ( 1994; ). RasG protein accumulation occurs just prior to amoebae emergence during spore germination in Dictyostelium discoideum. FEMS Microbiol Lett 117, 293–298.[CrossRef]
    [Google Scholar]
  13. Khosla, M., Spiegelman, G. B. & Weeks, G. ( 1996; ). Overexpression of an activated rasG gene during growth blocks the initiation of Dictyostelium development. Mol Cell Biol 16, 4156–4162.
    [Google Scholar]
  14. Knecht, D. A., Fuller, D. L. & Loomis, W. F. ( 1987; ). Surface glycoprotein, gp24, involved in early adhesion of Dictyostelium discoideum. Dev Biol 121, 277–283.[CrossRef]
    [Google Scholar]
  15. Lam, T. Y., Pickering, G., Geltosky, J. & Siu, C. H. ( 1981; ). Differential cell cohesiveness expressed by prespore and prestalk cells of Dictyostelium discoideum. Differentiation 20, 22–28.[CrossRef]
    [Google Scholar]
  16. Lickert, H., Bauer, A., Kemler, R. & Stappert, J. ( 2000; ). Casein kinase II phosphorylation of E-cadherin increases E-cadherin/β-catenin interaction and strengthens cell–cell adhesion. J Biol Chem 275, 5090–5095.[CrossRef]
    [Google Scholar]
  17. Lilien, J., Balsamo, J., Arregui, C. & Xu, G. ( 2002; ). Turn-off, drop-out: functional state switching of cadherins. Dev Dyn 224, 18–29.[CrossRef]
    [Google Scholar]
  18. Lim, C. J., Spiegelman, G. B. & Weeks, G. ( 2001; ). RasC is required for optimal activation of adenylyl cyclase and Akt/PKB during aggregation. EMBO J 20, 4490–4499.[CrossRef]
    [Google Scholar]
  19. Muller, K. & Gerisch, G. ( 1978; ). A specific glycoprotein as the target site of adhesion blocking Fab in aggregating Dictyostelium cells. Nature 274, 445–449.[CrossRef]
    [Google Scholar]
  20. Nelson, W. J. & Nusse, R. ( 2004; ). Convergence of Wnt, beta-catenin, and cadherin pathways. Science 303, 1483–1487.[CrossRef]
    [Google Scholar]
  21. Primpke, G., Iassonidou, V., Nellen, W. & Wetterauer, B. ( 2000; ). Role of cAMP-dependent protein kinase during growth and early development of Dictyostelium discoideum. Dev Biol 221, 101–111.[CrossRef]
    [Google Scholar]
  22. Secko, D. M., Khosla, M., Gaudet, P., Tsang, A., Spiegelman, G. B. & Weeks, G. ( 2001; ). RasG regulates discoidin gene expression during Dictyostelium growth. Exp Cell Res 266, 135–141.[CrossRef]
    [Google Scholar]
  23. Secko, D. M., Insall, R. H., Spiegelman, G. B. & Weeks, G. ( 2004; ). The identification of Dictyostelium phosphoproteins altered in response to the activation of RasG. Proteomics 4, 2629–2639.[CrossRef]
    [Google Scholar]
  24. Sesaki, H. & Siu, C. H. ( 1996; ). Novel redistribution of the Ca2+-dependent cell adhesion molecule DdCAD-1 during development of Dictyostelium discoideum. Dev Biol 177, 504–516.[CrossRef]
    [Google Scholar]
  25. Sesaki, H., Wong, E. F. & Siu, C. H. ( 1997; ). The cell adhesion molecule DdCAD-1 in Dictyostelium is targeted to the cell surface by a nonclassical transport pathway involving contractile vacuoles. J Cell Biol 138, 939–951.[CrossRef]
    [Google Scholar]
  26. Tuxworth, R. I., Cheetham, J. L., Machesky, L. M., Spiegelmann, G. B., Weeks, G. & Insall, R. H. ( 1997; ). Dictyostelium RasG is required for normal motility and cytokinesis, but not growth. J Cell Biol 138, 605–614.[CrossRef]
    [Google Scholar]
  27. Watts, D. & Ashworth, J. ( 1970; ). Growth of myxamoebae of the cellular slime mould Dictyostelium discoideum in axenic culture. Biochem J 119, 171–174.
    [Google Scholar]
  28. Weeks, G. & Spiegelman, G. B. ( 2003; ). Roles played by Ras subfamily proteins in the cell and developmental biology of microorganisms. Cell Signal 15, 901–909.[CrossRef]
    [Google Scholar]
  29. Wong, E. F., Brar, S. K., Sesaki, H., Yang, C. & Siu, C. H. ( 1996; ). Molecular cloning and characterization of DdCAD-1, a Ca2+-dependent cell–cell adhesion molecule, in Dictyostelium discoideum. J Biol Chem 271, 16399–16408.[CrossRef]
    [Google Scholar]
  30. Wong, E., Yang, C., Wang, J., Fuller, D., Loomis, W. F. & Siu, C. H. ( 2002; ). Disruption of the gene encoding the cell adhesion molecule DdCAD-1 leads to aberrant cell sorting and cell-type proportioning during Dictyostelium development. Development 129, 3839–3850.
    [Google Scholar]
  31. Yang, C., Brar, S. K., Desbarats, L. & Siu, C. H. ( 1997; ). Synthesis of the Ca2+-dependent cell adhesion molecule DdCAD-1 is regulated by multiple factors during Dictyostelium development. Differentiation 61, 275–284.[CrossRef]
    [Google Scholar]
  32. Zeng, C., Anjard, C., Riemann, K., Konzok, A. & Nellen, W. ( 2000; ). gdt1, a new signal transduction component for negative regulation of the growth-differentiation transition in Dictyostelium discoideum. Mol Biol Cell 11, 1631–1643.[CrossRef]
    [Google Scholar]
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