Dicty News Electronic Edition Volume 23, number 5 August 6, 2004 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 Dicty-News, the Dicty Reference database and other useful information is available at dictyBase - http://dictybase.org. ============= Abstracts ============= Evolutionarily conserved modules in actin nucleation: lessons from Dictyostelium and plants F. Cvrkov (1), F. Rivero (2) and B. Bavlnka (3) (1) Department of Plant Physiology, Faculty of Sciences, Charles University, Prague, Czechia (2) Center for Biochemistry, Medical Faculty, University of Cologne, Cologne, Germany (3) Laboratory of Cell Biology, Institute of Experimental Botany, Academy of Sciences of the Czech Republic, Prague, Czechia Protoplasma, in press Summary. The actin cytoskeleton plays a central part in the dynamic organization of eukaryotic cell structure. Nucleation of actin filaments is a crucial step in the establishment of new cytoskeletal structures or modification of existing ones, providing abundant targets for regulatory processes. A substantial part of our understanding of actin nucleation derives from studies on yeast and metazoan cells. However, recent advances in structural and functional genome analysis in less traditional models, such as plants or Dictyostelium, provide an emerging picture of an evolutionarily conserved core of at least two actin nucleation mechanisms, one mediated by the Arp2/3 complex and the other one by the formin-based module. A considerable degree of conservation is found also in the systems controlling the F-actin/G-actin balance (profilin, ADF/cofilin) and even in certain regulatory aspects, such as the involvement of Rho-related small GTPases. Identification of such conserved elements provides a prerequisite for the characterization of evolutionarily variable aspects of actin regulation, which may be responsible for the rich morphological diversity of eukaryotic cells. Note: it took so long for Protoplasma to have the manuscript published that today, with the Dicty genome finished, an update of some details would be needed. However the main ideas are still valid and therefore the review should be useful to those interested. Submitted by: Francisco Rivero [francisco.rivero@uni-koeln.de] ============================================================================== [End Dicty News, volume 23, number 5]