A Rho GDP-dissociation inhibitor is involved in cytokinesis of Dictyostelium.
Homology searches toward the EST databases of Dictyostelium discoideum identified two putative Rho GDP-dissociation inhibitors (RhoGDIs), RhoGDI1 and RhoGDI2. In this study, the roles of RhoGDI1 in cytokinesis were examined. The RhoGDI1-null Dictyostelium strains produced by homologous recombination were viable but generated multinucleate giant cells in suspension culture, suggesting that RhoGDI1 is involved in cytokinesis. The expression of green fluorescent protein (GFP)-tagged RhoGDI1 complemented the defects of the RhoGDI1-null cells, and the GFP-RhoGDI1 is predominantly present in cytoplasm of the cell-like yeast RhoGDI. Of 15 Rho family GTPases in Dictyostelium currently known, Dictyostelium versions of Rac1 proteins (Rac1A, Rac1B, and Rac1C) and RacE that are reportedly involved in Dictyostelium cytokinesis, showed two-hybrid interactions with RhoGDI1 as well as human and yeast Cdc42. These results suggest that RhoGDI1 is involved in cytokinesis of Dicytostelium through the regulation of Rho family GTPases Rac1s and/or RacE.
Imai
Keita
K
Department of Biotechnology, Graduate School of Agricultural and Life Sciences, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, Japan.
Kijima
Toshirou
T
Noda
Yoichi
Y
Sutoh
Kazuo
K
Yoda
Koji
K
Adachi
Hiroyuki
H
D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D002455:Cell Division / Q000502:physiology*; D004023:Dictyostelium / Q000166:cytology / Q000235:genetics / Q000502:physiology*; D020224:Expressed Sequence Tags; D017930:Genes, Reporter; D005816:Genetic Complementation Test; D020730:Guanine Nucleotide Dissociation Inhibitors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008969:Molecular Sequence Data; D015800:Protozoan Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D016415:Sequence Alignment; D020798:Two-Hybrid System Techniques; D020744:rac GTP-Binding Proteins / Q000378:metabolism; D020741:rho GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*
D020730:Guanine Nucleotide Dissociation Inhibitors; D015800:Protozoan Proteins; D011993:Recombinant Fusion Proteins; D020744:rac GTP-Binding Proteins; D020741:rho GTP-Binding Proteins