Universität zu Köln

The Dictyostelium discoideum RACK1 orthologue has roles in growth and development

Omosigho, Napoleon Nosa (2014) The Dictyostelium discoideum RACK1 orthologue has roles in growth and development. PhD thesis, Universität zu Köln.

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    Abstract

    The receptor for activated C-kinase 1 (RACK1) is a conserved protein belonging to the WD40 repeat family of proteins. It folds into a beta propeller with seven blades which allow interactions with many proteins. Thus it can serve as a scaffolding protein and have roles in several cellular processes. We identified the product of the Dictyostelium discoideum gpbB gene as the Dictyostelium RACK1 homolog. The protein is mainly cytosolic but can also associate with cellular membranes. DdRACK1 binds to phosphoinositides (PIPs) in protein-lipid overlay and liposomes-binding assays. The basis of this activity resides in a basic region located in the extended loop between blades 6 and 7 as revealed by mutational analysis. Similar to RACK1 proteins from other organisms DdRACK1 interacts with G protein subunits alpha, beta and gamma as shown by yeast two-hybrid, pulldown, and immunoprecipitation assays. Unlike the Saccharomyces cerevisiae and Cryptococcus neoformans RACK1 proteins it does not appear to take over Gβ function in D. discoideum as developmental and other defects were not rescued in Gβ null mutants overexpressing GFP-DdRACK1. Overexpression of GFP-tagged DdRACK1 and a mutant version (DdRACK1mut) which carried a charge-reversal mutation in the basic region in wild type cells led to changes during growth and development. DdRACK1 interacts with heterotrimeric G proteins and can through these interactions impact on processes specifically regulated by these proteins.

    Item Type: Thesis (PhD thesis)
    Creators:
    CreatorsEmail
    Omosigho, Napoleon Nosanapnices@yahoo.com
    URN: urn:nbn:de:hbz:38-56341
    Subjects: Natural sciences and mathematics
    Life sciences
    Uncontrolled Keywords:
    KeywordsLanguage
    Dictyostelium discoideumUNSPECIFIED
    RACK1UNSPECIFIED
    WD-repeat proteinsUNSPECIFIED
    Faculty: Mathematisch-Naturwissenschaftliche Fakultät
    Divisions: Mathematisch-Naturwissenschaftliche Fakultät > Biochemie I
    Language: English
    Date: 06 May 2014
    Date Type: Publication
    Date of oral exam: 24 June 2014
    Full Text Status: Public
    Date Deposited: 01 Jul 2014 15:35:16
    Referee
    NameAcademic Title
    Noegel, AngelikaProf. Dr.
    Hülskamp, MartinProf. Dr.
    Arndt, HartmutProf. Dr.
    URI: http://kups.ub.uni-koeln.de/id/eprint/5634

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