title: A Ras subfamily GTPase shows cell cycle-dependent nuclear localization.
abstract: Previously characterized Ras subfamily proteins have been found to be predominantly associated with the plasma membrane where they function in signal transduction pathways to convey extracellular signals to intracellular targets. Here, we provide evidence that the Dictyostelium Ras subfamily protein RasB has a novel subcellular localization and function. The protein is predominantly localized in the nucleus during most of the cell cycle. Furthermore, during mitosis and cytokinesis RasB assumes a diffuse cellular localization despite the fact that the nuclear membrane stays intact. The linkage between the position of RasB in the cell and division suggests that it may have a role in nuclear division. Consistent with this idea, rasB- cells exhibit severe growth defects and cells overexpressing an activated version of RasB are multinucleate.
authors.affiliation: Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada.
authors.forename: B W
authors.initials: BW
authors.lastname: Sutherland
authors.forename: G B
authors.initials: GB
authors.lastname: Spiegelman
authors.forename: G
authors.initials: G
authors.lastname: Weeks
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002453:Cell Cycle; D002455:Cell Division; D002467:Cell Nucleus / Q000378:metabolism; D004023:Dictyostelium; D019084:Fluorescent Antibody Technique, Indirect; D007425:Intracellular Membranes / Q000378:metabolism; D008938:Mitosis; D013347:Subcellular Fractions / Q000378:metabolism; D013997:Time Factors; D018631:ras Proteins / Q000096:biosynthesis* / Q000737:chemistry*
chemical_list: D018631:ras Proteins