title: Rho GTPase signaling in Dictyostelium discoideum: insights from the genome.
abstract: Rho GTPases are ubiquitously expressed across the eukaryotes where they act as molecular switches participating in the regulation of many cellular processes. We present an inventory of proteins involved in Rho-regulated signaling pathways in Dictyostelium discoideum that have been identified in the completed genome sequence. In Dictyostelium the Rho family is encoded by 18 genes and one pseudogene. Some of the Rho GTPases (Rac1a/b/c, RacF1/F2 and RacB) are members of the Rac subfamily, and one, RacA, belongs to the RhoBTB subfamily. The Cdc42 and Rho subfamilies, characteristic of metazoa and fungi, are absent. The activities of these GTPases are regulated by two members of the RhoGDI family, by eight members of the Dock180/zizimin family and by a surprisingly large number of proteins carrying RhoGEF (42 genes) or RhoGAP (43 genes) domains or both (three genes). Most of these show domain compositions not found in other organisms, although some have clear homologs in metazoa and/or fungi. Among the (in many cases putative) effectors found in Dictyostelium are the CRIB domain proteins (WASP and two related proteins, eight PAK kinases and a novel gelsolin-related protein), components of the Scar/WAVE complex, 10 formins, four IQGAPs, two members of the PCH family, numerous lipid kinases and phospholipases, and components of the NADPH oxidase and the exocyst complexes. In general, the repertoire of Rho signaling components of Dictyostelium is similar to that of metazoa and fungi.
authors.affiliation: Center for Biochemistry of the Medical Faculty and Center for Molecular Medicine Cologne, University of Cologne, Joseph-Stelzmann-Str. 52, D-50931 Cologne, Germany.
authors.forename: Georgia
authors.initials: G
authors.lastname: Vlahou
authors.forename: Francisco
authors.initials: F
authors.lastname: Rivero
mesh_terms: D043203:1-Alkyl-2-acetylglycerophosphocholine Esterase / Q000235:genetics / Q000378:metabolism; D000818:Animals; D016213:Cyclins / Q000235:genetics / Q000378:metabolism; D004023:Dictyostelium / Q000235:genetics / Q000502:physiology; D005326:Fetal Proteins / Q000235:genetics / Q000378:metabolism; D000080865:Formins; D020690:GTPase-Activating Proteins / Q000235:genetics / Q000378:metabolism; D018503:Genome, Protozoan; D020730:Guanine Nucleotide Dissociation Inhibitors / Q000235:genetics / Q000378:metabolism; D020662:Guanine Nucleotide Exchange Factors / Q000235:genetics / Q000378:metabolism; D008840:Microfilament Proteins / Q000235:genetics / Q000378:metabolism; D008869:Microtubule-Associated Proteins / Q000235:genetics / Q000378:metabolism; D005810:Multigene Family; D019255:NADPH Oxidases / Q000235:genetics / Q000378:metabolism; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D010740:Phospholipases / Q000235:genetics / Q000378:metabolism; D010802:Phylogeny; D017434:Protein Structure, Tertiary; D064067:Rho Guanine Nucleotide Exchange Factors; D015398:Signal Transduction / Q000502:physiology*; D020703:ras GTPase-Activating Proteins / Q000235:genetics / Q000378:metabolism; D020741:rho GTP-Binding Proteins / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D062947:rho-Specific Guanine Nucleotide Dissociation Inhibitors
chemical_list: D016213:Cyclins; D005326:Fetal Proteins; D000080865:Formins; D020690:GTPase-Activating Proteins; D020730:Guanine Nucleotide Dissociation Inhibitors; D020662:Guanine Nucleotide Exchange Factors; C101203:IQ motif containing GTPase activating protein 1; D008840:Microfilament Proteins; D008869:Microtubule-Associated Proteins; D009687:Nuclear Proteins; D064067:Rho Guanine Nucleotide Exchange Factors; D020703:ras GTPase-Activating Proteins; C085379:rho GTPase-activating protein; D062947:rho-Specific Guanine Nucleotide Dissociation Inhibitors; D019255:NADPH Oxidases; D010740:Phospholipases; D043203:1-Alkyl-2-acetylglycerophosphocholine Esterase; C513190:Pafah1b1 protein, mouse; D020741:rho GTP-Binding Proteins