a cytohesin homolog in dictyostelium amoebae盘基网柄菌变形虫cytohesin同系物.pdfVIP

A Cytohesin Homolog in Dictyostelium Amoebae 1 ¨ 1 1 ¨ 1,2 3 Maria Christina Shina , Rolf Muller , Rosemarie Blau-Wasser , Gernot Glockner , Michael Schleicher , 1 1 4 Ludwig Eichinger , Angelika A. Noegel *, Waldemar Kolanus * 1 Center for Biochemistry, Medical Faculty, Center for Molecular Medicine Cologne (CMMC) and Cologne Excellence Cluster on Cellular Stress Responses in Aging- ¨ Associated Diseases (CECAD), University of Cologne, Koln, Germany, 2 Leibniz Institute for Age Research - Fritz-Lipmann-Institute e.V., Jena, Germany, 3 Institute of Anatomy and Cell Biology and Center for Integrated Protein Science (CIPSM), Ludwig-Maximilians-University, Muenchen, Germany, 4 Laboratory of Molecular Immunology, LIMES Institute of the University of Bonn, Bonn, Germany Abstract Background: Dictyostelium, an amoeboid motile cell, harbors several paralogous Sec7 genes that encode members of three distinct subfamilies of the Sec7 superfamily of Guanine nucleotide exchange factors. Among them are proteins of the GBF/ BIG family present in all eukaryotes. The third subfamily represented with three members in D. discoideum is the cytohesin family that has been thought to be metazoan specific. Cytohesins are characterized by a Sec7 PH tandem domain and have roles in cell adhesion and migration. Principal Findings: Dictyostelium SecG exhibits highest homologies to the cytohesins. It harbors at its amino terminus several ankyrin repeats that are followed by the Sec7 PH tande